The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
N. Leclerc Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ I. Lecoeur-Taibi
Gaia Data Release 3: The extragalactic content††thanks: Table 8 is only
available in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ S. Liao Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
E.L. Licata Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ H.E.P. Lindstrøm
Gaia Data Release 3: The extragalactic content††thanks: Table 8 is only
available in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ T.A. Lister Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
E. Livanou Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Lobel Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Lorca Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
C. Loup Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ P. Madrero Pardo
Gaia Data Release 3: The extragalactic content††thanks: Table 8 is only
available in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Magdaleno Romeo Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ S. Managau Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
R.G. Mann Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ M. Manteiga Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ J.M. Marchant Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
M. Marconi Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ J. Marcos Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ M.M.S. Marcos Santos Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ D. Marín Pina Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
S. Marinoni Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
F. Marocco Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ D.J. Marshall Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ L. Martin Polo Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ J.M. Martín-Fleitas Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ G. Marton Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
N. Mary Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Masip Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ D. Massari Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
A. Mastrobuono-Battisti Gaia Data Release 3: The extragalactic
content††thanks: Table 8 is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ T. Mazeh Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ P.J. McMillan Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
S. Messina Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ D. Michalik Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ N.R. Millar Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
A. Mints Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ D. Molina Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ R. Molinaro Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
L. Molnár Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ G. Monari Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ M. Monguió Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
P. Montegriffo Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Montero Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ R. Mor Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Mora Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ R. Morbidelli Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
T. Morel Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ D. Morris Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ T. Muraveva Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
C.P. Murphy Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ I. Musella Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ Z. Nagy Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
L. Noval Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ F. Ocaña Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Ogden
Gaia Data Release 3: The extragalactic content††thanks: Table 8 is only
available in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ C. Ordenovic Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
J.O. Osinde Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ C. Pagani Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ I. Pagano Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
L. Palaversa Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
P.A. Palicio Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ L. Pallas-Quintela
Gaia Data Release 3: The extragalactic content††thanks: Table 8 is only
available in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Panahi Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
S. Payne-Wardenaar Gaia Data Release 3: The extragalactic content††thanks:
Table 8 is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ X. Peñalosa Esteller
Gaia Data Release 3: The extragalactic content††thanks: Table 8 is only
available in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Penttil ̈a Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
B. Pichon Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A.M. Piersimoni Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ F.-X. Pineau Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
E. Plachy Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ G. Plum Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ E. Poggio Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Prša Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ L. Pulone Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
E. Racero Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
S. Ragaini Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ M. Rainer Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ P. Ramos
Gaia Data Release 3: The extragalactic content††thanks: Table 8 is only
available in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ M. Ramos-
Lerate Gaia Data Release 3: The extragalactic content††thanks: Table 8 is only
available in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ P. Re Fiorentin Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ S. Regibo Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
P.J. Richards Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ C. Rios Diaz Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ V. Ripepi Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
A. Riva Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ H.-W. Rix Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ G. Rixon Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
N. Robichon Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A.C. Robin Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ C. Robin Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
M. Roelens Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ H.R.O. Rogues Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ L. Rohrbasser Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
M. Romero-Gómez Gaia Data Release 3: The extragalactic content††thanks: Table
8 is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ N. Rowell Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ F. Royer Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
D. Ruz Mieres Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ K.A. Rybicki Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ G. Sadowski Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
A. Sáez Núñez Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Sagristà Sellés
Gaia Data Release 3: The extragalactic content††thanks: Table 8 is only
available in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ J. Sahlmann Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
E. Salguero Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ N. Samaras Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ V. Sanchez
Gimenez Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ N. Sanna Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ R. Santoveña Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
M. Sarasso Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ M. Schultheis Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ E. Sciacca Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
M. Segol Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ J.C. Segovia Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ D. Ségransan Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
D. Semeux Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ S. Shahaf Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ H.I. Siddiqui Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
A. Siebert Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
L. Siltala Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Silvelo Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ E. Slezak Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
I. Slezak Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ R.L. Smart Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ O.N. Snaith Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
E. Solano Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ F. Solitro Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ D. Souami Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ J. Souchay Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Spagna Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
L. Spina Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ F. Spoto Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ I.A. Steele Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
H. Steidelm ̈uller Gaia Data Release 3: The extragalactic content††thanks:
Table 8 is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ C.A. Stephenson Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ M. S ̈uveges
Gaia Data Release 3: The extragalactic content††thanks: Table 8 is only
available in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ J. Surdej Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ L. Szabados Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ E. Szegedi-Elek Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ F. Taris Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
M.B. Taylor Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ L. Tolomei Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ N. Tonello Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
F. Torra Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ J. Torra† Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ G. Torralba Elipe Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ M. Trabucchi Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A.T. Tsounis Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ C. Turon Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
A. Ulla Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ N. Unger Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ M.V. Vaillant Gaia Data Release
3: The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
E. van Dillen Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ W. van Reeven Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ O. Vanel Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
A. Vecchiato Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ Y. Viala Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ D. Vicente Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
S. Voutsinas Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ M. Weiler Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ T. Wevers Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ Ł. Wyrzykowski Gaia
Data Release 3: The extragalactic content††thanks: Table 8 is only available
in electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ A. Yoldas Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
P. Yvard Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ H. Zhao Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ J. Zorec Gaia Data Release 3:
The extragalactic content††thanks: Table 8 is only available in electronic
form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/
S. Zucker Gaia Data Release 3: The extragalactic content††thanks: Table 8 is
only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/Gaia Data Release 3: The
extragalactic content††thanks: Table 8 is only available in electronic form at
the CDS at http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ T. Zwitter Gaia Data
Release 3: The extragalactic content††thanks: Table 8 is only available in
electronic form at the CDS at http://cdsweb.u-strasbg.fr/cgi-
bin/qcat?J/A+A/Gaia Data Release 3: The extragalactic content††thanks: Table 8
is only available in electronic form at the CDS at
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/

(First submitted 31 January 2022. Resubmitted 27 April 2022\. Accepted 27
April 2022)

The Gaia Galactic survey mission is designed and optimized to obtain
astrometry, photometry, and spectroscopy of nearly two billion stars in our
Galaxy. Yet as an all-sky multi-epoch survey, Gaia also observes several
million extragalactic objects down to a magnitude of $G\sim 21$ mag. Due to
the nature of the Gaia onboard-selection algorithms, these are mostly point-
source-like objects. Using data provided by the satellite, we have identified
quasar and galaxy candidates via supervised machine learning methods, and
estimate their redshifts using the low resolution BP/RP spectra. We further
characterise the surface brightness profiles of host galaxies of quasars and
of galaxies from pre-defined input lists. Here we give an overview of the
processing of extragalactic objects, describe the data products in Gaia DR3,
and analyse their properties. Two integrated tables contain the main results
for a high completeness, but low purity (50–70%), set of 6.6 million candidate
quasars and 4.8 million candidate galaxies. We provide queries that select
purer sub-samples of these containing 1.9 million probable quasars and 2.9
million probable galaxies (both $\sim$95% purity). We also use high quality
BP/RP spectra of 43 thousand high probability quasars over the redshift range
0.05–4.36 to construct a composite quasar spectrum spanning restframe
wavelengths from 72–1000 nm.

##  1 Introduction

The primary objective of the Gaia mission is to study the structure and origin
of our Galaxy by measuring the distribution, kinematics, and physical
properties of its constituent stars (Gaia Collaboration et al., 2016). The
satellite and its observing strategy were therefore designed to optimize the
measurement of astrometry, photometry, and spectroscopy of point sources.
Nonetheless, by observing the entire sky multiple times down to a limiting
magnitude of $G\simeq 21$ mag, Gaia has observed millions of extragalactic
objects since it started observing in mid 2014. Various data on many of these
objects are provided as part of the third Gaia data release (DR3), covering
both previously-identified objects and new candidate objects identified using
the Gaia data. The purpose of this paper is to summarize how extragalactic
objects were identified, what their properties are, and what data on them are
provided in Gaia DR3.

Extragalactic objects are classified or analysed by several modules in the
Gaia data processing system. These modules were provided by different
coordination units (CUs) within the Data Processing and Analysis Consortium
(DPAC) and operate largely independently. They are as follows: CU3 Astrometry,
which assembled a list of extragalactic point sources from external catalogues
to use in defining the astrometric reference frame (Gaia Collaboration &
Klioner et al., 2022); CU4 Extended Objects (EO), which analyses the surface
brightness profiles of an input list of objects to look for physical
extension; CU7 Variability, which uses photometric light curves to
characterise variability; CU8 Astrophysical Parameters, which uses astrometry,
photometry, and the BP/RP spectra to classify objects and to estimate
redshifts. Whereas the modules from CU3 and CU4 work on a predefined lists of
extragalactic objects identified in other surveys, the Vari module in CU7 and
the Discrete Source Classifier (DSC) module in CU8 use supervised machine
learning to discover new objects. These classifiers use only Gaia data. The
inclusion of additional data, such as infrared photometry, should improve the
classification performance (sample completeness and purity). However, a key
principle of the DPAC is to provide homogeneous classifications based only on
the Gaia data, unaffected by issues with other catalogues, such as
incompleteness.

It is important to realise that there is no common definition of quasar or
galaxy across the various Gaia modules. A common definition is also not
possible, because each module uses different data to classify or select
objects, including different training sets. But broadly speaking, the term
’extragalactic’ in the context of this paper refers to unresolved or barely
resolved individual objects more than 50 Mpc from the Sun.

If Gaia were to obtain noise-free, unbiased parallaxes, then identifying
extragalactic objects would be simple: They would be all the objects with
parallaxes below some threshold. Yet we do not have this luxury: Despite the
high precision of Gaia DR3 parallaxes – around 0.5 mas at $G=20$ mag and 0.25
mas at $G=19$ mag (Lindegren et al., 2021b) – this is not nearly enough to
reliably identify extragalactic objects through a simple cut on parallaxes (or
proper motions). Indeed, 657 million objects in Gaia DR3 have raw parallaxes
below 0.25 mas, the vast majority of which are of course stars in our Galaxy.
This is not to say that parallaxes, and moreover proper motions, are not
useful, however, and we do indeed make use of them in our classifications and
analyses.

Most of the extragalactic candidates we have identified are bundled into two
integrated tables in Gaia DR3, called qso_candidates and galaxy_candidates. As
their names make clear, the construction of these tables has been driven
primarily by the desire to be complete, rather than pure. Together these
tables contain around 11.3 million unique objects and have global purities of
50–70%, although they are significantly higher when we exclude the Galactic
plane, high density regions around clusters and galaxies, and the faintest
sources. These tables are nonetheless a significant improvement over the
gaia_source table, which has 1.8 billion objects and an extragalactic purity
of around 0.2%. Our rationale for producing completeness-driven integrated
tables is that it is easier for users to then select a sub-sample of purer
objects (according to their own criteria) from our integrated tables, than it
would be to find objects (in gaia_source) that had been removed from purity-
driven tables. In Sect. 8 we recommend how to extract a purer sub-sample
($\sim$96%) from the two integrated tables.

This paper is not the first to deal with classifying extragalactic objects
using Gaia data. Initial studies cross-matched Gaia positions to other
catalogues to analyse the properties of quasars and galaxies (e.g. Paine et
al., 2018; Souchay et al., 2019). Several studies have made cuts on the
astrometry (e.g. Heintz et al., 2018; Gaia Collaboration, 2018), sometimes
combined with classification using non-Gaia data (e.g. Fu et al., 2021), and
others have applied machine learning methods to a number of Gaia metrics (e.g.
Bailer-Jones et al., 2019) to identify extragalactic objects. Purer samples
should be attainable when combining Gaia data with more discriminatory data,
albeit at the loss of completeness if Gaia is the larger survey, and some
studies report good results here (e.g. Wu et al., 2021). Other studies have
used the Gaia data to characterise specific types of extragalactic object,
such as gravitational lenses (e.g. Krone-Martins et al., 2018; Delchambre et
al., 2019).

This paper is structured as follows. Section 2 summarizes the extragalactic
processing modules that deliver results in Gaia DR3 and Sect. 3 describes the
various tables that provide these results. Section 4 presents the properties
of the extragalactic objects, such as sky distributions, spectra, surface
brightnesses, and light curves. In Sect. 5 we provide some basic comparisons
between the results of the different modules, and in Sect. 6 we compare the
results to external surveys. In Sect. 7 we compute composite quasar spectra
from individual quasar spectra at a range of redshifts. Section 8 describes a
purer, and necessarily less complete, sub-sample of the integrated
extragalactic tables. We conclude in Sect. 9 with some suggested use cases.

Many more details on the topics discussed here can be found in the extensive
online documentation that accompanies this data
release.111https://gea.esac.esa.int/archive/documentation/GDR3/ We point in
particular to the table and field descriptions there. Several other release
papers provide details that are not in the documentation. These are Delchambre
et al. (2022) for the CU8 classification and redshift estimation modules,
Rimoldini et al. (2022) for the CU7 variability classifier and Carnerero et
al. (2022) for the resulting selection of Active Galactic Nuclei (AGN),
Ducourant et al. (2022) for the CU4 surface brightness profile analysis, and
Gaia Collaboration & Klioner et al. (2022) for the Gaia-CRF3 (Celestial
Reference Frame 3). Readers may also want to consult De Angeli et al. (2022)
for a description of the BP/RP spectrophotometry and Lindegren et al. (2021b)
for the astrometric (parallax and proper motion) processing (the latter
unchanged from Gaia EDR3).

##  2 Extragalactic processing modules

The modules in the Gaia data processing system that deal explicitly with
extragalactic objects are as follows. DSC and Vari classify Gaia objects using
supervised machine learning methods. Vari additionally provides
characterisations of the light curves. UGC (Unresolved Galaxy Classifier),
QSOC (Quasar Classifier), and OA (Outlier Analyser) analyse the results from
DSC, the first two computing redshifts. EO analyses the surface brightness
profiles of an input source list. We summarize these modules here, leaving
more detailed descriptions to the individual processing papers cited below. We
also include in our analysis the list of quasars identified for Gaia-CRF3.

Some sources, in particular galaxies, are partially resolved by Gaia. Their
two-dimensional structure – combined with the fact that Gaia observes sources
over a range of position angles – can induce a spurious (non-intrinsic)
photometric variability or an apparent astrometric variability, the latter
potentially being interpreted by the astrometric processing (Lindegren et al.,
2021b) as spuriously large parallaxes and proper motions. The DSC and Vari
modules take advantage of these spurious measurements to help them classify
extragalactic sources.

###  2.1 Discrete Source Classifier (CU8-DSC)

Figure 1: Colour–magnitude diagram (top) and colour–colour diagram (bottom) of
the DSC training data for the quasars (blue) and galaxies (orange) as well as
stars (black). The contours in each panel show the variation in source density
on a linear scale. The points are equal-sized random subsets of sources from
each class. There is significant overlap, in particular between stars and
quasars: in reality the former dominate by a factor of about a thousand, and
so overlap much more than is shown here. Plots for each class separately are
provided in the online documentation.

The Discrete Source Classifier uses the BP/RP spectrum together with the mean
G-band magnitude, the variability in this band, the parallax, and the proper
motion to classify each Gaia source probabilistically into five classes:
quasar; galaxy; anonymous (essentially single star); white dwarf; binary star.
DSC is trained empirically on Gaia data with labels for the quasar and galaxy
classes coming from Sloan Digital Sky Survey (SDSS) spectroscopic
classifications. The distributions of the training data in colour and
magnitude are shown in Fig. 1. The training data define the classes (see Sect.
6.2), so these are not the same class definition adopted by other modules that
contribute extragalactic source identifications to Gaia DR3. DSC comprises
three classifiers. Specmod uses the BP/RP spectrum only and gives results for
all five classes in DSC. Allosmod uses various photometric and astrometric
features and only gives results for quasars, galaxies, and single stars.
Specmod and Allosmod are nonetheless trained on a common set of data that has
complete data for both classifiers. One consequence of this is that Specmod is
also applied to some types of sources it was not trained on, for example
galaxies that lack measured parallaxes and proper motions. Combmod combines
the Specmod and Allosmod classification probabilities in a Bayesian manner to
give probabilities for all five classes (using the algorithm described in the
appendix of Delchambre et al. 2022). Probabilities from all three classifiers
are provided in the astrophysical_parameters table. DSC is described in more
detail in Delchambre et al. (2022) and in the online documentation.

DSC incorporates a global class prior that reflects the rareness of quasars
and galaxies. This makes it hard to achieve a high purity even for a good
classifier. For example, if only one in every thousand sources were
extragalactic, then even if a classifier had a 99.9% accuracy, the resulting
sample would only be around 50% pure. For this reason one must report results
not on a balanced validation set, but on one that reflects this prior.222In
practice we can use a validation set with more convenient class fractions, and
then adjust the confusion matrix to reflect the prior, as explained in Sect.
3.4 of Bailer-Jones et al. (2019).

In addition to posterior probabilities, DSC also provides two class labels.
The first, classlabel_dsc, is assigned the name of the class that achieves the
highest posterior probability in Combmod that is greater than 0.5. If none of
the output probabilities are above 0.5 then this class label is unclassified.
This tends to produce a complete but impure sample of objects when we properly
account for extragalactic rareness. The analyses in Delchambre et al. (2022)
and Bailer-Jones (2021) using SDSS spectroscopically-confirmed objects shows a
completeness for quasars and galaxies objects of over 90%, but a global purity
of only about 20–25%. For Galactic latitudes above 11.5∘ the purities increase
to 41%. Additional filtering increases this further (see Sect. 8). The second
class label, classlabel_dsc_joint defines a purer set of quasars and galaxies,
and is assigned by requiring both Specmod and Allosmod probabilities to be
above 0.5 for the corresponding class. This gives completenesses of 38% on
quasars and 83% on galaxies, and purities on both classes of 63%. For Galactic
latitudes above 11.5∘ the purities increase to about 80%.

###  2.2 Quasar Classifier (CU8-QSOC)

The Quasar Classifier module (QSOC) estimates the redshift of sources
classified as quasars by DSC-Combmod using their BP/RP spectra. For this
selection, QSOC uses a very loose cut on the DSC quasar probability,
classprob_dsc_combmod_quasar $\geq 0.01$. This prioritizes completeness at the
expense of purity to ensure that most of the objects that are suspected to be
quasars are given a redshift estimate. The QSOC redshifts are inferred with a
chi-square approach, whereby the BP and RP spectra are compared to a composite
quasar spectrum taken at various trial redshifts in the range $0\lesssim
z\lesssim 6$. The composite spectrum is built upon a semi-empirical library of
quasars from the SDSS DR12Q sample (Pâris et al., 2017). Each SDSS spectrum is
first extrapolated to the wavelength range covered by BP/RP before being
converted into a BP/RP spectrum using the available instrument model. More
details of the algorithm can be found in Delchambre et al. (2022). In addition
to the best point estimate of the redshift, QSOC also estimates lower and
upper confidence intervals, redshift_qsoc_lower and redshift_qsoc_upper, which
are the $15.9\%$ and $84.1\%$ quantiles of a log-normal distribution. The
module also sets various processing flags in flags_qsoc, reflecting potential
issues and/or degeneracies that may occur during the prediction phase.

###  2.3 Unresolved Galaxy Classifier (CU8-UGC)

The Unresolved Galaxy Classifier (UGC) estimates the redshift of sources
classified as galaxies by DSC-Combmod with probability
classprob_dsc_combmod_galaxy $\geq 0.25$. UGC uses the BP/RP spectrum together
with a supervised machine learning algorithm, the Support Vector Machine (SVM)
(Cortes & Vapnik, 1995; Chang & Lin, 2011). A regression model (t-SVM) is
trained on a set of 6000 sources selected from galaxies in the SDSS DR16
archive (Ahumada et al., 2020; Blanton et al., 2017) that are cross-matched to
sources observed by Gaia. The BP/RP spectra and the SDSS redshifts of the
sources in this set are used as training input and output, respectively. The
SDSS galaxies were selected to have redshifts in the range $0\leq z\leq 0.6$
and magnitudes $17\leq G\leq 21$. Additional conditions were applied to
specific parameters that influence the quality of the observed spectra. A test
set of 250 000 galaxies, selected in a similar manner as the training set, was
used to estimate the performance of the model, as reported in Delchambre et
al. (2022). This set was also used to estimate statistical uncertainties of
the redshift predictions in redshift bins of width 0.02. The bias – the mean
difference between predicted and observed redshifts – was found to be $-0.006$
with a root mean squared error of $0.039$ for the entire redshift range
$0.0\leq{}z\leq{}0.6$. However, the uneven distribution of redshift and
magnitude causes the performance to be better for lower redshifts than for
higher ones. For each estimated redshift_ugc we further determine the lower
and upper prediction level, redshift_ugc_lower and redshift_ugc_upper,
corresponding to the bias and the $1\sigma$ error of the SVM model in the
closest bin. See the online documentation for more details.

###  2.4 Outlier Analysis (CU8-OA)

The Outlier Analysis (OA) module was originally intended to analyse those
sources that receive low classification probabilities for all DSC classes. As
DSC-Combmod tends to give rather extreme probabilities – near to 0.0 or 1.0 –
we used OA to analyse all sources that have all DSC-Combmod probabilities less
than 0.999. This corresponds to 56 million sources. OA uses a Self-Organizing
Map (Kohonen, 1982), an unsupervised neural network that groups together
similar data on a two-dimensional grid of neurons, in our case $30\times 30$.
The data here are the BP/RP spectra. From this we compute a prototype spectrum
of each neuron as the mean of all spectra assigned to that neuron. We further
compute various statistics for each neuron, such as the mean $G$, $G_{\rm
BP}$, $G_{\rm RP}$, parallax, and Galactic latitude. We also compute a quality
index that is based on the intra-neuron distance distribution; it takes seven
discrete values from 0 to 6, where 0 represents the best quality neurons and 6
the poorest ones. The method of allocation to these is described in the online
documentation. Finally, we compute a class label for each neuron by finding
the best match between its prototype and a series of labelled templates,
although neurons with quality index 6 are not assigned a label. This
information is given in the oa_neuron_information and oa_neuron_xp_spectra
tables, and an interactive visualization tool that can explore these tables is
available (Álvarez et al., 2021).

###  2.5 Variability (CU7)

Extragalactic objects can also be identified via their photometric
variability. Galaxies with active nuclei show variability in their accretion,
such as in Seyfert galaxies and quasars, and in the case of blazars
variability can be intrinsic or geometrical, related to a relativistic plasma
jet directed towards us.

Using a supervised classification method Vari-Classification described in
Rimoldini et al. (2022), we identified 1.0 million Active Galactic Nuclei
(AGN) and 2.5 million galaxy candidates from the variability of the Gaia light
curves. Epoch photometry in the $G$, $G_{\rm BP}$, and $G_{\rm RP}$ bands are
published for AGN candidates, and for those galaxies that are part of the Gaia
Andromeda Photometric Survey (GAPS; Evans et al., 2022) or that might be
misclassified as real variables in Gaia DR3 (and so published in one of the
variability tables). Indeed, the apparent variability of galaxies in the Gaia
data is mostly an artefact of their extension combined with the Gaia on-board
detection algorithm and scanning law (see Sect. 4.4.2) and so does not justify
the release of their time series (which are meant only for genuine variable
objects). Nevertheless, the characteristics of these artificial brightness
variations made it possible to identify galaxies as if they were variable
objects. Light curve statistics for all sources with light curves are
published in the vari_summary table.

Further analysis and characterisation of the variable AGN classifications (by
the module Vari-AGN) led to a higher purity selection of about 872 000 objects
(Carnerero et al., 2022), whose AGN-specific metrics are published in the
vari_agn table, and repeated in the qso_candidates table (see Sect. 3). The
purity of this AGN sample was estimated to be about 95%. The galaxy sample in
galaxy_candidates is perhaps even purer, estimated at 99%, although with a
lower completeness at around 40% (Rimoldini et al., 2022).

###  2.6 Surface brightness profile (CU4)

A source is recorded by Gaia only if the on-board video processing unit
determines its light profile to be sufficiently steep at its centre (Gaia
Collaboration et al., 2016). While this is intended to accept only point
sources, it does pick up some extended objects (see section 2). The resulting
selection function has been assessed theoretically by de Bruijne et al. (2015)
and de Souza et al. (2014).

The CU4 surface brightness profile module attempts to reconstruct the two-
dimensional light profile of extragalactic sources in the following way (see
Ducourant et al. 2022 for more details). Gaia scans each source at a range of
transit angles during the course of its mission. These observations are mainly
one-dimensional (nine one-dimensional Astro Field (AF) windows plus the two-
dimensional Sky Mapper (SM) window), but after a sufficient number of
transits, most of the surface of the source has been covered by these
transits. The CU4 module attempts to reproduce these observed windows from a
large number of simulations of images of galaxies, each with different shape
parameters from which Gaia-like windows are extracted. The parameters that
produce the best fit to the observations are taken as the profile of the
source.

The module is only applied to a pre-selected list of extragalactic sources
(summarized below). Fits are made for the flux profiles for two types of
objects: quasars and their decomposition into quasar and host galaxy; and
galaxies.

Figure 2: Comparison of the flux collected in the AF and SM windows in the
Gaia focal plane for quasars (with and without a detected host galaxy in Gaia)
and for galaxies. Objects with an extension detectable by Gaia lie above the
turquoise diagonal of quasars with no host galaxy.

For the quasars, the module first compares the mean integrated flux of the
source in the small AF window (707 mas x 2121 mas) to the mean integrated flux
in the large SM window (4715 mas x 2121 mas) (Gaia Collaboration et al.,
2016). A larger flux in the SM window is interpreted as a detectable host
galaxy, and the surface brightness profile is fit as a combination of an
exponential circular profile for the central active nucleus and a Sérsic
profile (including ellipticity and position angle) for the host galaxy (see
Fig. 2). The surface brightness profile parameters of the host galaxy are
produced only when there is no other source present within 2.5″, and only for
those sources with a half light radius smaller than 2.5″, in order to avoid
too large an extrapolation of the profile and so to increase the reliability
of the parameters.

For the galaxies, all the objects processed exhibit flux excess in the SM
window when compared to the mean flux in AF window (see Fig. 2), indicating
that these sources are clearly extended. Two independent surface brightness
profiles are fit for all objects: a Sérsic and a de Vaucouleurs profile.

The pre-defined list of extragalactic sources for these two types of
processing was determined as follows. For quasars, several major catalogues of
quasars and candidates were compiled: AllWISE (Assef et al., 2018; Secrest et
al., 2015), HMQ (Flesch, 2015), LQAC3 (Souchay et al., 2015), SDSS-DR12Q
(Pâris et al., 2017), ICRF2 (Ma et al., 2009), and a selection of unpublished
classifications of Gaia DR2 quasars based on photometric variability
(Rimoldini et al., 2019). Together this gave a list of 1.4 million sources. Of
these, we retained for analysis in Gaia DR3 a subset of $1\,103\,691$ sources,
each of which has at least 25 Gaia observations that together cover at least
86% of the surface area of the source. For the galaxies, a machine learning
analysis of Gaia DR2 combined with the WISE survey (Cutri & et al., 2012) was
used to identify 1.9 million galaxy candidates (Krone-Martins et al., 2022).
The same filtering of sources as for the quasars reduced this to 914 837
galaxies to be analysed.

###  2.7 Gaia-CRF3 (CU3)

One of the outputs of the astrometric solution in Gaia DR3 is the selection of
a set of sources whose positions and proper motions define the celestial
reference frame of Gaia DR3, called Gaia-CRF3. These correspond to sources
cross-matched between Gaia and several external quasar catalogues, and
selected according to specific quality metrics. The procedure to define this
source list is described in Gaia Collaboration & Klioner et al. (2022) and
Gaia Collaboration et al. (2021). This source sample also represents an
official realisation of the International Celestial Reference System (ICRS) at
optical wavelengths, as acknowledged by Resolution B3 of the IAU (2021).

##  3 Gaia DR3 tables with extragalactic content

The extragalactic content of Gaia DR3 is provided through a number of tables
and fields. These list, among other measures, the outputs of the modules
described in the previous section.

The gaia_source table provides two dedicated flags (in_qso_candidates and
in_galaxy_candidates) that indicate the presence of a given source in the
respective tables of the same name (described below). It also lists the DSC-
Combmod probabilities for the quasar and galaxy classes (Sect. 2.1). The table
astrophysical_parameters lists all the parameters produced by the modules in
CU8, namely DSC, QSOC, UGC, and OA. Further results from OA (Sect. 2.4) are
provided in the oa_neuron_information table. These tables contain all sorts of
objects, not just (candidate) extragalactic ones. The tables
vari_classification_result and vari_agn provide information on AGN identified
through the photometric light-curves (Sect. 2.5). As a complement to the Gaia-
CRF3 table carried over from Gaia-EDR3 (table agn_cross_id), there is a new
table gaia_crf3_xm in Gaia DR3 that provides the complete cross-match
information between the Gaia-CRF3 sources and the external catalogues in which
they were identified (Gaia Collaboration & Klioner et al., 2022).

###  3.1 Integrated tables: qso_candidates and galaxy_candidates

In addition to the above tables, two integrated tables -- qso_candidates and
galaxy_candidates \-- are a compilation of the results from all processing
modules that have classified or analysed extragalactic objects. While some of
their columns are copies of information available in the above-mentioned
tables, the rest are provided exclusively through these integrated tables.
This is the case for the DSC class labels and the redshifts stemming from QSOC
and UGC, as well as the results from the surface brightness profile analysis.
These two integrated tables are limited to sources that are more likely to be
extragalactic, and have been selected using a number of different selection
rules that are defined in the online documentation. Below we provide just a
summary of these rules.

The qso_candidates table is constructed as follows.

  * •

Sources for which the quasar class probability was larger than 0.5 for any of
the three DSC classifiers (Specmod, Allosmod, Combmod -- see Sect. 2.1) are
included. In addition to this, QSOC sources with reliable redshifts were also
added (Sect. 2.2). This reliability is determined from a combination of rules
involving quality flags and Gaia photometry thresholds (for details see
Delchambre et al. 2022).

  * •

Sources based on the analysis of photometric light curves (Vari-
Classification, Sect. 2.5) were selected when their class label was set to
AGN. This class label is defined in Rimoldini et al. (2022). Almost all of
these sources are also part of the Vari-AGN sample, but a handful are not and
they have also been added to the integrated quasar table.

  * •

Quasars for which the surface brightness profile was analysed as described in
Sect. 2.6 were included provided the presence or not of a host galaxy could be
assessed with sufficient confidence. An ancillary table qso_catalogue_name
provides the name of the external catalogues that were used to select the
sources that entered this pipeline.

  * •

All sources used to define the Gaia-CRF3 (provided in table agn_cross_id, see
Sect. 2.7 and Gaia Collaboration & Klioner et al. 2022) are in the quasar
table, and a dedicated flag, gaia_crf_source, identifies them.

  * •

OA does not contribute any additional sources to the table. We simply add
class labels from OA to sources that are included by the above selections.
These labels are not necessarily limited to be extragalactic source labels.

The galaxy_candidates table is constructed as follows.

  * •

Sources for which the galaxy class probability was larger than 0.5 for any of
the three DSC classifiers (Specmod, Allosmod, and Combmod -- see Sect. 2.1)
are included. In addition to this, UGC sources with reliable redshifts were
also added (Sect. 2.3). The reliability is determined by a combination of two
sets of rules, one concerning the quality of the ${\rm BP/RP}$ spectrum of the
source, the other involving the comparison of outputs from three models
estimating the redshift (for details see Delchambre et al. 2022).

  * •

Sources identified by Vari-Classification (Sect. 2.5) were selected if their
class label was set to GALAXY. For a description of how this class label was
defined, see Rimoldini et al. (2022).

  * •

Galaxies for which the surface brightness profile was analysed as described in
Sect. 2.6 were included if the light profile parameters could be derived with
sufficient quality. In complement to this, an ancillary table
galaxy_catalogue_name provides the name of the external catalogues that were
used to select the sources that entered this pipeline. In Gaia DR3 the only
applicable catalogue is that described in Krone-Martins et al. (2022).

  * •

As for the qso_candidates table, OA does not contribute additional sources. It
only provides additional columns, which are filled just for those sources that
were processed by OA.

The source lists according to the above selection criteria were concatenated
into two lists, one for the qso_candidates table and one for the
galaxy_candidates table. A complete list of the parameters (table columns)
available in each table is given in the online documentation. Columns are
filled for all sources regardless of how they are selected; thus a source may
have a DSC probability that does not meet the above DSC selection criteria,
for example (see Table 1). Not all parameters are available for all sources,
as not all sources were treated by all modules. There are 6 649 162 sources in
the qso_candidates table and 4 842 342 in the galaxy_candidates table. This
large number of sources is mostly due to the selection rules of the DSC
module, which favour completeness over purity (see section 2.1 and Delchambre
et al. 2022). Users should therefore be aware that there is significant
stellar contamination in these tables. For DSC this can be addressed using the
classlabel_dsc_joint field. We address more generally how to build purer sub-
samples in Sect. 8. There are 174 146 sources in common between the two
tables, and their union contains 11.3 million sources.

Table 1 gives an overview of how many sources from each module contribute to
the integrated tables. Source overlaps between the modules within each table
are shown in Tables 2 and 3, and graphically represented in the Venn diagrams
in Figs. 3 and 4. Information about the distribution of the parameters
featured in the tables is provided in the next section.

Table 1: Number of sources from each of the extragalactic processing modules contributing to the qso_candidates and galaxy_candidates tables (second column), or to the set of parameters featured for the respective modules (third column). The difference between the two columns indicates the number of sources where parameters are provided despite the sources not being eligible according to the selection rules of that module. A given source can be contributed by more than one module.  Module | Selected | Featuring
---|---|---
| sources | parameters
qso_candidates | 6 649 162 |
DSC | 5 543 896 | 6 647 511
QSOC | 1 834 118 | 6 375 063
Vari-Classification | 1 035 207 | 1 122 361
Vari-AGN | 872 228 | 872 228
Surface brightness | 925 939 | 1 084 248
Gaia-CRF3 | 1 614 173 | 1 614 173
OA | N/A | 2 803 225
galaxy_candidates | 4 842 342 |
DSC | 3 726 548 | 4 841 799
UGC | 1 367 153 | 1 367 153
Vari-Classification | 2 451 364 | 2 477 273
Surface brightness | 914 837 | 914 837
OA | N/A | 1 901 026
Table 2: Source overlaps between the modules contributing to the qso_candidates table. See text for details about the module names.  Module | Surface | Vari- | Vari-AGN | OA | QSOC | DSC
---|---|---|---|---|---|---
| brightness | classification |  |  |  |
Gaia-CRF3 | 819 541 | 833 755 | 722 211 | 550 807 | 672 454 | 1 288 845
Surface brightness |  | 513 084 | 483 786 | 278 078 | 458 241 | 748 584
Vari-classification |  |  | 872 184 | 245 318 | 477 971 | 944 148
Vari-AGN |  |  |  | 186 836 | 442 436 | 814 315
OA |  |  |  |  | 896 173 | 2 085 554
QSOC |  |  |  |  |  | 1 097 229
Table 3: As 2 for modules contributing to the galaxy_candidates table.  Module | Vari- | UGC | OA | DSC
---|---|---|---|---
| classification |  |  |
Surface brightness | 634 550 | 388 552 | 434 880 | 530 411
Vari-Classification |  | 972 929 | 1 070 865 | 1 529 594
UGC |  |  | 190 583 | 1 351 222
OA |  |  |  | 840 409
Figure 3: Quadruple Venn diagram for contributions to the qso_candidates table
from DSC, the Surface brightness sample, Vari-Classification, and Gaia-CRF3.
Figure 4: Quadruple Venn diagram for contributions to the galaxy_candidates
table from DSC, the Surface brightness sample, Vari-Classification, and UGC.

To estimate the overall purity of the integrated tables, we must be aware that
modules with different purities can contribute the same source to a table. The
estimation can be simplified, however, when we consider that all modules
except DSC have similar high purities. Specifically, for the qso_candidates we
assume that the modules other than DSC have an average purity of 96%, compared
to a global DSC purity of 24%. From Fig. 3 we see that 4.1 million sources are
contributed only by DSC, with the remaining 2.6 million contributed by the
other modules. This gives an overall purity of the qso_candidates table of
52%. In a similar way, we estimate the overall purity of the galaxy_candidates
to be 69%. We show how to obtain a purer sub-sample in Sect. 8.

##  4 Basic properties

###  4.1 Parameter distributions

####  4.1.1 Integrated tables

Figure 5: Galactic sky distribution of all the sources in the qso_candidates
table (left) and galaxy_candidates table (right). The plot is shown at
HEALpixel level 7 (0.210 sq. deg.) in Hammer--Aitoff projection. The colour
scale, which is logarithmic, covers the full range for each panel, so is
different for each panel.  Figure 6: G-band magnitude distribution of all
objects in the qso_candidates (blue) and galaxy_candidates (orange) table on a
logarithmic scale. The brightest known quasar (3C273 -- source_id
3700386905605055360) has a G magnitude of 12.8.

Figure 5 shows the sky distribution on a logarithmic density scale of all
sources in the qso_candidates and galaxy_candidates tables. As already noted,
there is considerable contamination in these due to misclassifications and the
completeness-driven nature of the tables (i.e. the absence of filtering in
some modules). This is apparent from the overdensities around the Large and
Small Magellanic Clouds (LMC and SMC). If we exclude generous regions around
the LMC and SMC (defined in appendix B), then the number of sources in the
qso_candidates table drops to 3.95 million (59% of the full table) and the
number of sources in the galaxy_candidates table drops to 4.67 million (96% of
the full table). Some patterns are also an artefact of the use of input lists
for some of the modules. Many of these sources are also faint, with poorer
data in Gaia DR3, as can be seen in Fig. 6. There is also a small fraction of
sources that are too bright to be genuine quasars or galaxies, which is an
inevitable consequence of even a small misclassification probability and
limited filtering.

Figure 7: Colour--colour diagram (top) and colour--magnitude diagram (bottom)
for all sources in the qso_candidates table (blue) and galaxy_candidates table
(orange). The contours show density on a linear scale. The points are a random
selection of 10 000 sources for each class.

The Gaia colour--colour diagram (CCD) and colour--magnitude diagram (CMD) are
shown in Fig. 7. Quasars and galaxies separate quite well, but recall that
Gaia observes primarily those galaxies with point-source like cores. What is
not seen in these diagrams is the distribution of the stars, which outnumber
true quasars and galaxies by a factor of 500--1000 in Gaia DR3, and which make
it hard to identify extragalactic objects based only on their Gaia colours.

####  4.1.2 DSC subset of the integrated tables

Figure 8: Colour--colour diagram for sources in the qso_candidates table,
excluding regions around the LMC and SMC. The left column shows sources with
classlabel_dsc = quasar (2.77 million sources), the right column shows sources
with classlabel_dsc_joint = quasar (the purer subset, 0.52 million sources).
These numbers refer to the number of sources plotted, which are those that
have all Gaia bands. The upper panel shows the mean DSC-Combmod probability
for the quasar class (the field classprob_dsc_combmod_quasar). The lower panel
shows the density of sources on a log scale relative to the peak density in
that panel (densities 1000 times lower than the peak are not shown).

Figure 9: As Fig. 8, but for sources in the galaxy_candidates table. There are
3.24 million sources with classlabel_dsc = galaxy and 0.25 million sources
with classlabel_dsc_joint = galaxy (in both cases excluding the regions around
the LMC and SMC, and requiring all three Gaia bands).

DSC is the dominant contributor to the qso_candidates and galaxy_candidates
tables, so we look here at two subsets for each table defined by the DSC class
labels (Sect. 2.1). The first is selected by classlabel_dsc, which gives 5 243
012 quasars in the qso_candidates table (class quasar) and 3 566 085 galaxies
in the galaxy_candidates table (class galaxy). Through comparison to SDSS
spectroscopic classifications, and accommodating for the significant
contamination by stars, we estimate these samples to have rather low purities
of 24% and 22% respectively (see Bailer-Jones 2021, summarized in Delchambre
et al. 2022, and Sect. 6.2 below). The second subset is the purer one
identified using classlabel_dsc_joint, which gives 547 201 quasars in the
qso_candidates table and 251 063 galaxies in the galaxy_candidates table.
These two sets are estimated to have higher purities of 62% and 64%
respectively, and of 79% and 82% respectively if we look only at higher
latitudes ($|b|>11.54^{\circ}$).

Figure 8 shows the Gaia colour--colour diagrams for quasars in the
qso_candidates table according to these two subsets. The upper panels show the
DSC-Combmod probabilities. In the upper left panel we see that there are
sources far away from the main clump of quasars, but the lower panel reveals
that there are very few of them. These are all removed in the
classlabel_dsc_joint = quasar set (right column), which shows only high
Combmod probabilities. Figure 9 shows the corresponding colour--colour
diagrams for the galaxy_candidates table. Again we see how the set defined by
classlabel_dsc_joint = galaxy has a tighter distribution and higher Combmod
probabilities than the less pure set defined by classlabel_dsc = galaxy.
Similar figures showing the quasar and galaxy populations together are shown
in Delchambre et al. (2022). These also show that use of the joint label
preferentially removes fainter, lower signal-to-noise sources, as these are
less likely to get a high probability classification in both Specmod and
Allosmod.

One thing to bear in mind is that Specmod and Allosmod do not deal with
identical sets of sources, because these classifiers require different input
data. In particular, Allosmod requires parallaxes and proper motions, that is
5p or 6p astrometric solutions (see Lindegren et al. 2021a for the definition
of these solutions). Galaxies often only get 2p solutions (no parallax or
proper motion) on account of their physical extent. Of the 3 566 085 million
sources in the galaxy_candidates table with classlabel_dsc = galaxy, 3 367 211
have all three photometric bands, but of these, only 1 015 462 have parallaxes
and proper motions and so can be classified by Allosmod (these numbers are for
the whole sky, so including the LMC and SMC). As classlabel_dsc_joint can only
be set to galaxy when Allosmod results are present, the change in the
distribution we see in Fig. 9 for the two class labels is partially due to
this. Plots in Delchambre et al. (2022) show the change when only considering
the subset with 5p or 6p solutions. Most quasars, in contrast, do have 5p or
6p solutions: Of the 5 243 012 sources in the qso_candidates with
classlabel_dsc = quasar, 5 086 531 have all three photometric bands, of which
4 815 212 have parallaxes and proper motions.

Because DSC is not the only contributor to the integrated tables, some of the
sources in these tables have DSC class labels that are not the class of the
table. In the qso_candidates table, 156 970 sources have classlabel_dsc set to
galaxy, and 12 302 have classlabel_dsc_joint set to galaxy. In the
galaxy_candidates table, the numbers with these two classlabels set to quasar
are 12 933 and 234 respectively.

###  4.2 BP/RP spectra

Gaia observes all of its targets with the low resolution
($30\leq\lambda/\Delta\lambda\leq 100$) ${\rm BP/RP}$ slitless spectrograph
(Carrasco et al., 2021). 1.6 billion of these were used by DSC-Specmod for
classification (section 2.1; Delchambre et al. 2022), but only a fraction of
these are published in Gaia DR3. Spectra for all sources brighter than
$G=17.35$ mag with at least 15 retained observations in each of BP and RP are
published in Gaia DR3, amounting to 220 million sources. This includes few
extragalactic sources, so a small set of these were added. In total, ${\rm
BP/RP}$ spectra of 163 000 quasar candidates and 26 500 galaxy candidates in
the integrated tables are published in Gaia DR3. Of these, 119 000 and 12 600
respectively are in the purer sub-samples defined in Sect. 8.

As described in De Angeli et al. (2022), spectra are published as a set of
coefficients of basis functions, from which spectra at arbitrary samplings can
be produced using a published software tool. Internal to CU8, the spectra were
sampled using the tool SMS-gen (Creevey et al., 2022), which is what we used
to produce the spectra shown in this section. In all cases the spectra are the
mean (epoch-averaged) spectra over a time span of up to 34 months.

####  4.2.1 Quasars

Figure 10: Distribution of the BP flux (left) and RP flux (right) as sampled
by SMS-gen (Creevey et al., 2022) of 42 944 quasars published in Gaia DR3 that
have spectroscopically confirmed redshifts in the Milliquas 7.2 quasar
catalogue of Flesch (2021) (type = Q). Dotted lines show the dominant quasar
emission lines. Spectra are individually normalized in order to have a maximum
flux of 1.0 and are then averaged in redshift bins of 0.01, with the inverse
variance of the sampled fluxes used as the weight during the computation of
the mean.

Figure 10 shows the ${\rm BP/RP}$ spectra for 42 944 quasars with published
${\rm BP/RP}$ coefficients (field has_xp_continuous = true in gaia_source),
classprob_dsc_combmod_quasar $>0.01$ and spectroscopically confirmed redshift
in the Milliquas 7.2 quasar catalogue of Flesch (2021) (type = Q). A search
radius of 1$\arcsec$ was used to match the Gaia sources to their Milliquas
counterparts, leading to a redshift coverage of $0.052\leq z\leq 4.358$. The
cut on the DSC Combmod quasar probability ensures that obvious stellar
contaminants contained in our cross-match are discarded. The median magnitude
of the sources in Figure 10 is $G=18.53$ mag. Gaia observes much fainter
quasars, but the ${\rm BP/RP}$ spectra of many of these will only be released
in Gaia DR4. While we clearly see common quasar emission lines in this
averaged plot, they are not necessarily visible in the low signal-to-noise
ratio (S/N) spectra of individual faint quasars. Similarly, wiggles that are
an artefact of the Hermite spline representation of the ${\rm BP/RP}$ spectra
(De Angeli et al., 2022) tend to lower the contrast of these emission lines
compared to the continuum. These wiggles smooth out faint spectral features,
and can be confused with emission lines, as both have comparable strength in
low S/N spectra. Typically, though, the strongest spectral features --
Ly$\alpha$, C iv, H$\beta$, and H$\alpha$ \-- are retained in $G<20$ mag
spectra. We also see in Fig. 10 that regions at wavelengths below 430 nm and
above 650 nm in BP, and below 630 nm and above 950 nm in RP, contain little
flux: spectral features in these regions generally have low S/N, complicating
their detection by the DSC and QSOC algorithms.

####  4.2.2 Galaxies

Figure 11 shows four representative spectra of galaxies as observed by Gaia
(top row) and their corresponding SDSS spectra (bottom row). The first SDSS
spectrum on the left shows only absorption lines, suggesting an early type
galaxy with little or no star formation activity (the few spikes are caused by
cosmic rays). These lines are barely detectable, if at all, in the low-
resolution ${\rm BP/RP}$ spectrum. The two middle spectra show strong emission
lines characteristic of active star formation. The strongest is the H$\alpha$
emission with [N II] lines on either side. This set of three lines is
unresolved in the RP spectrum where it merges into a single and wide emission
feature. Similarly, in the BP spectrum the H$\beta$ and [O III] emission lines
are merged into another wide peak. The last spectrum on the right is
classified as a ’GALAXY AGN’ in SDSS. The corresponding ${\rm BP/RP}$
spectrum, due to the much lower resolution -- and the already mentioned
wiggles -- shows much less prominent features.

Figure 11: Galaxy spectra. Top row: Representative mean BP and RP Gaia spectra
for four galaxies. Bottom row: The spectra for the same galaxies as observed
with the SDSS-BOSS spectrograph (the SDSS class and subclass, if defined, are
shown).

###  4.3 Surface brightness profiles

####  4.3.1 Quasars

The majority of the $1\,103\,691$ quasars analysed in terms of surface
brightness lie in the diagonal of Fig. 2. These sources are considered point-
like with no host galaxy detectable by Gaia. A group of 64 498 exhibit a clear
extension, indicative of a host galaxy, as evidenced by larger fluxes in the
SM window than in the AF window (Sect. 2.6). For these sources the flag
host_galaxy_detected = true is set. Among these, a robust solution from the
fitting process was derived for 15 867 sources and their surface brightness
profile is given in the catalogue. The flag host_galaxy_flag indicates the
outcome of the fitting process for all sources considered. Values of 1 and 2
are good fits, indicating detection of a host galaxy. 3 indicates that no host
could be found, whereas 4 is a poor fit. Sources with host_galaxy_flag = 5 or
6 show no evidence of a host galaxy in our analysis, due to non-convergence of
the algorithm or the presence of a close neighbour, respectively.

Figure 12:  Distribution in Galactic coordinates (Hammer--Aitoff projection)
of the quasars processed by the surface brightness profile module. Blue points
are quasars with a host galaxy detected (host_galaxy_detected = true) and
turquoise points are those without a host galaxy.

Figure 12 shows the spatial distribution on the sky of the $1\,103\,691$
quasars analysed. The coverage is inhomogeneous due to the limited sky
coverage of the catalogues that constitute the quasar input list (Sect. 2.6)
but it also reflects the scanning law of Gaia, as we only analyse sources that
have at least 25 focal plane transits. The empty zones correspond either to
the Galactic plane or to zones of lower frequency of scanning in Gaia DR3.

The distribution of the Sérsic index for all the quasars has a mode at 0.9 and
a mean of 1.9. These values are consistent with quasars hosted by galaxies
with disk-like light profiles, in agreement with a recent study of the surface
brightness of host galaxies from the Hyper Suprime-Cam Subaru Strategic
Program (Li et al., 2021).

The distribution of position angles of host galaxies is roughly uniform, as
expected, although there is a small excess at around 90∘. These are sources
with negligible ellipticity for which the position angle is meaningless. In
such cases, our fitting algorithm favours a 90∘position angle. The same is
true for the galaxy sample discussed in the next section.

Figure 13: Normalized distribution of the redshifts from Milliquas v7.2aa
(Flesch, 2021) of quasars that were analysed for surface brightness profiles.
Blue shows the 2000 quasars for which a host galaxy was detected by Gaia, and
turquoise the remaining 224 000 quasars for which no host galaxy was detected.

226 160 of the quasars processed have a spectroscopic redshift listed in
Milliquas 7.2 (Flesch, 2021) (selection TYPE = Q). 2084 of these have a host
galaxy detected by Gaia. Figure 13 shows the distribution of these redshifts.
As expected, the quasars with a host galaxy have small redshifts (mean z=0.54)
whereas those without a visible host galaxy have larger redshifts (mean
z=1.71). In a few cases the host is detected for larger redshifts. These
sources are usually very faint (G$>$20 mag) and suffer either from
uncertainties in the light profile fit or in the redshift measurement. The
host galaxies resolved by Gaia have an effective radius (encompassing half of
the total light) distribution with a peak at around 800 mas.

####  4.3.2 Galaxies

The surface brightness profile module processed 914 837 galaxies. We see from
Fig. 2 that all of these have a clear spatial extension.

The distribution of the effective radius of the de Vaucouleurs profile as
measured by Gaia is shown in Fig. 14 as a function of the Gaia redshifts
(given by redshift_ugc in table galaxy_candidates). The redshifts are all
below about 0.5, with a mean value of 0.16. As expected, the closer a source
is to us, the larger its effective radius. There is a slight accumulation of
effective radii at 8000 mas, which corresponds to the bound of the parameter
search domain, with the results that for larger galaxies the radius would
remain at 8000 mas.

Figure 14: Distribution of the effective radius (de Vaucouleurs profile) of
galaxies processed by the surface brightness profile module as function of the
redshifts measured by Gaia (redshift_ugc).  Figure 15: Distribution in
Galactic coordinates (Hammer-Aitoff projection) of the galaxies processed by
the surface brightness profile module. The colours show the density on a
linear scale.

Figure 15 shows the distribution of these galaxies on the sky. As with the
quasars in the previous section, we see an uneven distribution due primarily
to the required minimum number of observations.

The distribution of the Sérsic index peaks at around 4.5, which is consistent
with the fact that the on-board detection algorithm favours elliptical types
(de Souza et al., 2014). A few thousand galaxies have a Sérsic index below 2,
indicative of disk galaxies. A visual inspection of a fraction of these
reveals that most of them exhibit a compact bright bulge. The effective radius
of the Sérsic profile has a peak value around 1800 mas and a de Vaucouleurs
radius of around 1000 mas, which is typical of sources with a mean redshift of
0.13.

The ellipticities derived from Gaia exhibit a peak value around 0.25. This is
more or less what is expected from the projection of oblate ellipsoids
(representative of elliptical) onto the plane of the sky and is also observed
in other surveys, such as Padilla & Strauss (2008).

###  4.4 Light curves

####  4.4.1 AGN

Gaia DR3 includes about a million variable AGN candidates in the
vari_classifier_result table, which were selected mainly on the basis of their
variability properties. For these, the epoch photometry in the $G$, $G_{\rm
BP}$, and $G_{\rm RP}$ bands is published in the light_curve datalink table. A
complete description of the selection methods can be found in Rimoldini et al.
(2022), and are summarized below. More restrictive criteria were applied to
achieve the higher purity sample comprising 872 228 candidates in the vari_agn
table (Sect. 2.5), the characteristics of which are analysed in Carnerero et
al. (2022).

Figure 16: Light curves in the $G$ (black dots), $G_{\rm BP}$ (blue
triangles), and $G_{\rm RP}$ (red diamonds) bands of some variable AGN
sources. From top to bottom: a) the type 1 Seyfert galaxy PG 0921+525
(source_id 1019788071166861952); b) the blazar CTA 102 (source_id
2730046556694317312) caught during its historical 2016--2017 outburst; c) the
quasar B2 0945+22 (source_id 640411921988216576).

Of the one million $G$-band light curves of the variable AGN, 90% contain
between 20 and 244 focal plane transits covering 795 to 1038 days (after
applying time series filters described in Sect. 10.2 of the online
documentation). On average they have 39 focal plane transits over 925 days,
which is sufficient to follow the long-term variability of most AGN. Figure 16
shows the light curves in the $G$, $G_{\rm BP}$, and $G_{\rm RP}$ bands of
three sources belonging to different AGN classes: a) the type 1 Seyfert galaxy
PG 0921+525; b) the blazar CTA 102, which was observed during its historical
2016--2017 maximum (Raiteri et al., 2017), resulting in the most variable
object of the sample; c) the quasar B2 0945+22.

Photometrically-variable AGN candidates from supervised classification were
verified and further down-selected by a series of filters that use Gaia-CRF3
(Gaia Collaboration & Klioner et al., 2022) as a reference sample.
Variability-related constraints were set on: the index of the structure
function (Simonetti et al., 1985, structure_function_index in the table
vari_agn); quasar versus non-quasar metrics (Butler & Bloom, 2011,
qso_variability and non_qso_variability in table vari_agn); the Abbe (also
called von Neumann) parameter (abbe_mag_g_fov in table vari_summary) in the
$G$ band versus the renormalized unit weight error of the astrometric solution
(ruwe in table gaia_source). Additional cuts were made in the $G_{\rm
BP}\\!-\\!G$ versus $G\\!-\\!G_{\rm RP}$ colour space, on parallaxes and
proper motions, on the environment source number density (to avoid crowded sky
regions), on the scan angle correlation with photometric variation (to remove
artificial effects; see Holl et al., 2022), and finally on the variability
probability (to deal with clearly variable objects).

####  4.4.2 Galaxies

Figure 17: Light curves in the $G$ (black dots), $G_{\rm BP}$ (blue
triangles), and $G_{\rm RP}$ (red diamonds) bands of the known galaxy LEDA
2268723 (source_id 377643902971151872). Figure 18: Distributions (normalized
by area) of the field ipd_gof_harmonic_amplitude for sources of various
classes in the Gaia Andromeda Photometric Survey. ’Other’ includes constants
and those variable objects that were not targeted in Gaia DR3.

Figure 19: Statistics of light curves of objects in the Gaia Andromeda
Photometric Survey. Top: Standard deviation versus median $G$ magnitude.
Bottom: Normalized distribution of minimum-to-maximum variability range for
$G$ band light curves. Both panels are colour-coded as in Fig. 18. The
distributions overlap in the upper panel, with galaxies covering AGN, for
example.

About 2.5 million galaxies in the galaxy_candidates table were selected based
on the properties of their light curves. (Only a subset of these light curves
are published in Gaia DR3; see Sect. 2.5.) Gaia scans individual objects
multiple times at different position angles. For extended objects this can
produce an apparent -- but spurious -- photometric variability, because on
each scan only part of the total flux is collected by the limited size in the
allocated window (Holl et al., 2022). Figure 17 shows the light curve of a
known galaxy, in which we see variations in excess of 0.6 mag in $G$. Figure
18 shows the distribution (normalized by area) of the parameter
ipd_gof_harmonic_amplitude for galaxies, AGN, Gaia DR3 variable stars, and
other objects in the Gaia Andromeda Photometric Survey. This parameter
measures the amplitude of the variation of the Image Parameters Determination
goodness-of-fit statistic as function of the scan direction angle. Because
galaxies are often extended objects at the Gaia resolution, they tend to have
a larger value of this parameter than other types of objects. The galaxies
that are detected by variability are based on this type of spurious signal.
Figure 19 shows how the magnitude variability distribution of galaxies within
5.5∘ of the Andromeda Galaxy (M31) compares to that of other sources in the
same classes as in Fig. 18. We note that Gaia DR3 variable stars still amount
to a relatively small fraction of all variables detected in Gaia. The
brightness variations of galaxies overlap with high-amplitude tails of the
distributions of other classes.

##  5 Internal comparison

###  5.1 Classification

Table 4: Comparison of the classes of sources in the qso_candidates table according by its contributing modules. Each element gives the number of sources with different classifications between any two modules, expressed as a fraction of the number of sources in common between those two tables. Sources labelled unclassified in classlabel_dsc and classlabel_dsc_joint are excluded. The columns list all the modules that provide classifications. The rows list all modules that add sources to the table: the last four of these are not classifiers, but provide sources based on other labels.  QSO Other | DSC | DSC Joint | Variability | OA
---|---|---|---|---
classification | classification | classification | classification
DSC classification |  | 0.0 |  5.7 | 59.5
DSC Joint classification |  0.0 |  |  0.9 | 53.9
Variability classification |  9.5 | 0.5 |  | 44.6
OA classification | 30.2 | 1.1 |  7.1 |
Vari-AGN |  7.3 | 0.5 |  0.0 | 46.2
Surface brightness | 20.0 | 2.3 |  0.4 | 46.6
Gaia-CRF3 | 20.8 | 2.0 |  0.2 | 42.3
QSOC | 43.2 | 0.1 | 10.8 | 61.4
Table 5: As Table 4 but for the galaxy_candidates table.  Galaxy Other | DSC | DSC Joint | Variability | OA |  |
---|---|---|---|---|---|---
classification | classification | classification | classification |  |
DSC classification |  | 0.1 | 1.5 | 13.1 |  |
DSC Joint classification |  0.0 |  | 2.8 |  2.9 |  |
Variability classification | 37.6 | 0.0 |  |  0.7 |  |
OA classification | 59.7 | 6.4 | 1.3 |  |  |
UGC |  1.2 | 0.1 | 1.0 |  7.3 |  |
Surface brightness | 42.0 | 0.0 | 0.0 |  2.3 |  |

The various extragalactic modules (Sect. 2) use different methods and data.
This leads to a given source being classified differently in different
modules, which is apparent in the qso_candidates and galaxy_candidates tables
that collate results from all modules. On top of this comes the fact that
different modules use different definitions of quasar and galaxy, in
particular in the case of supervised learning algorithms, where the class is
defined by the training data set. Tables 4 and 5 show the percentage of
different classifications of the overlapping sources between modules based on
the class labels where they exist (DSC, DSC-Joint, OA, Vari-Classification) or
the existence of parameters (from UGC, QSOC, Vari-AGN, Surface brightness).
For example, classlabel_dsc and Variability give different classes for 9.5% of
their common sources. Such disagreements also come about because some modules
focus more on high completeness, whereas others focus more on high purity
(partially achieved by filtering). Recall also that the classification from a
module appears in the table even if that source would not have been selected
for inclusion in the table by that particular module (see Table 1). QSOC for
quasars and UGC for galaxies are subsets of DSC selected with the properties
described in Sections 2.2 and 2.3. Both use much lower thresholds on the DSC
probabilities than do the DSC class labels.

Gaia-CRF3 does not distinguish between galaxies and quasars. Most are expected
to be quasars so all are all in the qso_candidates table. OA works with a
small fraction of sources that are generally faint and noisy so the comparison
between OA and other modules should be carefully interpreted.

Figure 20: Comparison of DSC quasar classification probabilities (transformed
to normalized ranks) with scores from the variability analysis. Darker colours
depict higher densities, and the white line indicates the median rank. We see
a broad agreement between the highest and lowest ranked quasars.

DSC provides posterior class probabilities. vari_best_class_score (from Vari)
provides the median normalized rank, which also increases from 0 to 1 with
increasing reliability, but it is not a probability. To compare these
quantities, we map the DSC probabilities into normalized ranks. Figure 20
compares this for classprob_dsc_combmod_quasar to vari_best_class_score. The
deviation from a perfect correlation reflects the difference in input data
types, training sets and class definitions, and classification methods in
general.

###  5.2 Redshift

Figure 21: Comparison between the UGC and QSOC redshifts. Grey dots correspond
to all redshifts in common between the two tables, while black dots are
restricted to those with flags_qsoc = 0, which corresponds to a higher
reliability subset. The red curve denotes identical predictions in the two
modules. Yellow curves highlight mismatches between common quasar or AGN
emission lines, as explained in Delchambre et al. (2022), while the blue
vertical lines show constant predictions by QSOC.

Redshifts are derived by two modules, the results of which are reported in the
qso_candidates table (from QSOC) and the galaxy_candidates table (from UGC).
Of the 174 146 sources in common between the two tables, 16 534 have a
redshift derived by both modules. These are compared in Fig. 21. 7 469 of
these sources have predictions with $|\Delta z|<0.1$, and the correlation
improves when restricting the comparison to QSOC redshifts with higher
reliability (black dots in Fig. 21): In this subset, 105 of 166 sources have
$|\Delta z|<0.1$. Specific discrepancies arise from emission line mismatches
in the QSOC redshift determination. As QSOC aims to be complete, it processes
galaxies, even though UGC -- by design -- generally gets better predictions on
these objects (see Delchambre et al. 2022 for a more detailed explanation of
these emission line mismatches). UGC, in contrast, aims to be pure and is
accordingly not expected to process a significant number of quasars. Figure 21
shows loci of constant QSOC redshifts. These are probably erroneous matches at
the BP/RP spectral borders, where wiggles from the Hermite polynomials are
confused with quasar emission lines in the templates.

Figure 22: Colour-colour diagram for the 1 367 153 galaxies for which
redshifts are provided by UGC, colour-coded by redshift. A small number of
sources have redshifts extending up to 0.6

Figure 22 shows the colour--colour diagram for all sources for which UGC
provides a redshift value, colour-coded by redshift. We see that galaxies
generally become redder in $G_{\rm BP}\\!-\\!G$, but bluer in $G\\!-\\!G_{\rm
RP}$ as redshift increases from 0 to 0.4.

###  5.3 Sources with stellar parameters

The extragalactic tables contain sources for which stellar astrophysical