# A 95 GHz Class I Methanol Maser Survey Toward GLIMPSE Extended Green Objects
(EGOs)

Xi Chen11affiliation: Key Laboratory for Research in Galaxies and Cosmology,
Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai
200030, China<EMAIL_ADDRESS>2 2affiliationmark:  , Simon P.
Ellingsen33affiliation: School of Mathematics and Physics, University of
Tasmania, Hobart, Tasmania, Australia , Zhi-Qiang Shen11affiliation: Key
Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical
Observatory, Chinese Academy of Sciences, Shanghai 200030, China;
<EMAIL_ADDRESS>2 2affiliationmark:  , Anita Titmarsh 33affiliation: School
of Mathematics and Physics, University of Tasmania, Hobart, Tasmania,
Australia , and Cong-Gui Gan11affiliation: Key Laboratory for Research in
Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of
Sciences, Shanghai 200030, China<EMAIL_ADDRESS>2 2affiliationmark:

###### Abstract

We report the results of a systematic survey for 95 GHz class I methanol
masers towards a new sample of 192 massive young stellar object (MYSO)
candidates associated with ongoing outflows (known as extended green objects
or EGOs) identified from the _Spitzer_ GLIMPSE survey. The observations were
made with the Australia Telescope National Facility (ATNF) Mopra 22-m radio
telescope and resulted in the detection of 105 new 95 GHz class I methanol
masers. For 92 of the sources our observations provide the first
identification of a class I maser transition associated with these objects
(i.e. they are new class I methanol maser sources). Our survey proves that
there is indeed a high detection rate (55%) of class I methanol masers towards
EGOs. Comparison of the GLIMPSE point sources associated with EGOs with and
without class I methanol maser detections shows they have similar mid-IR
colors, with the majority meeting the color selection criteria
-0.6$<$[5.8]-[8.0]$<$1.4 and 0.5$<$[3.6]-[4.5]$<$4.0. Investigations of the
IRAC and MIPS 24 $\mu$m colors and the associated millimeter dust clump
properties (mass and density) of the EGOs for the sub-samples based on which
class of methanol masers they are associated with suggests that the stellar
mass range associated with class I methanol masers extends to lower masses
than for class II methanol masers, or alternatively class I methanol masers
may be associated with more than one evolutionary phase during the formation
of a high-mass star.

masers – stars:formation – ISM: molecules – radio lines: ISM – infrared: ISM

22affiliationtext: Key Laboratory of Radio Astronomy, Chinese Academy of
Sciences, China

##  1 Introduction

Methanol masers are quite common in massive star forming regions (MSFRs).
Historically they have been empirically classified into two categories (class
I and class II). The initial classification was based on the sources towards
which the different transitions were detected (Batrla et al. 1988; Menten
1991a). Class II methanol masers are often found to be associated with strong
centimeter continuum emission within 1′′ (e.g. ultracompact (UC) regions;
Walsh et al. 1998), infrared sources and OH masers. The strongest and best
known class II transition is the 5${}_{1}-6_{0}$ A+ line at 6.7 GHz. Since its
discovery (Menten 1991b), this class bright maser has become a reliable tool
for detecting and studying regions where massive stars form and are in their
very early stages of evolution (e.g. Minier et al 2003; Bourke et al 2005;
Ellingsen 2006; Xu et al 2008; Pandian et al 2008). A number of surveys have
been conducted for the 6.7 GHz class II methanol maser, resulting in the
detection of $\sim$ 900 sources in the Galaxy to date. The surveys include
those that are summarized in the compilation of Pestalozzi et al. (2005) and
the recent searches of Pandian et al. (2007), Ellingsen (2007), Xu et al.
(2008; 2009) and the Parkes Methanol Multibeam (MMB) blind survey ($\sim$ 300
sources (Green et al. 2009), but so far only part published by Caswell et al.
2010 and Green et al. 2010). In contrast class I methanol masers are usually
found offset by 0.1 - 1.0 pc from UC Hii regions, infrared sources and OH
masers (e.g. Plambeck & Menten 1990; Kurtz et al. 2004). A number of
observations of class I methanol masers showed that they were located at the
interface between molecular outflows and the parent cloud (Plambeck & Menten
1990; Johnston et al. 1997; Kurtz et al. 2004; Voronkov et al. 2006). These
early results suggested that class I and class II methanol masers favored very
different environments. These observational findings were supported by early
theoretical models of methanol masers which found that class I masers are
collisionally excited, in contrast to class II masers which have a radiative
pumping mechanism (Cragg et al. 1992). Observations made since the mid-1990s
(e.g. Slysh et al. 1994) have shown that at single dish resolutions class I
and class II masers are often associated. Observations at high spatial
resolution (e.g. Cyganowski et al. 2009) show that while the two types of
masers are typically not co-spatial on arcsecond scales, they are usually
driven by the same young stellar object.

Compared to class II masers, class I methanol masers are relatively poorly
studied and understood. There have only been a few large surveys for class I
masers (mainly at 44 and 95 GHz), primarily undertaken with single-dish
telescopes (e.g. Haschick et al. 1990; Slysh et al. 1994; Val’tts et al. 2000;
Ellingsen 2005) along with a few smaller scale interferometric searches (e.g.
Kurtz et al 2004; Cyganowski et al. 2009). These have resulted in the
detection of about 200 class I maser sources in the Galaxy to date (Val’tts et
al. 2010).

Observations and theoretical calculations suggest that class I methanol masers
can form in the interface region between outflows and the ambient molecular
gas. The methanol abundance is significantly increased in the shocked
interface regions (e.g. Gibb & Davis 1998) and the gas is heated and
compressed providing more frequent collisions, which results in more efficient
pumping (Voronkov et al. 2006). Interferometric observations have shown the
location of some class I methanol masers correlates closely with the shocked
gas in outflows as traced by 2.12 $\mu$m H2 and SiO (e.g. Plambeck & Menten
1990 ; Voronkov et al. 2006). However, such a close physical association
between the shocks driven by outflows and the class I masers has only been
firmly established in a small number of sources. One of the problems
encountered in studying the relationship between outflows (or shocks) and
class I methanol masers has been in finding an appropriate outflow tracer (one
which is frequently associated with class I maser emission). Recently
Cyganowski et al. (2008) have suggested that the 4.5 $\mu$m band of the
_Spitzer Space Telescope’s_ Infrared Array Camera (IRAC) offers a promising
new approach for identifying massive young stellar objects (MYSOs) with
outflows. The strong, extended emission in this band is usually thought to be
produced by shock-excited molecular H2 and CO in protostellar outflows (e.g.
Noriega-Crespo et al. 2004; Reach et al. 2006; Smith et al. 2006; Davis et al.
2007; Ybarra & Lada 2009, 2010). These extended 4.5 $\mu$m emission features
are commonly known as “extended green objects” (EGOs; Cyganowski et al. 2008)
or “green fuzzies” (Chambers et al. 2009) due to the common color-coding of
the 4.5 $\mu$m band as green in three-color images. These objects are
providing a new and powerful outflow tracer for MSFRs. Cyganowski et al.
(2008) have catalogued over 300 EGOs from the Galactic Legacy Infrared Mid-
Plane Survey Extraordinaire (GLIMPSE) I survey (Churchwell et al. 2009), and
they divided cataloged EGOs into “likely” and “possible” MYSO outflow
candidates based primarily on the angular extent and morphology of the 4.5
$\mu$m. Recent mid-infrared spectroscopic observations of two EGOs identified
by Cyganowski et al. showed the presence of strong shocked H2 in the 4-5
$\mu$m wavelength range from one of the sources, but no evidence for shocked
gas in the second (De Buizer & Vacca 2010). They suggest that some EGOs may be
due to spatial variations in the mid-infrared extinction and exaggerated color
stretches rather than shocked gas, however, the rate of mis-classification of
EGOs is at present very poorly determined. Based on the mid-IR colors of EGOs
and their correlation with infrared dark clouds (IRDC) and known 6.7 GHz
methanol masers, Cyganowski et al. (2008) further suggests that most EGOs
trace a population of actively accreting MYSO outflow candidates. Utilizing
the published high resolution masers known at the time, Cyganowski et al.
found that 6.7 GHz class II methanol masers are associated with 73% (35
detections from 48 EGOs) of “likely” and 27% (11 detections from 67 EGOs) of
“possible” MYSO outflow candidate EGOs.

Chen et al. (2009) have analyzed 61 EGOs from the Cyganowski et al. catalog
that have been included in class I methanol maser surveys. Four previous class
I methanol maser surveys (for the 44 GHz $7_{0}$–$6_{1}$ A+ transition by
Slysh et al. (1994) and Kurtz et al. (2004) and for the 95 GHz $8_{0}$–$7_{1}$
A+ transition by Val’tts et al. (2000) and Ellingsen (2005)) were included in
their statistical analysis. They found that 41 EGOs are associated with one or
both of the 95 and 44 GHz class I methanol masers within 1 arcmin, thus the
expected detection rate of class I masers in EGOs is 67% at this resolution.
Based on this high predicted detection rate, they suggested that GLIMPSE-
identified EGOs might provide one of the best targeted samples for searching
for class I methanol masers. However their statistical study is also subject
to unknown influences produced by the target selection effects in the four
class I maser surveys they have utilised in the study. For example, most of
the currently known class I masers are associated with class II masers (72% as
reported by Valt́ts & Larinov 2007), for which a good association with EGOs
has already been demonstrated by Cyganowski et al. (2008). Table 3 of Chen et
al. (2009) shows that most EGOs (57/61) used in their statistical analysis are
also associated with 6.7 GHz class II masers. According to Cyganowski et al.
(2008), the majority of EGOs (35/48=73% in the likely sample) are associated
with 6.7 GHz class II masers, and the sample of known class I masers is
largely a subset of the sample of known class II masers, so a high detection
rate for class I masers towards these EGOs is not unexpected. Recent 6.7 GHz
class II and 44 GHz class I methanol maser surveys toward $\sim$20 EGOs in the
northern hemisphere with the VLA reported by Cyganowski et al. (2009) also
show that $>$64% and 89% of EGOs are associated with class II and class I
methanol masers, respectively. However, their observations only targeted a
small number ($\sim$ 20) of “likely” outflow candidate EGOs. And their 44 GHz
survey sample is essentially a 6.7 GHz methanol maser selected sample (19
sources observed at 44 GHz (17/19 with class I masers), of which 18 had
associated 6.7 GHz methanol masers (16/18 with class I masers)).

In order to determine whether there is indeed a high association rate of class
I methanol masers in EGOs and to investigate the relationship between them, it
is necessary to perform a class I maser search towards a full EGO-based target
sample. In this paper, we report a 95 GHz class I methanol maser survey
towards an EGO-selected sample which has been undertaken with the Australia
Telescope National Facility (ATNF) 22-m millimetre antenna at Mopra. In
Section 2 we describe the sample and observations, in Section 3 we present the
results of the survey, the discussion is given in Section 4, followed by our
conclusions in Section 5.

##  2 Source selection and Observations

###  2.1 Source selection

The EGO catalog compiled by Cyganowski et al. (2008) lists a total of 302
sources, of which 137 are classified as “likely” and 165 as “possible” outflow
sources. All EGOs with declinations in the range from -62∘ to +25∘ are
accessible with Mopra. However, there are some sources which have an angular
separation of less than $\sim$20′′ (corresponding the half beam size of the
Mopra antenna; see below), from their nearest EGO. Where this occurred, we
observed at the position of those classified as “likely” outflow sources, or
when neither fell into this category, at the location with the larger 4.5
$\mu$m flux density. Chen et al. (2009) reported that 61 EGOs have previously
been observed in 44 and 95 GHz class I methanol maser surveys. For these
sources we re-observed 10 (of 16) EGOs which had not been observed at 95 GHz
in previous searches (see Table 1). Note that we did not make observations of
6 of the sources without 95 GHz information in Chen et al. sample in present
survey (see Table 6 for this). After applying these selection criteria we were
left with a total of 191 EGOs to be observed. Among these sources, 65, 17 and
3 sources were selected from Tables 1, 2 and 5 of Cyganowski et al. (2008),
respectively – thus 85 “likely” outflow candidates; 55 and 51 sources were
selected from Tables 3 and 4, respectively – thus 106 “possible” outflow
candidates. In addition, a well studied MYSO IRDC 18223-3 which shows
distinctly extended 4.5 $\mu$m emission (Beuther & Steinacker 2007) was also
included as a “likely” outflow candidate. In this paper we report the results
of our 95 GHz class I methanol maser survey toward these 192 sources.

Table 1 lists the target sample source parameters including the source name
(derived from the Galactic coordinates), the equatorial coordinates and
whether the EGO is associated with an IRDC, 6.7 GHz class II methanol maser,
1665 or 1667 MHz OH maser, UC Hii region or 1.1 millimeter (mm) continuum
source. The positional accuracies of the 6.7 GHz methanol maser catalogs
(Cyganowski et al. 2009; Caswell 2009; Xu et al. 2009; Caswell et al. 2010;
Green et al. 2010), OH maser catalog (Caswell 1998) and UC Hii region catalogs
(Wood & Churchwell 1989; Becker et al. 1994; Kurtz et al. 1994; Walsh et al.
1998; Cyganowski et al. 2009) used in our analysis, are usually better than
1′′. The positional uncertainty of the 1.1 mm continuum sources in the BOLOCAM
Galactic Plane Survey (BGPS) is also of the order of several arcseconds
(Rosolowsky et al. 2010). The Spitzer GLIMPSE point source catalog has also a
high positional accuracy (better than 1″), however, EGOs are extended objects
with angular extents between a few and $>$30′′ (Cyganowski et al. 2008). Thus
we have assumed an association between EGOs and other tracers for separations
of less than 30′′. For BGPS sources, we used their peak positions (rather than
centroid positions) available in the BGPS catalog (Rosolowsky et al. 2010) and
did not account for their sizes in the cross-matching. We list the
characteristics (including targeted/untargeted, area covered, angular
resolution, sensitivity and extent of overlap with the GLIMPSE I survey area
from which the EGO targets are drawn) for the maser, UC Hii region and BGPS
1.1 mm datasets used in our analysis in Table 2. To more clearly show the
associations among these tracers and EGOs, we have also ploted the positions
of the masers, UC Hii regions, and mm sources on the _Spitzer_ 3-color IRAC
images for all 192 targeted sources in our Mopra survey in Figure 1. From this
figure, it can be seen that most of class II methanol (marked by black
crosses) and OH masers (marked by red small circles) are close to the EGO
positions (marked by blue pluses) with typical separations between them of
less than 5$\arcsec$. But for UC Hii regions (marked by blue squares) and mm
sources (marked by yellow diamonds), they usually have a slightly larger
separation from the targeted EGO position. One possible reason is that the UC
Hii regions and mm sources have larger angular sizes, of order a few to a few
tens of arcseconds. Even though there are larger separations between EGOs and
UC Hii regions and mm sources, we still consider them to be associated in our
analysis. However we recognize that in some cases there may be no true
physical association between them.

###  2.2 Observations

The observations were made using the Mopra 22m telescope during 2009 August
9-20. Mopra is located near Coonabarabran, New South Wales, Australia. The
telescope is at latitude 31 degrees south and has an elevation of 850 metres
above the sea level. A 3 mm Monolithic Microwave Integrated Circuits (MMICs)
receiver with a frequency range from 76 to 117 GHz is installed. The UNSW
Mopra spectrometer (MOPS) provides four 2.2 GHz bands which overlap slightly
to give a total instantaneous bandwidth of 8 GHz. MOPS was used in zoom mode
for the observations reported here. In this mode, up to 4 zoom windows can be
selected within each 2.2 GHz band thus allowing up to 16 spectral lines to be
observed simultaneously at high spectral resolution. Each zoom window provides
a bandwidth of 137 MHz with 4096 channels for each polarisation, which leads
to a total velocity range of $\sim$ 430 km s-1 and a velocity resolution of
0.11 km s-1 per channel in the 3 mm band. The 8 GHz bandpass was centred at
94.3 GHz to provide a complete coverage over the 90.3–98.3 GHz range. Within
this range we configured the individual zoom windows to simultaneously cover
the strong lines in the 3 mm band, e.g. $1-0$ HNC (90.6635680 GHz),
$5_{k}-4_{k}$ CH3CN ($\sim$ 92 GHz), $1-0$ N2H+ ($\sim$ 93.17 GHz), $2-1$ CS
(97.9809533 GHz), $2-1$ C34S (96.4129495 GHz), $8_{0}-7_{1}$ A+ CH3OH maser
(95.1694630 GHz) and a series of lines of $2-1$ CH3OH ($\sim$ 96.7 GHz). In
this paper we will focus on the results of the 95 GHz class I methanol masers
band. The results from the other lines will be reported in subsequent
publications.

Each source was observed in a position-switching mode with 1 minute spent at
the on-source position and 1 minute at a reference position. This procedure
was repeated a number of times to yield a total of 11–13 minutes of on-source
integration for most sources. Two different reference positions offset by +8
and -8 arcminutes in declination from the targeted EGO sites were used. The
antenna pointing was checked at hourly intervals by observing nearby bright 86
GHz SiO masers with known positions. The nominal pointing accuracy is
estimated to be better than 5″. The system temperature was typically between
180-250 K depending on weather conditions and telescope elevation, resulting
in an rms noise level of $\sim$30 mK per channel after averaging the two
polarizations and Hanning smoothing. The half-power main-beam size and the
main-beam efficiency were 36′′ and 0.5, respectively at 3 mm band (Ladd et al.
2005). The measured antenna temperatures (T${}_{A}^{*}$) were further
calibrated on to a main beam temperature scale (TMB) by dividing by the main
beam efficiency. Then a conversion factor of 9.3 Jy K-1 can be estimated from
Equ. 8.19 of Rohlfs & Wilson (2004) to convert the main beam temperature to a
flux density. Thus a direct conversion factor from T${}_{A}^{*}$ to Jy would
be 18.6 Jy K-1. The resulting flux density detection limit was $\sim 1.6$ Jy
(3 $\sigma_{rms}$; the typical rms noise is $\sim$0.55 Jy) per channel. The
sensitivity of 18.6 Jy K-1 for our 95 GHz class I methanol maser survey is
significantly better than that of 40 Jy K-1 in previous similar surveys with
Mopra (e.g. Val’tts et al. 2000; Ellingsen 2005), largely because the
effective antenna diameter has been increased from 15 to 22 meters in the 3 mm
band since 1999.

The spectral line data were reduced and analyzed with the ATNF spectral line
reducing software (ASAP) and the GILDAS/CLASS package. During the reduction,
quotient spectra were formed for each on/off pair of observations which were
then averaged together. A low-order polynomial baseline fitting and
subtraction, and Hanning smooth were performed for the averaged spectra. For
some sources the resulting spectra still contained baseline ripples due to bad
weather and for these cases, we Fourier transformed the spectrum and flagged
the data in frequency space to reduce the influence of the baseline ripple.
This procedure was also undertaken with ASAP (for more details see the Mopra
Website111http://www.narrabri.atnf.csiro.au/mopra/obsinfo.html). Usually the
95 GHz methanol spectra do not have a particularly Gaussian profile, possibly
because the spectra are blended with multiple maser features within a similar
velocity range. We converted all the data into CLASS format and performed
Gaussian fitting of each possible maser feature for each detected source with
the CLASS package.

##  3 Results

###  3.1 Nature of Detected Emission

95 GHz class I methanol emission was detected towards 105 sites from the 192
searched positions, yielding a detection rate of 55% for this survey. The
detected sources are listed, along with the parameters of Gaussian fits to
their 95 GHz spectral features in Table 3. The detected emissions range in
strength from $\sim$ 0.2 to 108 Jy (corresponding to main beam temperatures
TBM $\sim$ 0.02 to 11.6 K), derived from the Gaussian fits. Spectra of each of
the detected 95 GHz emission after Hanning smooth are shown in Figure 2. The
sources for which no 95 GHz emission was detected are listed in Table 4, along
with the 1 $\sigma$ noise of the observation (typically less than 0.7 Jy). We
consider a source to have been detected if it exhibits emission stronger than
3 $\sigma$. All of the 105 detected 95 GHz methanol sources are new detections
in this transition. Among them, only 13 sources have previously been detected
in the 44 GHz class I methanol transition in recent VLA surveys (G34.26+0.15
detected by Kurtz et al. 2004; G10.29-0.13, G10.34-0.14, G11.92-0.61,
G18.67+0.03, G18.89-0.47, G19.01-0.03, G19.36-0.03, G22.04+0.22, G23.96-0.11,
G24.94+0.07, G25.27-0.43 and G39.10+0.49 detected by Cyganowski et al. 2009).
Therefore 92 new class I methanol emission sources have been found in this
survey. From the spectra of the class I methanol emission sources shown in
Figure 2 it can be seen that the class I emission often consists of one or
more narrow spectral features which can be treated as maser emission,
apparently superimposed on broader emission features. Examination of Table 3
shows that spectral features with widths $>$ 1 km s-1 are common in the
detected sources. The characteristic of broader emission features in class I
transition is very similar to that reported by Ellingsen (2005). From single-
dish observations we cannot determine whether these broad features are quasi-
maser/quasi-thermal emission, or due to blending of a number of weaker narrow
maser features (since the Mopra spectra almost certainly include multiple
class I maser spots blended within the beam, multiple weak masers at different
velocities could in aggregate produce some of the broad emission features
seen). However broad, quasi-thermal like spectral profiles are commonly
observed in class I methanol masers (see for example Kurtz et al. 2004, or
Voronkov et al. 2006). The majority of the broad emission in these sources
when observed interferometrically is observed to be maser emission. Thus,
although we cannot conclusively rule out the possibility that some of the
sources may have thermal emission contributions, comparison with previous
observations makes us very confident that the majority of the broad emission
is maser emission. Moreover some of the EGOs with previous 44 GHz maser
detections (Kurtz et al. 2004; Cyganowski et al. 2009) also show similar broad
emission profiles at 44 GHz (for Cyganowski et al. 2009, the 44 GHz maser
spectra were not directly presented, but they can be determined from the
fitted intensities of the 44 GHz emission listed in Table 8 of their work).
The similar broad emission features from class I methanol masers associated
with EGOs are also detected and spatially unresolved in 44 GHz VLA
observations (Kurtz et al. 2004; Cyganowski et al. 2009), which suggests that
they are generally masers. It has yet to be confirmed through interferometric
observations that the broad 95 GHz spectral features are also maser emission,
although given the results of numerous past interferometric observations of
class I masers this appears likely for the majority.

We also checked the flux densities of 44 GHz maser emission for the 13 EGOs
which were observed as 95 GHz masers in our Mopra survey, and found that the
peak flux densities of the 44 GHz masers are typically 2-3 times stronger than
that of 95 GHz masers, consistent with the statistical result from Val’tts et
al. (2000). However the primary beam of the VLA (1$\arcmin$ at 44 GHz) is
larger than that of Mopra (36$\arcsec$ at 95 GHz). Thus the detection of
stronger 44 GHz emission may be because for some sources with extended maser
emission the VLA can detect additional maser emission which is within the VLA
primary beam, but outside the Mopra beam (see Cyganowski et al. 2009). To
account for this potential affect, we compared only the 8 sources with all 44
GHz maser emission detected by the VLA locating in a compact region and within
Mopra beam. We found that the peak flux densities of 44 GHz emission are still
2-3 times stronger than that of 95 GHz emission for these sources.

In Table 3 we also list the distance and the integrated maser luminosity of
each of the 105 detected methanol maser sources. The distance was estimated
from the Galactic rotation curve of Reid et al. (2009), with the Galactic
constants, R⊙= 8.4 kpc and $\Theta_{\odot}$= 254 km s-1. Class I masers are
generally found near the VLSR as measured from the thermal gas (e.g.
Cyganowski et al. 2009). We adopted the velocity of the brightest feature in
the 95 GHz maser spectrum (listed in column 3 of Table 2) in the distance
calculation. The near kinematic distance was adopted for sources with a
near/far distance ambiguity. Given that EGOs are by definition extended
sources, there will be bias towards nearby sources in their identification and
also the nearby sources will be brighter and easier to detect. Another
argument for EGOs being more likely at the near kinematic distance is their
associations with IRDCs, because the identification of IRDCs is greatly biased
toward the near kinematic distance (see Jackson et al. 2008). Thus the near
distances adopted for these sources are likely to be more reasonable for most
sources. The distances to G49.07-0.33, G309.91+0.32, G310.15+0.76 which could
not be derived from the Galactic rotation curve were assumed to be 5 kpc.

###  3.2 Detection Rates

The results of our single-dish survey prove that there is indeed a high
detection rate ($\sim$55%) of class I methanol masers towards EGOs. It expands
the number of published class I methanol masers by about 50% (an additional 92
on top of the 198 listed by Val’tts et al. 2010). However given the large beam
size of Mopra and clustered massive star formation, a detection in a pointing
towards an EGO does not necessarily mean that the detected class I maser is
truly associated with the EGO, though recent VLA observations towards $\sim$20
EGOs reported by Cyganowski et al. (2009) revealed that nearly all 44 GHz
class I masers trace the diffuse green 4.5 $\mu$m features of EGOs except for
one case (G28.28-0.36). If this is true of the sample as a whole then it
suggests that the false association rate between EGOs and detected class I
masers is likely to be very low with a range of a few to (at most) 10%. Where
there were multiple EGOs included in the large beam of Mopra, we pointed at
the position of the EGO classified as a “likely” outflow source, or where
there were two such sources, at the position with the largest 4.5 $\mu$m flux
density (see Section 2.1). It is not clear which of the EGOs (all, or only
one) included in such observations are associated with the detected maser
emission. Thus it requires further high resolution observations toward the
detected class I masers to determine whether they are truly physical
associations with EGOs or which EGOs are associated with them. In subsequent
analysis, we have assumed that the detected maser emission is associated with
the EGOs used as the targeted point.

The detection rate of 55% achieved in this survey is slightly lower than the
predicted value of 67% from our previous statistical analysis (Chen et al.
2009). One possible reason for this is that our previous analysis combined 44
and 95 GHz class I maser searches, and emission from the 44 GHz transition is
generally 3 times stronger than that at 95 GHz (Val’tts et al. 2000). Thus it
may be possible to detect a significant number of additional sources if we
were to make a search with similar or better sensitivity at 44 GHz. To test
this conjecture, we checked all 20 EGOs with detected 44 GHz masers in
previous surveys (Kurtz 2004 and Cyganowski et al. 2009), and found that only
13 EGOs have detected 95 GHz emission at our Mopra survey sensitivity of
$\sim$2 Jy (i.e. the detection rate of 95 GHz methanol masers in these EGOs is
13/20$\sim$65%). All the remaining 7 EGOs detected at 44 GHz for which we did
not detect 95 GHz emission have peak flux densities of less than 6 Jy for the
44 GHz masers. This is consistent with our expectation that these 7 EGOs might
not be detected class I masers with the current detection limit (corresponding
to $\sim$ 6 Jy at 44 GHz when considering the 44/95 GHz correlation from
Val’tts et al. 2000). If we extrapolate this result to our survey it suggests
that we have detected around 2/3 of the true number of class I maser sources
in our search. If this were correct then our detection rate would be well in
excess of the prediction of Chen et al. (2009). This extrapolation naively
ignores the likely presence of selection biases in the VLA comparison sample
and the effect of the different primary beam of the VLA and Mopra as stated
above, but these are not readily assessed. The true rate of association of
class I methanol masers with EGOs can perhaps only be accurately determined
through targeted sensitive 44 GHz observations towards the non-detected
sources from this survey.

###  3.3 Associations with Class II Methanol Masers

Table 1 gives information on the association between EGOs and class II
methanol masers. For those sources in the Galactic longitude range covered by
sections of the MMB survey published to date (Caswell et al. 2010; Green et
al. 2010), or other similarly sensitive observations (Caswell 2009, Cyganowski
et al. 2009, Xu et al. 2009) we have used that data. For the remaining EGOs we
have made additional 6.7 GHz observations with the Mt Pleasant 26m telescope.
The Mt Pleasant observations will be described in detail in a separate
publication, but the basic characteristics are summarised here. At a frequency
of 6.7 GHz the Mt Pleasant 26m telescope has a 7$\arcmin$ beam FHWM and a
system equivalent flux density (SEFD) of around 800 Jy in each of two
orthogonal circular polarizations. The correlator was configured with 4 MHz
bandwidth and 4096 spectral channels for each circular polarization yielding a
velocity range for the observations of approximately 180 km s-1 and a velocity
resolution (after Hanning smoothing) of 0.09 km s-1. Observations were made
using 10 minute integrations towards each EGO target position observed at 95
GHz and the 3 $\sigma$ detection limit of the observations is around 1.5 Jy,
comparable to that achieved for the 95 GHz Mopra search. Although it is
possible that some of the EGOs not detected in the Mt Pleasant observations
may have a weak associated 6.7 GHz maser, this is likely to effect only a
small number of sources. From comparison with the MMB observations we estimate
this to be less than 10% of non-detections. While the class II methanol maser
data used in our comparison with the class I masers are not derived from a
homogeneous set of observations, their relative sensitivities differ only by
approximately a factor of 2 and are unlikely to introduce significant
additional uncertainty into our statistical analysis.

We have compared the cataloged EGOs with the subset of class II methanol
masers for which accurate positions have been published (see Section 2.1). Of
the 192 cataloged EGOs, 49 are found to be associated with class II masers and
81 were not. The results for the EGOs which are not associated with class II
masers were primarily determined from the surveys for 6.7 GHz methanol masers
with the Mt Pleasant 26m (see above). The remaining 62 EGOs were detected 6.7
GHz methanol masers by the Mt Pleasant 26m telescope, but lack a high-
precision position, thus we consider them as sources for which we have “no”
information with respect to the class II masers in our work. Among the 105
EGOs with detected class I methanol masers, we found that 39 EGOs are, and 31
EGOs are not associated with class II methanol masers, respectively. For the
other 35 EGOs we have insufficient information on the class II masers due to
the lack accurate position observations of the class II masers for these
sources. The sources associated with only class I methanol masers, but without
class II methanol masers are especially important for our understanding of the
properties of class I methanol masers, because most previous class I methanol
maser surveys were targeted towards known class II methanol masers. We have
undertaken further analysis and discussion of this issue in Section 4.2.

On the basis of one of the earliest class I methanol maser searches to detect
a large number of sources, Slysh et al. (1994) suggested that there exists an
anti-correlation between the flux densities of class I and class II methanol
masers towards the same sources. Ellingsen (2005) further investigated this
finding for a sample of class I methanol masers detected towards a
statistically complete sample of class II masers and in that case found no
evidence for an anticorrelation. We have also compared the peak flux densities
of class I and class II methanol masers in 39 sources associated with both
class masers. The peak flux densities of the class II masers are from
interferometric studies (Cyganowski et al. 2009; Caswell 2009; Xu et al. 2009;
Caswell et al. 2010; Green et al. 2010). The logarithms of the peak flux
densities of class I masers vs. that of class II masers are shown in Figure 3.
From this figure it can be seen that there is no statistically significant
correlation (or anticorrelation) between the flux densities of class I and
class II methanol masers in our observed EGO sample, consistent with the
result of Ellingsen (2005). The flux densities of the class II methanol masers
used in our comparison were all obtained from interferometric studies, whereas
the previous comparisons of Slysh et al. (1994) and Ellingsen (2005) used
single-dish data. However, the class II methanol maser emission is usually
distributed over a compact region typical $<$0.2′′ and are not resolved by
connected element interferometry (e.g. the VLA). This means that their flux
density is the same in interferometric and single dish studies and hence this
difference produces no new or additional biases to our statistical comparison.

###  3.4 Associations of Class I methanol masers with other star formation
tracers

In this section, we compare the detection rates of class I methanol masers in
different subsamples, including “likely” and “possible” outflow candidates,
IRDC and non-IRDC, those associated with class II methanol masers, OH masers,
and UC Hii region subsamples, etc. In order to more clearly compare the
various samples we have listed the information relating to the class I
methanol maser detections for all 192 sample sources in the last column of
Table 1. The detection rates for each of the different categories are
summarized in Table 5. It should be remembered that the detection rate in some
categories will be affected by the limitations of single dish surveys with a
large beam size and the clustering which occurs in high-mass star formation
regions (as described in Section 3.1).

A total of fifty three 95 GHz methanol masers were detected towards the 86
likely outflow sources targeted by our observations. The 53 detections include
40, 10 and 2 sources from Tables 1, 2 and 5 of Cyganowski et al. (2008),
respectively, and also IRDC 18223-3. This corresponds to a detection rate of
62% for the “likely” outflow sources. The remaining 52 class I masers
detections were made towards the 106 “possible” outflow candidate EGOs
observed. For the possible outflow sources, 27 and 25 were from Tables 3 and 4
of Cyganowski et al. (2008), respectively. This corresponds to a detection
rate of 49%. A z-test finds that the difference in these detection rates is
significant at the 90% level (i.e. it is marginally significant). Regardless
of this, it is apparent that the detection rate of class I methanol masers in
the “likely” outflow subsample is only slightly higher than that in the
“possible” outflow subsample. This suggests that the class I methanol maser
emission may be not very sensitive to the outflow classifications (i.e.
“likely” and “possible”) seen from the IRAC images. Alternatively, if we
assume that our finding for “likely” outflow sources is the true rate of
association between EGOs and class I methanol masers then this suggests that
approximately 49/62=79% of the “possible” outflow candidates are indeed
outflow sources.

Dividing our sample of EGOs searched for class I methanol masers on the basis
of their association (or otherwise) with IRDCs, we found that 71 of the 128
EGOs associated with an IRDC exhibit class I methanol maser emission (a
detection rate of 55%). Whereas, 34 of the 64 EGOs without an IRDC were
detected as class I methanol maser sources (a detection rate of 53%). IRDCs
are generally thought to host an early stage of the high-mass star formation
process, so it is somewhat surprising that our results show no difference
between the detection rate of class I methanol maser in those EGOs which are
and are not associated with an IRDC. The visibility of an IRDC is dependent on
both the strength of the mid-infrared background emission and the amount of
foreground emission, particularly at 8 $\mu$m (Cyganowski et al. 2008; Peretto
& Fuller 2009). If there is no, or weak 8 $\mu$m background emission in a
particular region, an IRDC may not be apparent even where dense molecular gas
and very young MYSOs are present. Moreover, MYSOs and YSOs of a range of
masses and evolutionary states are also found in IRDCs (e.g. Pillai et al.
2006; Ragan et al. 2009; Rathborne et al. 2010). So sources not associated
with IRDCs do not necessarily host a later evolutionary stage than those which
are.

Our target EGO sample included 49 sources associated with known class II
methanol masers for which the position is accurately known and 81 sources
which have been searched for class II methanol maser emission with no
detection by the Mt Pleasant 26 m telescope (see Table 1 and Section 3.2). We
found that 39 of the 49 sources associated with class II methanol masers were
detected in the 95 GHz class I methanol transition. Thus there is a very high
detection rate ($\sim$ 80%) of class I methanol masers towards EGOs which are
also associated with class II methanol masers, which is somewhat lower than
the 89% reported by Cyganowski et al 2009, but likely not significant given
the sensitivity differences between the observations. In comparison only 31 of
the 81 sources not associated with a class II methanol maser were found to
have an associated 95 GHz class I methanol maser (a detection rate of 38%). A
more in-depth discussion about the lower detection rate of class I methanol
masers towards those EGOs without an associated class II methanol maser and
the evolutionary relationship between class I and class II methanol masers is
given in Section 4.2.

Comparing the positions of the EGOs we observed with the spatial region of the
Parkes/ATCA 1665/1667 MHz OH maser survey (see Table 2) (Caswell 1998), we
found that there were 104 targeted EGO sources within the survey area of the
Parkes OH maser survey. Amongst these, 14 EGOs were, and 90 EGOs were not
associated an OH masers. Nearly all (13 of 14) of the EGOs associated with an
OH maser, while approximately one-half (43 of 90) of the sources not
associated with an OH maser were found to have a class I methanol maser.

We also note that there is a very high detection rate (11/13=85%) of class I
methanol masers towards those EGOs which are associated with an UC Hii region.
For most EGOs no deep centimeter continuum data is available. There are two
Hii region survey datasets that we have used to compile a category of “without
associated UC Hii region” for comparison. The survey of Becker et al. (1994)
covered the region of $|b|<0.4^{\circ}$ and $l=350^{\circ}-40^{\circ}$ (see
Table 2). The other observations are those by Cyganowski et al. (2009) towards
$\sim$20 EGOs in the northern hemisphere, who found that no 44 GHz continuum
emission was detected toward 95% of their surveyed EGO sample. Using the
published data from these two sets of observations, we compiled a sample of 34
EGOs that are not associated with an UC Hii region. From this sample, 21
sources were found to have an associated class I maser. Thus the detection
rate of class I masers of 21/34=62% towards EGOs without associated UC Hii
regions is lower than that in sources which are associated with UC Hii
regions. The size of the subsample associated with UC Hii regions used in our
statistical analysis is small, and they may be biased since many of the large-
scale UC Hii region surveys cited were targeted based on IRAS colors. In
addition, high-mass star formation usually occurs in a cluster environment, so
for an EGO associated with an UC HII region, it is not clear a priori whether
the 4.5 $\mu$m outflow is driven by the UC Hii region or by another
(potentially lower-mass or less evolved) source in a (proto)cluster. However,
given that UC ii regions are relatively rare towards EGOs, the high detection
rate of class I methanol masers in those few sources where they have been
observed to date is suggestive.

There are 63 EGOs which fall within the 1.1 mm BGPS survey area (Rosolowsky et
al. 2010). Fifty four of these are associated with BGPS sources within 30′′,
and 9 are not (see Table 2). We find that the detection rate of class I maser
in the EGOs with an associated BGPS source (35/54=65%) is higher than that in
those without an associated BGPS source (1/9=11%; only one EGO G34.39+0.22 in
this category was detected to have class I maser emission). Conversely, all
class I maser sources except G34.39+0.22 which fall within the BGPS survey
region have an associated 1.1 mm BGPS source.

##  4 Discussion

###  4.1 The mid-IR colors of the class I methanol masers

Based on their mid-IR colors ([3.6]-[5.8] versus [8.0]-[24]), Cyganowski et
al. (2008) have suggested that most EGOs fall in the region of color-color
space occupied by the youngest MYSOs and are surrounded by substantial
accreting envelopes (see Figure 13 in their work). We have performed
additional color-color analysis for EGOs to further investigate the
distinguishing mid-IR properties of EGOs with and without an associated class
I methanol masers. Our mid-IR color analysis includes the 192 EGOs targeted
for our class I maser observations and an additional 51 EGOs that are listed
in our previous work (Chen et al. 2009), but were not observed in our Mopra
survey. We list the information (including their associations with class I
masers and high-precision position class II masers) of these 51 EGOs in Table
6. There are 6 EGOs without 95 GHz class I maser information listed in this
table since they were omitted in our Mopra survey (see also Section 2.1).
Adopting the integrated mid-IR flux densities in the four IRAC bands presented
in Tables 1 and 3 of Cyganowski et al. (2008), we have plotted a diagram of
the [3.6]-[4.5] versus [5.8]-[8.0] colors of these selected EGOs in Figure 4
(note that we do not consider the flux density limitation on each IRAC band
denoted by column 12 of Tables 1 and 3 of Cyganowski et al. in our analysis).
In total, 81 and 58 EGOs with and without an associated class I methanol maser
(see Tables 1 and 6) are shown in this figure represented by red and blue
triangles, respectively. The regions of color-color space for sources at
different evolutionary Stages I, II and III, derived from the 2D radiative
transfer model by Robitaille et al. (2006) are also marked in Figure 4. We
found that most EGOs fall in the region occupied by the youngest protostar
models (Stage I), consistent with the conclusions from Cyganowski et al.
(2008). There is significant overlap in colors between sources with and
without class I methanol masers. Figure 4 also shows that many EGOs lie in the
upper-left of the color-color diagram, and outside the Stage I evolutionary
zone. One possible reason for this is that the colors of these sources are
effected by reddening. The reddening vector for Av$=$20 derived from the
Indebetouw et al. (2005) extinction law is shown in Figure 4\. An
A${}_{v}\sim$80 can produce reddening of approximately 1.4 mag in the
[3.6]-[4.5] color, which would be sufficient to return most of these source to
the Stage I region. However, such a large extinction value Av$\sim$80 is of
dubious plausibility, since the path to the Galactic center has a total
Av$\sim$25 (Indebetouw et al. 2005). Another possibility is that because the
mid-IR flux density measurements were determined from an extended region (i.e.
extended green region), with a typical scale of a few to 30′′, they may
include emission from many GLIMPSE point sources which are not physically
associated with the EGO, shifting the colors for some sources outside the
Stage I region. Moreover the integrated fluxes likely include emission
mechanisms (H2 and PAH line emission in particular) which were not included in
the Robitaille et al. models. This also may result in some sources with
extended 4.5 $\mu$m and PAH emission lying outside the Stage I region.

We have also undertaken additional similar color-color analysis using flux
measurements for all EGOs extract from the highly reliable GLIMPSE point
source catalog (rather than the less reliable GLIMPSE point source archive).
This analysis may allow us to determine whether it is possible to refine the
criteria for targeting class I methanol masers using mid-IR colors of GLIMPSE
point sources, similar to the analysis undertaken by Ellingsen (2006) for
class II methanol masers. The sample includes the 192 EGOs in the current
Mopra observations and an additional 51 EGOs listed in our previous work (Chen
et al. 2009). Although EGOs are by definition extended objects, the GLIMPSE
point catalog allows us to study the characteristics of the possible driving
source of the EGOs and class I methanol masers. To decrease the contamination
of our investigation of the EGO driving sources from chance associations, we
assumed that the driving source is the closest point source to the cataloged
EGO position (within 5$\arcsec$), with flux measurements in all four IRAC
bands. Using these criteria we identified the assumed driving GLIMPSE point
sources for 126 EGOs (including 74 associated with detected class I methanol
masers and 52 without class I methanol masers; see Tables 1 and 6). In Figure
5 we have marked these closest associated GLIMPSE point sources using red and
blue triangles for EGOs which are and are not with associated class I methanol
masers respectively. Examination of Figure 5 clearly shows that the GLIMPSE
point sources which lie closest to the EGOs are predominantly inside the
color-color region representative of Robitaille et al. evolutionary Stage I.
Qualitatively Figures 4 and 5 show similar color-color distributions, except
perhaps for a greater spread in the [3.6]-[4.5] color for the point source
data compared to the integrated fluxes. We have used the sample of 126 GLIMPSE
point sources identified in the manner outlined above to perform our
subsequent color-color analysis for EGOs with/without class I methanol masers.
It is almost certain that there are some false associations between the
GLIMPSE point sources assumed to be the driving sources and the true driving
sources of the EGOs. For example, in some cases the true driving sources for
EGOs may not appear in the GLIMPSE point source catalog, either due to
saturation, the presence of bright diffuse emission (which limits point source
extraction), or inherently extended morphology in the IRAC bands with the IRAC
resolution, e.g. due to extended PAH emission or extended H2 emission from
outflows (see Robitaille et al. 2008, Povich et al. 2009, and Povich & Whitney
2010). Moreover the EGO position cataloged by Cyganowski et al. (2008) adopted
the position of the brightest 4.5 $\mu$m emission within the extended region
of the EGO, but it is not clear that the brightest 4.5 $\mu$m emission
associated with an EGO must necessarily lie close to the driving source.
However, given the extended nature of EGOs such identifications will always be
somewhat problematic. The presence of false associations will add confusion to
attempts to identify any color-color differences between EGOs with and without
class I methanol masers; however, provided the mis-identification rate is not
too large (it is not possible to make a quantitative estimate for this at
present) it is unlikely to mask the difference completely, if it is present.

We find that the color-color regions occupied by GLIMPSE point sources which
are and are not associated with class I methanol masers are not significantly
different. For both groups they predominantly lie in a box region
-0.6$<$[5.8]-[8.0]$<$1.4 and 0.5$<$[3.6]-[4.5]$<$4.0. This color-color region
is very similar to that occupied by 6.7 GHz class II methanol masers
identified by Ellingsen (2006). But interestingly, we note that the class I
methanol masers extend to smaller [3.6]-[4.5] colors than do the class II
methanol masers for which the [3.6]-[4.5] color is usually greater than 1.3.

Similar to what is seen in Figure 4, Figure 5 shows that many GLIMPSE point
sources which are closest to an EGO lie in the upper-left of the color-color
diagram, and outside the Stage I evolutionary zone derived from 2D radiative
transfer models (Robitaille et al. 2006). Some of the GLIMPSE point sources
have redder [3.6]-[4.5] colors ($>$3), compared to those seen in Figure 4
which typically have [3.6]-[4.5] $<$ 3\. As discussed above, these sources may
be those which suffer larger reddening, however it requires extreme extinction
(A${}_{v}>100$) to produce such large color shifts ($>$2) in [3.6]-[4.5]. The
typical Av of an IRDC simply estimated from the parameters provide by Peretto
& Fuller (2009) is 25 (here we adopted an average optical depth at 8 $\mu$m of
1.15 for IRDCs, and A8μm/Av=0.045 from that work). Since most EGOs are
associated with IRDCs (Cyganowski et al. 2008), this shows that typical Av for
IRDCs can not account for the entirety of redder colors of these sources. From
our calculations of Av for the 1.1 mm BGPS sources associated with EGOs which
have class I maser detections (see Table 7, with more details described in
Section 4.3), the estimated Av of the 1.1 mm clumps associated with EGOs
outside stage I region ranges from 10 to 40 (with an average of 20), similar
to that for sources inside the Stage I region which range from 5 to 50 (with
an average of 23). This also suggests that the reddening does not play an
important role in explaining the redder colors of these sources. Another
possible reason for this is that the GLIMPSE point source photometry (similar
to the integrated flux measurements discussed above) may be affected by
contributions from extended H2 emission, while the classifications of Stage
I-III by Robitaille et al. (2006) did not consider these emission mechanisms.
The EGOs associated with GLIMPSE point sources outside Stage I region have a
significantly higher detection rate for class I methanol masers (21/28=75%;
see Tables 1 and 6) than that observed in the full sample (55%). We have also
checked the masses of 1.1 mm BGPS sources associated with EGOs which have
class I methanol maser detections (see Table 7, and the additional details
described in Section 4.3), and found that the mass range of the BGPS sources
associated EGOs outside stage I region (covering the range 1000-6000 M⊙ with
an average of 2500 M⊙) is significant higher than those associated with EGOs
in Stage I region (73-2000 M⊙, with an average of 1200 M⊙). Thus they may
correspond to MYSOs with an extremely high mass envelope which is more deeply
embedded causing redder colors. Moreover, the detection rate of class I
methanol maser in EGOs tends to be higher (30/40=75%) in the color-color
region with [3.6]-[4.5] $>$ 2.4. Given that EGOs are identified and defined by
their excess 4.5 $\mu$m emission, the high detection rate of class I masers
towards EGOs that fall in the left-upper regions make sense if the excess 4.5
$\mu$m emission is due to shocked H2 in outflows, and so sources in the left-
upper region may have particularly strong/active outflows which can readily
produce maser emission. This suggests that GLIMPSE point sources with redder
[3.6]-[4.5] color are the best target population for class I methanol maser
searches. However, the small number ($\sim$30) of class I methanol maser and
small number ($\sim$40) of GLIMPSE point sources in this region of color space
should be taken into account when drawing any conclusions.

###  4.2 An evolutionary sequence for class I and II masers

Ellingsen et al. (2007) suggested that the common maser species (class I and
II methanol, water, and OH masers) may help identify the evolutionary phase of
a high-mass star, and proposed a possible evolutionary sequence for these
common maser species. This proposed sequence has recently been refined and
quantified by Breen et al. (2010a) in their Figure 6. However, there remains
significant uncertainty about where within star formation regions the
different maser species arise and the evolutionary phase they are associated
with. In this work, we focus on the evolutionary sequence for class I and II
methanol masers. In previous work, one of the main difficulties in determining
the relative evolutionary sequence for class I and II masers has been the lack
of a large sample of sources associated with class I masers but not class II
masers. Ellingsen (2006) investigated the mid-IR colors of the associated
GLIMPSE point sources for a relatively small sample of class II methanol
masers associated with and without class I methanol masers numbering $\sim$10
for each group, and found there is a tendency for the sources with an
associated class I methanol maser to have redder GLIMPSE colors than those
without class I methanol masers. Based on the assumption that the redder
colors are associated with more deeply embedded and hence youngest stellar
objects, Ellingsen (2006) suggested that some class I methanol masers may
precede the earliest class II methanol maser evolutionary stage. However, the
absence of a comparison sample of class I methanol masers with no associated
class II methanol masers presents a significant limitation to the Ellingsen
(2006) work. Our class I methanol maser survey towards EGOs has identified 31
sources which are associated with class I, but not class II, methanol masers.

To test the proposed evolutionary scenario for class I and II methanol masers,
the EGOs were split into three subsamples on the basis of which class methanol
masers they were associated with (see Tables 1 and 6): 1) associated only with
class I methanol masers (32 members in total; 31 from our surveyed sample and
1 from Chen et al. 2009 sample); 2) associated only with class II methanol
masers (20 members in total; 10 from our surveyed sample and 10 from Chen et
al. 2009); 3) associated with both class I and class II methanol masers (72
members in total; 39 from our surveyed sample and 32 from Chen et al. 2009).
In compiling the second and third subsamples we only considered sources for
which the position of the class II maser emission is known to high accuracy
(i.e. the sources with class II methanol maser information marked by “Y” in
Tables 1 and 6). IRAC and Multiband Imaging Photometer for Spitzer (MIPS) 24
$\mu$m colors provide a diagnosis for YSO evolutionary state (Robitaille et
al. 2006). We plot [3.6]-[5.8] versus [8.0]-[24] color diagram using the flux
measurements from Tables 1 and 3 of Cyganowski et al. (2008) for the above
three subsamples (note that we do not consider the flux density limitations on
the IRAC and MIPS bands in this plot) in Figure 6 with different symbols. The
regions of color-color space for sources at different evolutionary stages I,
II and III derived from Robitaille et al. (2006) are also marked in Figure 6.
In total, we have 26 EGOs containing both class I and II methanol masers, 7
EGOs associated with only class II methanol masers and 25 EGOs associated with
only class I methanol masers in this figure. Comparing the color distributions
of these three subsamples with the color-color space occupied by the
evolutionary stages derived from Robitaille et al. (2006), we find that all
class II maser EGOs (including both class I and II maser subsample and the
only class II maser subsample) are located in the region of Stage I, i.e. the
easiest evolutionary stage, while all but one class I maser only EGOs are also
located in the Stage I region (the exception is G317.88-0.25 which lies in
Stage II). However, as seen in Figure 6, despite the significant overlap of
the various subsamples, EGOs which are associated with only class I methanol
masers extend to less red colors than those associated with only class II
methanol masers and both class I and II methanol masers.

Here we propose a number of possible explanations as to why the mid-IR sources
associated with only class I methanol masers have less red colors than those
associated with class II methanol masers:

1\. The EGOs associated with only class I maser are less heavily extincted
than those associated with class II masers.

2\. The stellar mass range of objects with associated class I methanol masers
extends to lower masses than that of objects with class II methanol masers.
The lower mass sources may be generally less deeply embedded and hence have a
less red colors, than the higher mass objects.

3\. There may be two epochs of class I methanol maser emission associated with
high-mass star formation. An early epoch which overlaps significantly with the
class II methanol maser phase and a second phase which occurs after class II
methanol maser emission has ceased.

The first possibility is supported by the evidence that the mid-IR color
differences among the three subsamples shown in Figure 6 are mostly along the
direction of the reddening vector. But it needs a very large Av to produce the
color shifts observed between the EGOs associated with only class I masers and
those associated with class II masers (e.g. A${}_{v}\sim$80 corresponds to a
color shift of 3 in [8.0]-[24]). Even though at present we can not accurately
determine Av for our full sample sources, as discussed in Secion 4.1 from
estimations of Av for a few sources associated with 1.1 mm BGPS listed in
Table 7 and the typical Av for IRDCs which are often associated with EGOs, it
appears that reddening alone is unlikely to be responsible for the observed
color differences among the three subsamples.

The second possibility is also consistent with other recent observations of
class I methanol masers. Class I methanol masers are known to be associated
with some regions that are forming only low-mass stars (Kalenskii et al. 2006,
2010). This suggests that class I methanol masers can be associated with lower
stellar mass sources than class II methanol masers and hence supports this
possibility. To further test this we have compared the detected 95 GHz class I
maser luminosity distributions of four subsamples. The subsamples of class I
masers are (a) those not associated with class II masers; (b) those associated
with class II masers for which an accurate position has been measured; (c)
those associated with an UC Hii and (d) those associated with an OH maser. The
distribution of the 95 GHz class I maser luminosity for each of these
subsamples is shown in Figure 7. This shows that most (25/31$\approx$80%) of
the sources which are not associated with class II methanol masers are located
in the lowest luminosity bin (less than 5$\times$10-6 L⊙); whereas those
associated with class II masers, UC Hii regions and OH masers have a
relatively small fraction (typically 40%) in this lowest luminosity bin. One
explanation for the observed distributions is that class I masers can be
associated with lower stellar mass sources than class II masers or the other
two tracers (OH and UC Hii), since class I maser excited by outflows from low
stars are expected to be less luminous. Recalling Section 3.3, the detection
rate of class I methanol masers in the sources without an associated class II
maser (37%) is lower than that in the sources with an associated class II
maser (80%). This statistical result also seems to support the hypothesis that
class I methanol masers can extend lower stellar mass sources since less
luminous class I masers excited from lower mass stars are harder to detect
with the same sensitivity. This hypothesis is also supported by our further
analysis of the relationship between class I methanol masers and 1.1 mm BGPS
sources (discussed in Section 4.3).

The last hypothesis is more speculative, as it requires the mechanism through
which class I methanol masers are produced to be switched off and then at a
later time on again. It is generally considered that sources with associated
OH masers and UCHii regions lie towards the later evolutionary phases (Breen
et al. 2010a). The very high rate of association we have found for class I
methanol masers towards OH masers (93%; see Table 5) demonstrates that some
class I methanol masers may be present at these later stages. However the
current single dish survey with large beam size is not sufficient to argue
that the driving source of OH maser is also responsible for exciting the class
I maser emission. Further high-resolution observations are needed to
definitively establish whether the class I masers are truly associated with
the same MYSO as the OH masers, although the results of Cyganowski et al.
(2009) suggests that most of the detected class I masers will be associated
with the targeted EGOs. Recently Voronkov et al. (2010) presented new high
resolution observations which strengthen the case that some class I methanol
masers are produced in shocks driven into molecular clouds from expanding Hii
regions. The 9.9 GHz class I methanol masers (detected towards 4 of 48 class I
maser sources observed by Voronkov et al.), are all associated with relatively
old sources, e.g. Hii regions and OH masers. They also tentatively report a
detection rate of greater than 50% for 44 GHz class I methanol masers towards
OH masers which are not associated with class II methanol masers. This
indicates that the class I masers can extend beyond the time when class II
masers are destroyed, and overlap well into the time when OH masers are
active. Voronkov et al. suggest that these findings are consistent with the
cloud-cloud collision hypothesis for class I methanol masers which has been
realized in some sources (Sobolev 1992; Mehringer & Menten 1996; Salii,
Sobolev & Kalinina 2002), but are in contrast with the generally held view of
class I methanol masers derived from sources such as DR 21(OH) (Plambeck &
Menten 1990) and G343.12-0.06 (Voronkov et al. 2006) where they are clearly
associated with outflow-molecular cloud interaction regions.

Our findings and those reported by Voronkov et al. (2010) are inconsistent
with some aspects of the evolutionary sequence presented by Breen et al.
(2010a) which has both the appearance and disappearance of class I methanol
masers preceding that of the class II methanol masers. Breen et al. also have
no overlap between the class I methanol masers and OH maser stages. In our
survey the EGOs which are associated with class I methanol masers, but not
class II methanol masers are not found to be associated with any known
published Hii regions or OH masers (actually there is absence of any systemic
surveys of Hii regions or OH masers towards EGOs at present). This suggests
that these class I methanol masers are likely to be excited by shocks driven
from outflows, rather than in the shocks driven by expanding Hii regions at
later evolutionary stage. However, the true nature of these class I only EGOs
can only definitively be resolved by high resolution observations which can
determine the location of the maser emission with respect to the EGOs. Because
high-mass star formation regions are crowded and frequently contain objects at
a range of evolutionary phases, chance associations are possible at low
angular resolutions. Examination of the results of Cyganowski et al. (2009)
for the source G28.28-0.36 illustrates how this can occur. For the majority of
the EGOs imaged by Cyganowski et al. (2009) in the 6.7 GHz class II and 44 GHz
class I methanol maser transitions, both types of masers are clearly
associated with the targeted EGOs. However, in the case of G28.28-0.36, while
the 6.7 GHz class II methanol masers are associated with the EGO, the class I
masers are offset and clearly trace the interface between an Hii region and
the surrounding molecular gas. With single dish spatial resolution both maser
transitions and the EGO would be considered likely to be coincident, although
with the benefit of high resolution data this is clearly not the case. This is
only one object from $\sim$20 observed by Cyganowski et al., so it is not
likely that all of the class I only EGO sources we have identified are chance
detections unrelated to the EGO, however, it is possible that some may be.

The evolutionary scheme outlined by Ellingsen et al. (2007) and Breen et al.
(2010a) assume that each maser species arises only once during the evolution
of an individual massive star. However, it appears that this assumption may
require revision for class I methanol masers. One possible manifestation of a
two evolutionary phase scenario for class I methanol masers (as discussed
above) would be that they initially arise at a relatively early phase of the
star formation process when powerful outflows interact with surrounding
molecular gas and that they are typically accompanied by class II maser
emission during this phase (the birthplace (disk or outflow) of class II
methanol masers remains uncertain, but at least in some sources 6.7 GHz class
II methanol masers can be excited in the inner regions of outflows e.g. De
Buizer 2003). As the source evolves and the outflows diminish the class I
maser emission fades and ceases, but the class II maser emission continues,
before it too fades rapidly soon after the creation of the UC Hii region. As
the ionized bubble rapidly expands it creates a second phase of class I maser
emission at the interface with the ambient molecular gas. Of course, there is
the possibility that the lifetime of class I masers associated with outflows
may also continue as far as the stage when Hii regions are detectable.
Molecular line observations of several massive star-forming regions show
evidence that outflows (and infall) can continue once ionization turns on, and
an UC Hii region is formed (e.g. Keto & Klaassen 2008, Chen et al. 2010).
However, high-mass star formation occurs in a cluster environment which may
include sequential or triggered star formation, allowing a YSO associated with
a well developed Hii region and a YSO associated with young outflow may
coexist as near neighbours. The extended spatial distribution of class I
masers compared to the other common maser species makes it more difficult to
determine which object the emission is associated with, outflow or expanding
Hii region or both astrophysical phenomena (particularly without high-
resolution data). At present we cannot determine whether the class I methanol
masers associated with outflows survive through to the stage when Hii region
appear, although it appears possible from our results that this is the case.

At present we cannot confidently determine why the MIR colors of class I only
sources extends to less red colors than those associated with class II masers.
It seems unlikely to be purely the result of less reddening in these sources,
but both association with lower mass stars and their being more than one epoch
of class I maser emission remain plausible hypotheses. Further observations an
millimetre and submillimetre wavelengths, combined with high resolution
observations of the class I masers will be required to answer this question.

###  4.3 The properties of mm dust clumps associated with methanol masers

Table 1 shows that there are 63 EGOs in our observations which are within the
1.1 mm continuum BGPS surveyed area (Rosolowsky et al. 2010). Among them, 54
are associated with a 1.1 mm BGPS sources, while 9 are not (see also Table 2).
A 1.1 mm BGPS source was considered to be associated with an EGO if the
separation between the peak position of the BGPS source and the EGO position
is less than 30′′. We did not take the size of the mm continuum source into
account when cross-matching (see Section 2.1).

In the two-evolutionary phase hypothesis for class I methanol masers discussed
in Section 4.2, we might expect similar trends to that seen in the Mid-IR
colors (e.g. Figure 6) to be present in other physical tracers of the source
evolution, such as the density of the associated gas and dust. For example,
Breen et al. (2010a; 2010b) suggest that the density of the associated dust
and gas decreases as the sources evolve for class II methanol masers and water
masers. So in the two-evolutionary phase hypothesis we would predict class I
methanol only sources should have a lower gas density than class II methanol
maser only sources, which in turn would have a lower density than those
sources with both class I and II methanol masers. To test this, we perform an
investigation of the properties of 1.1 mm BGPS dust clumps associated with
class I methanol masers in our surveyed sample and Chen et al. (2009) sample
(37 sources in total). For each of the associated 1.1 mm BGPS source, we have
assumed that the 1.1 mm emission detected toward EGOs is from optically thin
dust. We can then calculate the gas mass using the equation:

$M_{gas}=\frac{S_{\nu}(int)D^{2}}{\kappa_{d}B_{\nu}(T_{dust})R_{d}},$ (1)

where $S_{\nu}$(int) is the 1.1 mm continuum integrated flux density, $D$ is
the distance to the source, $\kappa_{d}$ is the mass absorption coefficient
per unit mass of dust, $B_{\nu}(T_{dust})$ is the Planck function for a
blackbody at temperature $T_{dust}$, and $R_{d}$ is the dust-to-gas mass
ratio. Here we adopt $\kappa_{d}$$=$1 cm2 g-1 (Ossenkopf & Henning 1994) for
1.1 mm emission, and assume a dust-to-gas ratio ($R_{d}$) of 1:100.
$B_{\nu}(T_{dust})$ was derived for an assumed dust temperature of 20 K. The
H2 column and volume densities of each dust clump were then derived from its
mass and radius (Robj), assuming a spherical geometry and a mean mass per
particle of $\mu=2.29$ mH, which takes into account a 10% contribution from
helium (Faúndez et al. 2004). We list the parameters of the 1.1 mm continuum
integrated flux density, $S_{\nu}$(int) and 1.1 mm source radius, Robj
obtained from the BGPS catalog (Rosolowsky et al. 2010) for all the 37 class I
maser sources with an associated 1.1 mm BGPS source in Table 7. Dunham et al.
(2010) suggested that a correction factor of 1.5 must be applied to the
Rosolowsky et al. BGPS catalog flux densities. In this paper, we also apply
this flux calibration correction factor to the integrated flux density
$S_{\nu}$(int) listed in Table 7. All the associated 1.1 mm BGPS sources are
resolved with the BGPS beam, with the exception of G34.28+0.18. For this
source we assumed half the beam size (17′′) as an upper limit for the object
radius. Thus the derived gas density of this source should be seen as a lower
limit. The masses and gas densities for all 1.1 mm dust clumps associated with
class I methanol masers determined using the methods outlined above are listed
in Table 7.

Figure 8 presents a log-log plot of the luminosity of the class I methanol
maser emission versus of the gas mass (left panel) and H2 density (right
panel) of the associated 1.1 mm dust clump. We have used different symbols in
the plot to show whether the class I masers are associated with class II
methanol masers or not (21 with associated high-precision position class II
masers; 9 without high-precision position class II maser data; 7 without
associated class II masers; see Table 7). Figure 8 shows that a weak, but
statistically significant positive correlation exists in both cases. We have
performed a linear regression analysis for each distribution, and plotted the
relevant line of best fit in each panel in Figure 8. The best fit linear
equation for each distribution is as follows:

log(Lm/Lsun)$=$0.50[0.14]log(M/Msun)$-$6.34[0.435]

(correlation coefficient of 0.60 and p-value of 8.75e-04) and,

log(Lm/Lsun)$=$0.57[0.21]log(n(H2))$-$7.25[0.75]

(correlation coefficient of 0.44 and p-value of 9e-03). These fits demonstrate
that the luminosity of the class I methanol masers depends on the physical
properties of the associated clump: the more massive and denser the clump, the
stronger the class I methanol emission. We checked for correlations between
the mass and density of clump with the distance, but found no significant
correlation in either source property (mass or density) with distance. This
suggests that the observed dependence between the 1.1 mm source properties and
class I maser luminosity is intrinsic and not an observational artefact.

Interestingly, the dependence between the luminosity of class I methanol
masers and the gas density of the associated mm dust clump is opposite to the
relationship observed between the luminosity of class II methanol masers and
the gas density of mm dust clump reported by Breen et al. (2010a). Breen et
al. found the more luminous 6.7 GHz class II methanol masers to be associated
with mm dust clumps with lower H2 density, i.e. there is a negative
correlation between them. Even though their results were derived with the peak
luminosity rather than integrated luminosity of class II methanol masers, the
peak luminosity and integrated luminosity are positively correlated. The
simplest picture which fits the different dependence between the luminosity of
class I and class II methanol masers with the gas density of the clump, is if
the intensity of class II methanol masers increases as the source
evolves/warms, while the class I maser intensity decreases as the outflow
broadens. If this is the case then we would expect to see an anti-correlation
in the class I/II flux densities. However, comparing the peak flux density of
class I and class II methanol masers for our observed EGO sample, we have
already shown that there is no statistically significant correlation between
them (see Figure 3).

We performed a similar analysis to that undertaken for the class I masers
associated with EGOs to check the relationship between the peak luminosity of
6.7 GHz class II methanol maser and the gas mass/density of the associated
dust clump for the 21 EGOs associated with both class I and II methanol masers
(listed in Table 7). We also found that there is a significant positive
correlation between the peak luminosity of the 6.7 GHz class II methanol maser
and mass of the associated dust clump (a slope of 1.21 with a standard error
of 0.32 and a p-value of 0.001 which allows us to reject the null hypothesis
of zero slope). The correlation coefficient between the points was measured to
be 0.66 for this linear regression analysis. But there is no statistical
correlation between the peak luminosity of 6.7 GHz maser and the gas density
(the linear regression analysis shows a slope of -0.38 with a large p-value of
0.57 and a small correlation coefficient of 0.15). The absence of correlation
between the peak luminosity of 6.7 GHz masers and gas density measured in our
analysis is not consistent with that of the anti-correlation between these
quantities found by Breen et al. (2010a). However the sample size for this
analysis is small and the class II masers are clustered in a small range of
parameter space with lower gas density (log(n(H2))$<$4), whereas the sample
shown in Figure 2 of Breen et al. covers a much wider range of gas densities.
Thus our class II maser sample is likely not representative of the larger
population. The correlation between the class I maser luminosity and gas
density is tighter than that measured for the 6.7 class II masers in our
analysis. The most likely explanation for this is that the gas density of the
clump is measured over a large spatial scale (the angular resolution of the
observations was typically 30′′), which can not accurately reflect the
properties of the smaller compact regions (of the order of 1′′) associated
with class II methanol masers. In contrast the class I methanol maser spots
usually have much larger angular and spatial distributions (usually at the
order of 10′′) and are associated with shocked regions (e.g. Cyganowski et al.
2009). Thus we might expect that the gas densities derived from dust clumps
should correlate more closely with class I methanol maser properties. The
dependence of class I maser luminosity on clump properties makes sense if the
class I masers are excited at the interface between outflows and surrounding
material. Future arcsecond resolution mm continuum imaging of these sources
will be necessary to determine if the relationship between the class II maser
properties and the associated gas and dust is tighter when the spatial scales
are comparable.

It is interesting to note that all of the sources associated with only class I
methanol masers are located in the bottom-left corner of the right panel in
Figure 8. This location corresponds to sources with a lower maser luminosity
and lower density of the dust clump. The left panel of Figure 8 shows that
median mass properties are also different between the population associated
with only class I masers and that associated with both class I and II masers:
the population associated with both class I and II masers can extend to higher
clump masses than that associated with only class I masers. The most widely
accepted mechanism for massive star formation suggests that high-mass sources
are believed to originate from massive clumps in the fragmentation of the
giant molecular cloud. The stellar mass of the sources is set by the
fragmentation process and the reservoir of material available to accrete is
determined by that as well (e.g. Hennebelle & Chabrier 2008). Therefore the
measured distribution of 1.1 mm clump mass among different populations
indicates that these class II methanol maser EGO sources may be associated
with a higher stellar mass range than those where only class I methanol masers
are also observed. However, it is also consistent with the predictions of the
two-evolutionary phase hypothesis for the class I only sources as the density
of the associated gas and dust decreases as the sources evolve (Breen et al.
2010a; 2010b). So in the two-evolutionary phase hypothesis the class I only
sources (i.e. the later evolutionary sources) should have a lower density than
sources with only class II masers or with both class I and II methanol masers
(see the more detailed discussions of this in Section 4.2). The assumed
constant dust temperature (Tdust) of 20 K in our calculations will affect the
results. However if the sources which are thought to be more evolved (i.e.
only class I maser sources) have a higher dust temperature, it would result in
a larger $B_{\nu}(T_{dust})$, thus a smaller mass and lower density of dust
clump associated with only class I masers. So this is also credible in the
two-evolutionary phase hypothesis.

However it must be noted that only 7 of the 31 class I maser-only sources have
estimates for the mass and density parameters from mm dust continuum
observations. The small size of this sample means that it may not be
representative of the entire population of class I maser-only EGOs. Moreover
some sources associated with both class I and class II methanol masers also
extend to the left-bottom corner of each panel in Figure 8. This suggests that
a small fractional of the class II methanol maser population can also appear
in an environment of comparable mass and dust clump density to that seen in
the class I only associated EGOs. However, Figure 8 clearly shows that the
class II methanol masers are usually associated with more massive and dense
dust clumps than those associated with only class I methanol masers.

##  5 Conclusions

Using the Mopra telescope, we have performed a systematic search for 95 GHz
class I methanol masers toward EGOs. EGOs are new MYSO candidates with ongoing
outflows identified from the _Spitzer_ GLIMPSE I survey. We detected 105 new
95 GHz masers from a sample of 192 targets. Of these, 92 have no previously
observed class I methanol maser activity, while the remaining 13 sources have
been detected in the 44 GHz transition. Thus our single-dish survey proves
that there is indeed a high detection rate ($\sim$55%) of class I methanol
masers in EGOs. Our findings increase the number of published class I methanol
masers to 290 (an additional 92 on top of the $\sim$198 from Val’tts & Larinov
2010). Mid-IR color analysis shows that the color-color region occupied by the
GLIMPSE point sources for EGOs which are and are not associated with class I
methanol masers are very similar, and mostly located in ranges
-0.6$<$[5.8]-[8.0]$<$1.4 and 0.5$<$[3.6]-[4.5]$<$4.0 (see section 4.1 for
detailed discussion of the uncertainties involved in this analysis). We find
that the detection rate of class I methanol maser is likely to be higher in
those sources with redder GLIMPSE point source colors.

Comparison of the [3.6]-[5.8] vs. [8.0]-[24] colors determined with integrated
fluxes from Cyganowski et al. (2008) for the subsamples of the EGOs based on
which class of methanol masers they are associated with, shows that those
which are only associated class I methanol masers extend to less red colors
than those associated with both classes of methanol maser. We suggest that the
less red colors of class I methanol maser only EGOs is either because the
class I only EGOs are associated with lower stellar mass objects, or because
class I maser emission arises at more than one evolutionary phase of the high-
mass star formation process. On the basis of current observations both
scenarios can be plausibly argued and further observations will be required to
determine which, if either of these hypotheses is correct. The thermal
molecular line observations taken in conjunction with our maser search will be
useful for trying to determine which of these scenarios is more likely. It
will also be important to undertake high resolution observations of the class
I maser emission in EGOs which are only associated with class I methanol
masers to determine where the maser emission arises relative to the EGO. These
observations are required to rule out the possibility that these sources
represent a sample of chance associations between the EGOs and class I masers.

Analysis of the properties of mm dust clumps associated with class I methanol
masers (for a subset of the EGOs in the class I maser survey sample which have
available millimeter continuum data) shows that the luminosity of the class I
methanol masers is correlated with the both the mass and density of the
associated dust clump. The more massive and denser the clump, the stronger the
class I methanol emission will be. We also find that the EGOs which are only
associated with class I methanol masers have a lower maser luminosity and
mass/density of dust clump. This finding supports either the hypothesis that
the class I maser can trace a population with lower stellar masses, or that
class I methanol masers may be associated with more than one evolutionary
phase during the formation of a high-mass star.

We thank Dr. Karl Menten and an anonymous referee for their helpful comments
on this paper. We are grateful to the staff of the ATNF for their assistance
in the observation. The Mopra telescope is operated through a collaborative
arrangement between the University of New South Wales and the CSIRO. This
research has made use of the SIMBAD database, operated at CDS, Strasbourg,
France, and the data products from the GLIMPSE survey, which is a legacy
science program of the Spitzer Space Telescope, funded by the National
Aeronautics and Space Administration. This work was supported in part by the
National Natural Science Foundation of China (grants 11073041, 10803017,
10625314, 10633010 and 10821302), the Knowledge Innovation Program of the
Chinese Academy of Sciences (Grant No. KJCX2-YW-T03), the National Key Basic
Research Development Program of China (No. 2007CB815405), and the CAS/SAFEA
International Partnership Program for Creative Research Teams.

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Table 1: Sample parameters

| Positiona |  |  |  |  |  |  |
---|---|---|---|---|---|---|---|---
Source | R.A. (2000) | Dec. (2000) | IRDCb | Class IIc | OHd | UC Hiid | mm d | Remarke | class If
| (h m s) | (° ′ ″) |  |  |  |  |  |  |
G10.29$-$0.13l | 18 08 49.3 |  $-$20 05 57 | Y | Y | – | N | Y | 2 | Y
G10.34$-$0.14l | 18 09 00.0 |  $-$20 03 35 | Y | Y | – | N | Y | 2 | Y
G11.11$-$0.11${}^{i^{\ast}}$${}^{m^{\dagger}}$ | 18 10 28.3 |  $-$19 22 31 | Y | Y | – | N | Y | 3 | N
G11.92$-$0.61g${}^{h^{\ast}}$${}^{l^{\dagger}}$ | 18 13 58.1 |  $-$18 54 17 | Y | Y | – | – | – | 1 | Y
G12.02$-$0.21ik | 18 12 40.4 |  $-$18 37 11 | Y | N | – | N | Y | 1 | N
G12.20$-$0.03jl | 18 12 23.6 |  $-$18 22 54 | N | Y | – | Y | Y | 4 | Y
G12.42$+$0.50n | 18 10 51.1 |  $-$17 55 50 | N | N | – | – | Y | 4 | Y
G12.68$-$0.18l | 18 13 54.7 |  $-$18 01 47 | N | Y | Y | N | Y | 4 | Y
G12.91$-$0.03${}^{h^{\ast}}$${}^{j^{\ast}}$${}^{l^{\dagger}}$ | 18 13 48.2 |  $-$17 45 39 | Y | Y | – | N | Y | 1 | Y
G12.91$-$0.26l | 18 14 39.5 |  $-$17 52 00 | N | Y | Y | N | Y | 5 | Y
G14.63$-$0.58hjl | 18 19 15.4 |  $-$16 30 07 | Y | Y | – | – | Y | 1 | Y
G16.58$-$0.08k | 18 21 15.0 |  $-$14 33 02 | Y | N | – | N | Y | 4 | N
G17.96$+$0.08k | 18 23 21.0 |  $-$13 15 11 | N | N | – | N | Y | 4 | N
IRDC18223$-$3n | 18 25 08.5 |  $-$12 45 23 | Y | N | – | N | Y | – | Y
G18.67$+$0.03h${}^{j^{\ast}}$${}^{l^{\dagger}}$ | 18 24 53.7 |  $-$12 39 20 | N | Y | – | N | Y | 1 | Y
G18.89$-$0.47h${}^{j^{\ast}}$${}^{l^{\dagger}}$ | 18 27 07.9 |  $-$12 41 36 | Y | Y | – | – | Y | 1 | Y
G19.01$-$0.03h${}^{j^{\ast}}$${}^{l^{\dagger}}$ | 18 25 44.8 |  $-$12 22 46 | Y | Y | – | N | Y | 1 | Y
G19.36$-$0.03l | 18 26 25.8 |  $-$12 03 57 | Y | Y | – | Y | Y | 2 | Y
G19.61$-$0.12m | 18 27 13.6 |  $-$11 53 20 | N | Y | – | N | N | 2 | N
G19.88$-$0.53hj${}^{l^{\dagger}}$ | 18 29 14.7 |  $-$11 50 23 | Y | Y | – | – | Y | 1 | Y
G20.24$+$0.07g${}^{k^{\ast}}$m | 18 27 44.6 |  $-$11 14 54 | N | Y | – | N | Y | 4 | N
G21.24$+$0.19k | 18 29 10.2 |  $-$10 18 11 | Y | N | – | N | Y | 4 | N
G22.04$+$0.22${}^{h^{\ast}}$${}^{j^{\ast}}$${}^{l^{\dagger}}$ | 18 30 34.7 |  $-$09 34 47 | Y | Y | – | N | Y | 1 | Y
G23.82$+$0.38 | 18 33 19.5 |  $-$07 55 37 | N | – | – | N | Y | 4 | Y
G23.96$-$0.11${}^{h^{\ast}}$${}^{j^{\ast}}$${}^{l^{\dagger}}$ | 18 35 22.3 |  $-$08 01 28 | N | Y | – | N | Y | 1 | Y
G24.00$-$0.10${}^{h^{\ast}}$${}^{j^{\ast}}$${}^{l^{\dagger}}$ | 18 35 23.5 |  $-$07 59 32 | Y | Y | – | N | Y | 1 | Y
G24.11$-$0.17n | 18 35 52.6 |  $-$07 55 17 | Y | N | – | N | Y | 4 | Y
G24.17$-$0.02i | 18 35 25.0 |  $-$07 48 15 | Y | – | – | N | N | 1 | N
G24.33$+$0.14g${}^{j^{\ast}}$l | 18 35 08.1 |  $-$07 35 04 | Y | Y | – | N | Y | 4 | Y
G24.63$+$0.15${}^{h^{\ast}}$j${}^{n^{\dagger}}$ | 18 35 40.1 |  $-$07 18 35 | Y | N | – | N | Y | 3 | Y
G24.94$+$0.07h${}^{l^{\dagger}}$ | 18 36 31.5 |  $-$07 04 16 | N | Y | – | N | Y | 1 | Y
G25.27$-$0.43${}^{h^{\ast}}$j${}^{l^{\dagger}}$ | 18 38 57.0 |  $-$07 00 48 | Y | Y | – | – | Y | 1 | Y
G25.38$-$0.15j | 18 38 08.1 |  $-$06 46 53 | Y | – | – | N | Y | 2 | Y
G27.97$-$0.47h${}^{n^{\dagger}}$ | 18 44 03.6 |  $-$04 38 02 | Y | N | – | – | Y | 1 | Y
G28.28$-$0.36m | 18 44 13.2 |  $-$04 18 04 | N | Y | – | Y | Y | 2 | N
G28.85$-$0.23m | 18 44 47.5 |  $-$03 44 15 | N | Y | – | N | N | 4 | N
G29.89$-$0.77 | 18 48 37.7 |  $-$03 03 44 | Y | N | – | – | N | 4 | N
G29.91$-$0.81 | 18 48 47.6 |  $-$03 03 31 | N | N | – | – | Y | 4 | N
G29.96$-$0.79ik | 18 48 50.0 |  $-$03 00 21 | Y | N | – | – | Y | 3 | N
G34.26$+$0.15g | 18 53 16.4 |  $+$01 15 07 | N | – | – | Y | Y | 5 | Y
G34.28$+$0.18h | 18 53 15.0 |  $+$01 17 11 | Y | – | – | N | Y | 3 | Y
G34.39$+$0.22${}^{j^{\ast}}$ | 18 53 19.0 |  $+$01 24 08 | Y | – | – | N | N | 2 | Y
G34.41$+$0.24h${}^{j^{\ast}}$ | 18 53 17.9 |  $+$01 25 25 | Y | – | – | N | Y | 1 | Y
G35.04$-$0.47hj${}^{n^{\dagger}}$ | 18 56 58.1 |  $+$01 39 37 | Y | N | – | – | Y | 1 | Y
G35.13$-$0.74h | 18 58 06.4 |  $+$01 37 01 | N | – | – | – | – | 1 | Y
G35.15$+$0.80i | 18 52 36.6 |  $+$02 20 26 | N | N | – | – | – | 1 | N
G35.20$-$0.74h${}^{l^{\dagger}}$ | 18 58 12.9 |  $+$01 40 33 | N | Y | – | – | – | 1 | Y
G35.68$-$0.18ik | 18 57 05.0 |  $+$02 22 00 | Y | N | – | N | Y | 1 | N
G35.79$-$0.17hj | 18 57 16.7 |  $+$02 27 56 | Y | – | – | N | Y | 1 | Y
G36.01$-$0.20${}^{i^{\ast}}$${}^{k^{\ast}}$ | 18 57 45.9 |  $+$02 39 05 | Y | – | – | N | Y | 1 | N
G37.48$-$0.10ik${}^{m^{\dagger}}$ | 19 00 07.0 |  $+$03 59 53 | N | Y | – | N | Y | 1 | N
G37.55$+$0.20 | 18 59 07.5 |  $+$04 12 31 | N | – | – | N | N | 5 | N
G39.10$+$0.49${}^{h^{\ast}}$j${}^{l^{\dagger}}$ | 19 00 58.1 |  $+$05 42 44 | N | Y | – | – | Y | 1 | Y
G39.39$-$0.14 | 19 03 45.3 |  $+$05 40 43 | N | – | – | Y | Y | 4 | Y
G40.28$-$0.22hj | 19 05 41.3 |  $+$06 26 13 | Y | – | – | – | Y | 3 | Y
G40.28$-$0.27ik | 19 05 51.5 |  $+$06 24 39 | Y | N | – | – | Y | 1 | N
G40.60$-$0.72jn | 19 08 03.3 |  $+$06 29 15 | N | N | – | – | – | 4 | Y
G44.01$-$0.03ik | 19 11 57.2 |  $+$09 50 05 | N | N | – | – | N | 1 | N
G45.47$+$0.05gi | 19 14 25.6 |  $+$11 09 28 | Y | – | – | Y | Y | 1 | N
G45.50$+$0.12k | 19 14 13.0 |  $+$11 13 30 | N | – | – | – | N | 4 | N
G45.80$-$0.36h | 19 16 31.1 |  $+$11 16 11 | N | – | – | – | Y | 3 | Y
G48.66$-$0.30 | 19 21 48.0 |  $+$13 49 21 | Y | N | – | – | Y | 2 | N
G49.07$-$0.33${}^{h^{\ast}}$j${}^{n^{\dagger}}$ | 19 22 41.9 |  $+$14 10 12 | Y | N | – | – | Y | 3 | Y
G49.42$+$0.33m | 19 20 59.1 |  $+$14 46 53 | N | Y | – | – | Y | 2 | N
G53.92$-$0.07i | 19 31 23.0 |  $+$18 33 00 | N | N | – | – | Y | 3 | N
G54.11$-$0.04k | 19 31 40.0 |  $+$18 43 53 | N | N | – | – | Y | 4 | N
G54.11$-$0.08ik | 19 31 48.8 |  $+$18 42 57 | N | N | – | – | Y | 3 | N
G54.45$+$1.01hj${}^{n^{\dagger}}$ | 19 28 26.4 |  $+$19 32 15 | N | N | – | – | – | 3 | Y
G57.61$+$0.02 | 19 38 40.8 |  $+$21 49 35 | N | – | – | – | N | 4 | N
G59.79$+$0.63hj | 19 41 03.1 |  $+$24 01 15 | Y | – | – | – | – | 1 | Y
G298.90$+$0.36ik | 12 16 43.2 |  $-$62 14 25 | N | N | – | – | – | 1 | N
G304.89$+$0.64ik | 13 08 12.1 |  $-$62 10 22 | Y | N | – | – | – | 3 | N
G305.48$-$0.10h | 13 13 45.8 |  $-$62 51 28 | N | – | – | – | – | 1 | Y
G305.52$+$0.76${}^{h^{\ast}}$j${}^{n^{\dagger}}$ | 13 13 29.3 |  $-$61 59 53 | Y | N | – | – | – | 1 | Y
G305.57$-$0.34i${}^{k^{\ast}}$ | 13 14 49.1 |  $-$63 05 38 | Y | – | – | – | – | 1 | N
G305.62$-$0.34i | 13 15 11.5 |  $-$63 05 30 | N | – | – | – | – | 1 | N
G305.77$-$0.25 | 13 16 30.0 |  $-$62 59 09 | N | N | – | – | – | 4 | N
G305.80$-$0.24gjl | 13 16 43.4 |  $-$62 58 29 | N | Y | Y | Y | – | 4 | Y
G305.82$-$0.11hj | 13 16 48.6 |  $-$62 50 35 | Y | – | – | – | – | 1 | Y
G305.89$+$0.02h${}^{l^{\dagger}}$ | 13 17 15.5 |  $-$62 42 24 | Y | Y | – | – | – | 1 | Y
G309.15$-$0.35ik | 13 45 51.3 |  $-$62 33 46 | Y | N | – | – | – | 1 | N
G309.90$+$0.23k | 13 51 00.4 |  $-$61 49 53 | Y | – | – | – | – | 2 | N
G309.91$+$0.32${}^{h^{\ast}}$j | 13 50 53.9 |  $-$61 44 22 | Y | – | – | – | – | 3 | Y
G309.97$+$0.50k | 13 51 05.2 |  $-$61 33 20 | Y | – | – | – | – | 4 | N
G309.97$+$0.59ik | 13 50 52.6 |  $-$61 27 46 | Y | – | – | – | – | 3 | N
G309.99$+$0.51i${}^{k^{\ast}}$ | 13 51 12.2 |  $-$61 32 09 | Y | – | – | – | – | 1 | N
G310.08$-$0.23i | 13 53 23.0 |  $-$62 14 13 | Y | N | – | – | – | 1 | N
G310.15$+$0.76l | 13 51 59.2 |  $-$61 15 37 | N | Y | – | – | – | 4 | Y
G310.38$-$0.30n | 13 56 01.0 |  $-$62 14 19 | Y | N | – | – | – | 4 | Y
G311.04$+$0.69n | 13 59 18.1 |  $-$61 06 33 | Y | N | – | – | – | 4 | Y
G311.51$-$0.45hj${}^{n^{\dagger}}$ | 14 05 46.1 |  $-$62 04 49 | Y | N | – | – | – | 3 | Y
G312.11$+$0.26ik${}^{m^{\dagger}}$ | 14 08 49.3 |  $-$61 13 25 | Y | Y | N | – | – | 1 | N
G313.71$-$0.19m | 14 22 37.4 |  $-$61 08 17 | Y | Y | Y | – | – | 4 | N
G313.76$-$0.86l | 14 25 01.3 |  $-$61 44 57 | Y | Y | Y | Y | – | 4 | Y
G317.44$-$0.37 | 14 51 03.0 |  $-$59 49 58 | Y | – | N | – | – | 4 | N
G317.46$-$0.40ik | 14 51 19.6 |  $-$59 50 51 | Y | – | N | – | – | 1 | N
G317.87$-$0.15hj${}^{n^{\dagger}}$ | 14 53 16.3 |  $-$59 26 36 | Y | N | N | – | – | 1 | Y
G317.88$-$0.25hj${}^{n^{\dagger}}$ | 14 53 43.5 |  $-$59 31 35 | Y | N | N | – | – | 1 | Y
G320.23$-$0.28gl | 15 09 52.6 |  $-$58 25 36 | Y | Y | Y | – | – | 2 | Y
G321.94$-$0.01hj${}^{n^{\dagger}}$ | 15 19 43.3 |  $-$57 18 06 | Y | N | N | – | – | 1 | Y
G324.11$+$0.44ik | 15 31 05.0 |  $-$55 43 39 | Y | N | N | – | – | 3 | N
G324.17$+$0.44 | 15 31 24.6 |  $-$55 41 30 | N | N | N | – | – | 2 | N
G324.19$+$0.41hj${}^{n^{\dagger}}$ | 15 31 38.0 |  $-$55 42 36 | N | N | N | – | – | 1 | Y
G325.52$+$0.42 | 15 39 10.6 |  $-$54 55 40 | N | N | N | – | – | 4 | N
G326.27$-$0.49i | 15 47 10.8 |  $-$55 11 12 | Y | N | N | – | – | 1 | N
G326.31$+$0.90ik | 15 41 35.9 |  $-$54 03 42 | Y | N | N | – | – | 1 | N
G326.32$-$0.39${}^{j^{\ast}}$ | 15 47 04.8 |  $-$55 04 51 | N | – | N | – | – | 2 | Y
G326.36$+$0.88ik | 15 41 55.4 |  $-$54 02 55 | Y | – | N | – | – | 3 | N
G326.37$+$0.94 | 15 41 44.1 |  $-$54 00 00 | Y | N | N | – | – | 4 | N
G326.41$+$0.93hj | 15 41 59.4 |  $-$53 59 03 | Y | – | N | – | – | 3 | Y
G326.57$+$0.20ik | 15 45 53.4 |  $-$54 27 50 | N | N | N | – | – | 3 | N
G326.61$+$0.80hj${}^{n^{\dagger}}$ | 15 43 36.2 |  $-$53 57 51 | Y | N | N | – | – | 3 | Y
G326.78$-$0.24gi | 15 48 55.2 |  $-$54 40 37 | N | N | N | – | – | 1 | N
G326.79$+$0.38ik | 15 46 20.9 |  $-$54 10 45 | Y | N | N | – | – | 1 | N
G326.80$+$0.51ik | 15 45 48.6 |  $-$54 04 30 | Y | N | N | – | – | 3 | N
G326.92$-$0.31hj${}^{n^{\dagger}}$ | 15 49 56.2 |  $-$54 38 29 | Y | N | N | – | – | 3 | Y
G326.97$-$0.03hj${}^{n^{\dagger}}$ | 15 49 03.2 |  $-$54 23 37 | Y | N | N | – | – | 1 | Y
G327.57$-$0.85 | 15 55 47.3 |  $-$54 39 09 | Y | – | N | – | – | 4 | Y
G327.65$+$0.13 | 15 52 00.5 |  $-$53 50 41 | N | N | N | – | – | 4 | N
G327.72$-$0.38h | 15 54 32.3 |  $-$54 11 55 | N | – | N | – | – | 3 | Y
G327.86$+$0.19ik | 15 52 49.2 |  $-$53 40 07 | N | N | N | – | – | 3 | N
G327.89$+$0.15hj${}^{n^{\dagger}}$ | 15 53 10.3 |  $-$53 40 28 | Y | N | N | – | – | 3 | Y
G328.16$+$0.59jn | 15 52 42.5 |  $-$53 09 51 | N | N | N | – | – | 4 | Y
G328.55$+$0.27hj${}^{n^{\dagger}}$ | 15 56 01.5 |  $-$53 09 44 | Y | N | N | – | – | 3 | Y
G328.60$+$0.27k | 15 56 15.8 |  $-$53 07 50 | Y | N | N | – | – | 4 | N
G329.16$-$0.29hj | 16 01 33.6 |  $-$53 11 15 | Y | – | N | – | – | 3 | Y
G329.47$+$0.52${}^{h^{\ast}}$${}^{j^{\ast}}$ | 15 59 36.6 |  $-$52 22 55 | Y | – | N | – | – | 1 | Y
G330.88$-$0.37gl | 16 10 19.9 |  $-$52 06 13 | Y | Y | Y | Y | – | 2 | Y
G331.08$-$0.47ik | 16 11 46.9 |  $-$52 02 31 | Y | N | N | – | – | 3 | N
G331.12$-$0.46k | 16 11 55.3 |  $-$52 00 10 | Y | N | N | – | – | 4 | N
G331.37$-$0.40hj | 16 12 48.1 |  $-$51 47 30 | Y | – | N | – | – | 3 | Y
G331.51$-$0.34 | 16 13 11.7 |  $-$51 39 12 | Y | – | N | – | – | 4 | N
G331.62$+$0.53h${}^{n^{\dagger}}$ | 16 09 56.8 |  $-$50 56 25 | N | N | N | – | – | 3 | Y
G331.71$+$0.58hj | 16 10 06.3 |  $-$50 50 29 | Y | – | N | – | – | 3 | Y
G331.71$+$0.60hj | 16 10 01.9 |  $-$50 49 33 | Y | – | N | – | – | 3 | Y
G332.12$+$0.94${}^{k^{\ast}}$ | 16 10 30.4 |  $-$50 18 05 | Y | N | N | – | – | 2 | N
G332.28$-$0.07ik | 16 15 35.1 |  $-$50 55 36 | Y | – | N | – | – | 3 | N
G332.28$-$0.55${}^{j^{\ast}}$n | 16 17 41.8 |  $-$51 16 04 | Y | N | N | – | – | 4 | Y
G332.33$-$0.12ik | 16 16 03.3 |  $-$50 55 34 | Y | N | N | – | – | 3 | N
G332.35$-$0.12h${}^{l^{\dagger}}$ | 16 16 07.0 |  $-$50 54 30 | Y | Y | Y | – | – | 1 | Y
G332.36$+$0.60hj${}^{n^{\dagger}}$ | 16 13 02.4 |  $-$50 22 39 | Y | N | N | – | – | 3 | Y
G332.47$-$0.52i | 16 18 26.5 |  $-$51 07 12 | Y | N | N | – | – | 3 | N
G332.58$+$0.15hj | 16 16 00.6 |  $-$50 33 30 | Y | – | N | – | – | 3 | Y
G332.59$+$0.04ik | 16 16 30.1 |  $-$50 37 50 | Y | N | N | – | – | 3 | N
G332.81$-$0.70hj | 16 20 48.1 |  $-$51 00 15 | N | – | N | – | – | 1 | Y
G332.91$-$0.55${}^{h^{\ast}}$j${}^{n^{\dagger}}$ | 16 20 32.6 |  $-$50 49 46 | Y | N | N | – | – | 3 | Y
G333.08$-$0.56i${}^{k^{\ast}}$ | 16 21 20.9 |  $-$50 43 05 | Y | – | N | – | – | 3 | N
G333.32$+$0.10${}^{j^{\ast}}$l | 16 19 28.9 |  $-$50 04 40 | Y | Y | Y | – | – | 4 | Y
G334.04$+$0.35ik | 16 21 36.9 |  $-$49 23 28 | N | N | N | – | – | 3 | N
G335.43$-$0.24${}^{i^{\ast}}$k | 16 30 05.8 |  $-$48 48 44 | Y | – | N | – | – | 3 | N
G335.59$-$0.30j | 16 31 02.5 |  $-$48 44 07 | Y | – | N | – | – | 4 | Y
G336.02$-$0.83l | 16 35 09.7 |  $-$48 46 44 | N | Y | Y | Y | – | 4 | Y
G336.03$-$0.82 | 16 35 09.6 |  $-$48 45 55 | N | – | N | Y | – | 4 | Y
G336.87$+$0.29ik | 16 33 40.3 |  $-$47 23 32 | Y | N | N | – | – | 3 | N
G336.96$-$0.98hj${}^{n^{\dagger}}$ | 16 39 37.5 |  $-$48 10 58 | Y | N | N | – | – | 3 | Y
G337.16$-$0.39i | 16 37 49.6 |  $-$47 38 50 | Y | – | N | – | – | 3 | N
G337.30$-$0.87${}^{h^{\ast}}$ | 16 40 31.3 |  $-$47 51 31 | Y | – | N | – | – | 1 | Y
G338.32$-$0.41${}^{h^{\ast}}$j | 16 42 27.5 |  $-$46 46 57 | Y | – | N | – | – | 3 | Y
G338.39$-$0.40${}^{i^{\ast}}$ | 16 42 41.2 |  $-$46 43 40 | Y | – | N | – | – | 1 | N
G338.42$-$0.41${}^{k^{\ast}}$ | 16 42 50.5 |  $-$46 42 29 | Y | – | N | – | – | 4 | N
G339.58$-$0.13l | 16 45 59.5 |  $-$45 38 44 | Y | Y | N | – | – | 4 | Y
G339.95$-$0.54h${}^{l^{\dagger}}$ | 16 49 07.9 |  $-$45 37 59 | N | Y | N | – | – | 1 | Y
G340.05$-$0.25l | 16 48 14.7 |  $-$45 21 52 | Y | Y | Y | Y | – | 4 | Y
G340.07$-$0.24 | 16 48 15.1 |  $-$45 20 57 | Y | – | N | – | – | 4 | N
G340.10$-$0.18 | 16 48 07.0 |  $-$45 17 06 | N | – | N | – | – | 4 | N
G340.75$-$1.00ik | 16 54 04.0 |  $-$45 18 50 | Y | N | N | – | – | 3 | N
G340.77$-$0.12ik | 16 50 17.5 |  $-$44 43 54 | Y | – | N | – | – | 3 | N
G340.97$-$1.02${}^{h^{\ast}}$${}^{j^{\ast}}$ | 16 54 57.3 |  $-$45 09 04 | Y | – | N | – | – | 1 | Y
G341.20$-$0.26ik | 16 52 27.8 |  $-$44 29 29 | Y | – | N | – | – | 3 | N
G341.22$-$0.26 | 16 52 32.2 |  $-$44 28 38 | Y | – | N | – | – | 2 | Y
G341.24$-$0.27hj | 16 52 37.3 |  $-$44 28 09 | Y | – | N | – | – | 1 | Y
G341.99$-$0.10${}^{i^{\ast}}$ | 16 54 32.8 |  $-$43 46 45 | Y | N | N | – | – | 1 | N
G342.04$+$0.43 | 16 52 27.8 |  $-$43 24 17 | N | N | N | – | – | 4 | N
G342.15$+$0.51hj${}^{n^{\dagger}}$ | 16 52 28.3 |  $-$43 16 08 | N | N | N | – | – | 3 | Y
G342.48$+$0.18l | 16 55 02.6 |  $-$43 13 01 | Y | Y | N | – | – | 2 | Y
G343.19$-$0.08ik | 16 58 34.9 |  $-$42 49 46 | Y | N | N | – | – | 3 | N
G343.40$-$0.40ik | 17 00 40.4 |  $-$42 51 33 | Y | N | N | – | – | 3 | N
G343.42$-$0.37k | 17 00 37.4 |  $-$42 49 40 | Y | N | N | – | – | 4 | N
G343.50$+$0.03h${}^{j^{\ast}}$${}^{n^{\dagger}}$ | 16 59 10.7 |  $-$42 31 07 | Y | N | N | – | – | 3 | Y
G343.50$-$0.47hj | 17 01 18.4 |  $-$42 49 36 | N | – | N | – | – | 1 | Y
G343.53$-$0.51j | 17 01 33.5 |  $-$42 49 50 | Y | – | N | – | – | 4 | Y
G343.72$-$0.18i | 17 00 48.3 |  $-$42 28 25 | Y | – | N | – | – | 1 | N
G343.78$-$0.24${}^{i^{\ast}}$ | 17 01 13.1 |  $-$42 27 48 | Y | N | N | – | – | 3 | N
G344.21$-$0.62ik | 17 04 17.8 |  $-$42 21 09 | N | N | N | – | – | 3 | N
G345.13$-$0.17jl | 17 05 23.1 |  $-$41 21 11 | N | Y | N | – | – | 4 | Y
G345.72$+$0.82ik | 17 03 06.4 |  $-$40 17 09 | Y | N | N | – | – | 1 | N
G345.99$-$0.02${}^{h^{\ast}}$${}^{l^{\dagger}}$ | 17 07 27.6 |  $-$40 34 45 | N | Y | N | – | – | 1 | Y
G346.04$+$0.05m | 17 07 19.9 |  $-$40 29 49 | N | Y | N | – | – | 4 | N
G348.17$+$0.46hj${}^{n^{\dagger}}$ | 17 12 10.9 |  $-$38 31 59 | N | N | N | – | – | 3 | Y
G348.55$-$0.98h${}^{l^{\dagger}}$ | 17 19 20.9 |  $-$39 03 55 | N | Y | Y | – | – | 1 | Y
G348.58$-$0.92h${}^{l^{\dagger}}$ | 17 19 10.7 |  $-$39 00 23 | Y | Y | Y | – | – | 1 | Y
G348.73$-$1.04gl | 17 20 06.5 |  $-$38 57 08 | Y | Y | Y | Y | – | 4 | Y

aafootnotetext: The targeted positions for the observations are the EGO
positions given in the EGO catalog of Cyganowski et al. (2008), with the
exception of IRDC18223$-$3, the position for which is from Beuther &
Steinacker (2007).

bbfootnotetext: Association with IR dark clouds, : Y = Yes, N = No, given by
Cyganowski et al. (2008).

ccfootnotetext: Associations with 6.7 GHz class II methanol masers within
30″identified from the 6.7 GHz maser catalogs (Cyganowski et al. 2009; Caswell
2009; Xu et al. 2009; Caswell et al. 2010; Green et al. 2010) and our recent
class II methanol maser surveys with the University of Tasmania Mt. Pleasant
26 m (Titmarsh et al. in prep.): “–” are sources for which 6.7 GHz maser
emission is detected in the Mt Pleasant survey, but for which accurate
positional information is not available, “Y” are sources with 6.7 GHz masers
with accurate positions from high-resolution observations, “N” are sources
without 6.7 GHz maser detections in the Mt Pleasant survey.

ddfootnotetext: Associations with OH masers, UC Hii regions and 1.1 mm
continuum sources within 30″: Y = Yes, N = No,“–” = no information, identified
from 1665 and 1667 MHz OH maser catalog (Caswell 1998), UC Hii catalogs (Wood
& Churchwell 1989; Becker et al. 1994; Kurtz et al. 1994; Walsh et al. 1998;
Cyganowski et al. 2009), and 1.1 mm continuum BOLOCAM GPS (BGPS) archive
(Rosolowsky et al. 2010).

eefootnotetext: Remarks: 1 – 5 represent that the sources are selected from
Tables 1 – 5 of Cyganowski et al. (2008), respectively. The source
IRDC18223$-$3 is selected from Beuther & Steinacker (2007). Sources from
tables 1, 2, and 5 and IRDC18223$-$3 are classified as “likely” outflow
candidates, while those from tables 3 and 4 are classified as ”possible”
outflow candidates in our analysis.

fffootnotetext: Detections with 95 GHz class I methanol masers in our
observations: Y = Yes, N = No.

ggfootnotetext: The sources have been included in Chen et al. sample (10
members in total).

h, ih, ifootnotetext: Represent the sources with and without 95 GHz class I
methanol maser detections in our survey respectively which are shown in the
[3.6]-[4.5] vs. [5.8]-[8.0] color-color diagram (Figure 4) obtained with
integrated fluxes from Table 1 and 3 of Cyganowski et al. (2008). A “$\ast$”
in the superscript marks the source which locates in the left-upper of the
color region and outside Stage I evolutionary zone derived by Robitaille et
al. (2006) (see Section 4.1 and Figure 4).

j, kj, kfootnotetext: Represent the sources with and without 95 GHz class I
methanol maser detections in our survey respectively which are plotted in the
[3.6]-[4.5] vs. [5.8]-[8.0] color-color diagram obtained with GLIMPSE point
source fluxes in Figure 5. A “$\ast$” in the superscript denotes the source
which lies in the region outside Stage I (see Section 4.1 and Figure 5).

l, m, nl, m, nfootnotetext: Represent the three different subsamples for the
IRAC and MIPS 24 $\mu$m color analysis with integrated fluxes of EGOs: l is a
source associated with both a class I methanol maser and a class II methanol
maser with an accurate position, m is a source associated with only a class II
maser (with an accurate position), and n is a source associated with only
class I maser emission. A “$\dagger$” in the superscript denotes the source
plotted in [3.6]-[5.8] versus [8.0]-[24] color diagram (Figure 6; see Section
4.2).

Table 2: Summary of the other datasets utilised in this work

Category | Datasets | (Un)Targeted | Area covered | Angular resolution | Sensitivitya | Commentsb
---|---|---|---|---|---|---
OH maser | Caswell (1998) | Untargeted |  $|b|<1^{\circ}$ & |  $\sim$ 7′′ |  $\sim$ 0.12 Jy | 101 EGOs fell within the area
|  |  | $l=312^{\circ}-356^{\circ}$ |  |  | 11 detected
|  | Targeted | $l=230^{\circ}-13^{\circ}$ |  $\sim$ 7′′ |  $\sim$ 0.12 Jy | additional 3 EGOs were detected
Class II maser | Caswell (2009) | Targeted | $l=188^{\circ}-50^{\circ}$ |  $\sim$ 2′′ | … |  $\sim$ 60 EGOs were detected
| Cyganowski et al. (2009) | Targeted | … |  $\sim$ 2′′ |  $\sim$ 0.1 Jy |  $\sim$ 20 EGOs were detected
| Xu et al. (2009) | Targeted | … | a few arcsecs | … |  $\sim$ 30 EGOs were detected
| Caswell et al. (2010) | Untargeted |  $|b|<2^{\circ}$ & | a few arcsecs |  $\sim$ 0.2 Jy | 11 EGOs fell within the area,
|  |  | $l=345^{\circ}-6^{\circ}$ |  |  | 8 were detected
| Green et al. (2010) | Unargeted |  $|b|<2^{\circ}$ & | a few arcsecs |  $\sim$ 0.2 Jy | 22 EGOs fell within the area,
|  |  | $l=6^{\circ}-20^{\circ}$ |  |  | 16 were detected
| Titmarsh et al. (in prep.) | Targeted | … |  $\sim$ 7′ |  $\sim$ 1.5 Jy | searched $\sim$ 140 EGOs without
|  |  |  |  |  | observed in previous survey,
|  |  |  |  |  |  $\sim$ 80 were not detected
UC Hii region | Wood & Churchwell (1989) | Targeted | … | 0.4′′ |  $\sim$ 1 mJy/beam at 6 cm | 2 EGOs were detected
| Becker et al. (1994) | Untargeted |  $|b|<0.4^{\circ}$ & |  $\sim$ 4′′ |  $\sim$ 7.5 mJy/beam at |  $\sim$ 40 EGOs fell within the area,
|  |  | $l=350^{\circ}-40^{\circ}$ |  | field center, 5 GHz | but only 4 were detected
| Kurtz et al. (1994) | Targeted | … |  $<$ 1′′ |  $\sim$ 1.2 mJy/beam at 2 cm | 1 EGO was detected
|  |  |  |  |  $\sim$ 0.6 mJy/beam at 3.6 cm |
| Walsh et al. (1998) | Targeted | … |  $\sim$ 1′′ |  $\sim$ 3 mJy at 8.64 GHz | 9 EGOs were detected
|  |  |  |  |  $\sim$ 30 mJy at 6.67 GHz |
| Cyganowski et al. (2009) | Targeted | … |  $\sim$ 0.5′′ |  $\sim$ 3 mJy/beam at 44 GHz | Among 19 surveyed EGOs,
|  |  |  |  |  | only 1 was detected
1.1 mm source | Rosolowsky et al. (2010) | Untargeted | $|b|<0.4^{\circ}$ | 33′′ |  $\sim$ 0.1-0.2 Jy | 63 EGOs fell within the area,
|  |  | $l=350^{\circ}-90^{\circ}$ |  |  | 54 were detected

aafootnotetext: The sensitivities quoted here are uniformly set to 3
$\sigma_{rms}$ for all surveys. For the Class II maser surveys of Caswell et
al. (2010) and Green et al. (2010), we quoted the sensitivity from the
subsequent ATCA observation for the Parkes MMB survey.

bbfootnotetext: Comments on the extent of overlap with our Morpa surveyed
EGOs, except for class II maser datasets that also include 51 EGOs listed in
our previous work (Chen et al. 2009) but which were not observed in our Mopra
survey (see Table 6).

Table 3: Observed properties of 95 GHz class I methanol maser sources
detected.

| Gaussian Fit |  |  |  |
---|---|---|---|---|---
Source | $S$ | VLSR | $\Delta V$ | $P$ | $\sigma_{rms}$ | Sint | D | Lm
| (Jy km s-1) | (km s-1) | (km s-1) | (Jy) | (Jy) | (Jy km s-1) | (kpc) | (10-6 L⊙)
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9)
G10.29-0.13 | 10.43(0.92) | 13.96(0.41) | 8.41(0.88) | 0.99 | 0.55 | 12.87 | 2.3 | 2.1
| 1.62(0.24) | 14.31(0.03) | 0.46(0.07) | 2.82 |  |  |  |
| 0.82(0.18) | 15.13(0.03) | 0.28(0.07) | 2.30 |  |  |  |
G10.34-0.14 | 39.05(0.81) | 12.24(0.05) | 5.30(0.12) | 6.92 | 0.62 | 69.21 | 2.3 | 11.5
| 30.16(0.26) | 14.74(0.00) | 0.45(0.00) | 63.05 |  |  |  |
G11.92-0.61 | 22.55(0.33) | 33.94(0.01) | 0.82(0.01) | 25.70 | 0.62 | 69.51 | 3.8 | 31.5
| 28.63(0.45) | 35.10(0.00) | 0.52(0.01) | 52.18 |  |  |  |
| 18.34(0.60) | 36.26(0.02) | 1.44(0.06) | 11.95 |  |  |  |
G12.20-0.03 | 1.93(0.28) | 49.28(0.04) | 0.59(0.11) | 3.05 | 0.63 | 7.08 | 4.5 | 4.5
| 0.92(0.23) | 49.96(0.03) | 0.32(0.08) | 2.69 |  |  |  |
| 1.26(0.43) | 51.11(0.04) | 0.47(0.12) | 2.52 |  |  |  |
| 2.97(0.70) | 52.36(0.23) | 2.04(0.55) | 1.37 |  |  |  |
G12.42+0.50 | 0.58(0.24) | 16.57(0.06) | 0.42(0.16) | 1.28 | 0.49 | 7.08 | 2.4 | 1.3
| 5.37(0.61) | 17.98(0.07) | 1.67(0.24) | 3.01 |  |  |  |
| 1.14(0.45) | 19.67(0.15) | 0.99(0.33) | 1.08 |  |  |  |
G12.68-0.18 | 7.97(0.37) | 55.25(0.06) | 2.64(0.14) | 2.84 | 0.45 | 7.97 | 4.7 | 5.5
G12.91-0.03 | 2.55(0.29) | 55.23(0.03) | 0.77(0.08) | 3.09 | 0.46 | 9.76 | 4.8 | 7.0
| 6.50(0.46) | 57.02(0.05) | 1.82(0.17) | 3.34 |  |  |  |
| 0.71(0.20) | 58.47(0.04) | 0.39(0.10) | 1.73 |  |  |  |
G12.91-0.26 | 15.63(0.76) | 36.99(0.09) | 3.57(0.23) | 4.12 | 0.53 | 19.55 | 3.8 | 8.8
| 1.52(0.22) | 36.58(0.02) | 0.35(0.05) | 4.01 |  |  |  |
| 2.40(0.54) | 39.42(0.05) | 0.96(0.16) | 2.34 |  |  |  |
G14.63-0.58 | 0.54(0.14) | 16.88(0.04) | 0.30(0.09) | 1.68 | 0.46 | 14.04 | 2.2 | 2.1
| 8.99(3.27) | 18.46(0.21) | 1.24(0.24) | 6.83 |  |  |  |
| 4.50(0.83) | 18.72(0.01) | 0.37(0.03) | 11.40 |  |  |  |
IRDC18223-3 | 3.32(0.82) | 45.55(0.70) | 6.25(1.87) | 0.50 | 0.60 | 6.32 | 3.6 | 2.6
| 1.36(0.41) | 44.83(0.09) | 0.73(0.23) | 1.75 |  |  |  |
| 1.65(0.33) | 45.65(0.04) | 0.50(0.10) | 3.11 |  |  |  |
G18.67+0.03 | 3.12(0.28) | 80.08(0.06) | 1.15(0.12) | 2.16 | 0.49 | 3.61 | 5.1 | 2.9
| 0.49(0.17) | 82.53(0.09) | 0.43(0.17) | 0.91 |  |  |  |
G18.89-0.47 | 16.30(0.62) | 64.75(0.01) | 1.02(0.04) | 12.75 | 0.62 | 46.53 | 4.5 | 29.5
| 14.64(0.41) | 66.01(0.01) | 0.52(0.01) | 22.57 |  |  |  |
| 2.78(0.34) | 66.85(0.02) | 0.44(0.05) | 5.04 |  |  |  |
| 12.81(1.13) | 66.59(0.30) | 6.34(0.59) | 1.61 |  |  |  |
G19.01-0.03 | 12.99(0.84) | 59.26(0.14) | 4.70(0.36) | 2.59 | 0.60 | 20.46 | 4.2 | 11.3
| 3.42(0.95) | 59.28(0.09) | 0.73(0.17) | 4.42 |  |  |  |
| 3.10(0.86) | 59.88(0.04) | 0.50(0.07) | 5.78 |  |  |  |
| 0.94(0.26) | 61.89(0.05) | 0.46(0.12) | 1.93 |  |  |  |
G19.36-0.03 | 22.96(1.14) | 26.61(0.05) | 3.83(0.18) | 5.63 | 0.49 | 68.67 | 2.5 | 13.5
| 32.40(0.95) | 26.48(0.01) | 1.07(0.02) | 28.41 |  |  |  |
| 13.32(0.45) | 27.59(0.01) | 0.66(0.02) | 18.95 |  |  |  |
G19.88-0.53 | 8.11(0.80) | 41.49(0.11) | 2.31(0.26) | 3.30 | 0.62 | 70.77 | 3.4 | 25.6
| 30.06(3.20) | 43.34(0.03) | 0.91(0.04) | 31.03 |  |  |  |
| 26.75(3.24) | 44.20(0.10) | 1.29(0.14) | 19.40 |  |  |  |
| 1.37(0.47) | 45.45(0.03) | 0.37(0.09) | 3.49 |  |  |  |
| 3.32(0.54) | 46.23(0.08) | 1.03(0.20) | 3.04 |  |  |  |
| 1.16(0.26) | 47.77(0.07) | 0.64(0.17) | 1.71 |  |  |  |
G22.04+0.22 | 20.41(1.87) | 50.61(0.04) | 1.04(0.06) | 15.63 | 0.75 | 57.90 | 3.7 | 24.8
| 13.29(1.60) | 51.57(0.01) | 0.51(0.04) | 20.96 |  |  |  |
| 7.07(1.82) | 52.33(0.04) | 1.29(0.04) | 4.36 |  |  |  |
| 4.10(1.14) | 54.03(0.10) | 0.85(0.17) | 3.86 |  |  |  |
| 13.03(2.12) | 55.63(0.72) | 7.40(0.97) | 1.41 |  |  |  |
G23.82+0.38 | 7.25(0.70) | 73.35(0.19) | 3.99(0.41) | 1.71 | 0.58 | 9.67 | 4.6 | 6.4
| 2.43(0.35) | 75.36(0.03) | 0.67(0.08) | 3.41 |  |  |  |
G23.96-0.11 | 0.85(0.29) | 70.82(0.13) | 0.79(0.33) | 1.01 | 0.54 | 9.11 | 4.5 | 5.8
| 0.73(0.28) | 71.83(0.10) | 0.60(0.27) | 1.14 |  |  |  |
| 5.91(0.47) | 73.05(0.02) | 0.81(0.06) | 6.85 |  |  |  |
| 1.62(0.49) | 74.30(0.17) | 1.21(0.41) | 1.26 |  |  |  |
G24.00-0.10 | 1.26(0.61) | 69.28(0.18) | 0.99(0.40) | 1.21 | 0.58 | 3.42 | 4.4 | 2.1
| 2.16(0.73) | 71.05(0.30) | 1.89(0.76) | 1.07 |  |  |  |
G24.11-0.17 | 3.43(0.66) | 82.05(0.26) | 2.73(0.60) | 1.18 | 0.64 | 3.43 | 4.9 | 2.6
G24.33+0.14 | 24.13(0.71) | 113.32(0.00) | 0.67(0.01) | 33.67 | 0.66 | 95.70 | 6.2 | 115.3
| 63.13(0.89) | 114.04(0.02) | 2.23(0.03) | 26.63 |  |  |  |
| 8.45(0.51) | 116.32(0.03) | 1.06(0.06) | 7.47 |  |  |  |
G24.63+0.15 | 1.49(0.26) | 50.89(0.05) | 0.60(0.11) | 2.32 | 0.54 | 3.93 | 3.5 | 1.5
| 0.69(0.30) | 51.95(0.03) | 0.31(0.11) | 2.05 |  |  |  |
| 1.76(0.58) | 52.75(0.27) | 1.64(0.57) | 1.01 |  |  |  |
G24.94+0.07 | 1.50(0.64) | 40.55(0.12) | 0.71(0.20) | 2.00 | 0.46 | 7.66 | 3.0 | 2.2
| 3.73(0.94) | 41.50(0.06) | 0.96(0.25) | 3.66 |  |  |  |
| 0.52(0.29) | 42.25(0.04) | 0.29(0.12) | 1.67 |  |  |  |
| 1.90(0.52) | 43.18(0.22) | 1.66(0.53) | 1.08 |  |  |  |
G25.27-0.43 | 0.98(0.32) | 58.85(0.06) | 0.54(0.14) | 1.71 | 0.47 | 6.73 | 3.9 | 3.2
| 5.40(0.45) | 59.87(0.03) | 1.09(0.12) | 4.67 |  |  |  |
| 0.35(0.17) | 60.77(0.04) | 0.26(0.11) | 1.29 |  |  |  |
G25.38-0.15 | 2.74(0.41) | 93.68(0.02) | 0.60(0.07) | 4.27 | 0.48 | 14.64 | 5.4 | 13.4
| 6.40(0.99) | 94.67(0.23) | 2.39(0.35) | 2.51 |  |  |  |
| 0.22(0.10) | 95.06(0.06) | 0.24(0.18) | 0.88 |  |  |  |
| 0.45(0.19) | 95.74(0.05) | 0.29(0.16) | 1.47 |  |  |  |
| 0.83(0.45) | 96.22(0.06) | 0.35(0.15) | 2.21 |  |  |  |
| 1.33(0.25) | 96.74(0.06) | 0.47(0.25) | 2.67 |  |  |  |
| 0.80(0.33) | 97.29(0.12) | 0.46(0.23) | 1.65 |  |  |  |
| 1.86(0.41) | 99.01(0.22) | 2.12(0.57) | 0.83 |  |  |  |
G27.97-0.47 | 5.10(0.44) | 45.14(0.06) | 1.61(0.13) | 2.98 | 0.49 | 6.83 | 3.1 | 2.1
| 1.73(0.34) | 45.42(0.02) | 0.42(0.06) | 3.87 |  |  |  |
G34.26+0.15 | 35.17(1.77) | 58.04(0.06) | 2.52(0.12) | 13.13 | 0.73 | 64.20 | 3.9 | 30.6
| 1.25(0.28) | 58.89(0.09) | 0.39(0.18) | 2.99 |  |  |  |
| 4.25(1.90) | 59.40(0.06) | 0.62(0.24) | 6.46 |  |  |  |
| 9.89(1.98) | 60.31(0.03) | 0.80(0.16) | 11.56 |  |  |  |
| 8.27(1.20) | 60.96(0.01) | 0.41(0.03) | 18.84 |  |  |  |
| 2.14(0.66) | 61.61(0.08) | 0.66(0.20) | 3.06 |  |  |  |
| 3.23(0.68) | 63.50(0.23) | 2.29(0.59) | 1.32 |  |  |  |
G34.28+0.18 | 3.40(0.54) | 54.84(0.09) | 1.21(0.20) | 2.64 | 0.48 | 24.72 | 3.6 | 10.0
| 11.43(0.50) | 55.75(0.01) | 0.55(0.02) | 19.50 |  |  |  |
| 8.22(0.27) | 56.48(0.01) | 0.42(0.01) | 18.35 |  |  |  |
| 1.68(0.25) | 57.16(0.04) | 0.60(0.11) | 2.63 |  |  |  |
G34.39+0.22 | 6.54(2.51) | 57.15(0.33) | 2.26(0.81) | 2.72 | 0.48 | 11.95 | 3.7 | 5.1
| 1.87(0.95) | 58.28(0.06) | 0.81(0.28) | 2.15 |  |  |  |
| 3.55(0.73) | 60.00(0.15) | 1.61(0.26) | 2.06 |  |  |  |
G34.41+0.24 | 3.90(1.18) | 55.89(0.13) | 1.38(0.23) | 2.66 | 0.49 | 43.05 | 3.7 | 18.5
| 13.09(1.65) | 57.78(0.06) | 2.03(0.27) | 6.06 |  |  |  |
| 1.85(0.69) | 59.49(0.07) | 0.87(0.20) | 1.99 |  |  |  |
| 24.22(1.26) | 58.18(0.16) | 8.77(0.46) | 2.59 |  |  |  |
G35.04-0.47 | 0.54(0.18) | 50.81(0.05) | 0.36(0.12) | 1.43 | 0.47 | 4.27 | 3.4 | 1.5
| 1.95(0.31) | 51.54(0.04) | 0.64(0.11) | 2.84 |  |  |  |
| 1.13(0.54) | 52.77(0.17) | 1.04(0.60) | 1.02 |  |  |  |
| 0.65(0.38) | 53.74(0.12) | 0.57(0.25) | 1.07 |  |  |  |
G35.13-0.74 | 19.70(1.22) | 33.81(0.16) | 5.93(0.30) | 3.12 | 0.53 | 38.11 | 2.5 | 7.5
| 2.94(0.57) | 33.41(0.04) | 0.57(0.08) | 4.80 |  |  |  |
| 4.25(1.53) | 34.39(0.10) | 0.94(0.35) | 4.25 |  |  |  |
| 1.99(0.71) | 35.00(0.03) | 0.41(0.10) | 4.60 |  |  |  |
| 5.40(0.84) | 35.64(0.03) | 0.77(0.13) | 6.58 |  |  |  |
| 3.83(0.49) | 36.59(0.03) | 0.65(0.07) | 5.55 |  |  |  |
G35.20-0.74 | 5.18(0.98) | 32.15(0.17) | 1.87(0.35) | 2.60 | 0.58 | 41.65 | 2.5 | 8.2
| 11.18(1.93) | 33.90(0.06) | 1.24(0.14) | 8.49 |  |  |  |
| 1.96(0.38) | 34.87(0.01) | 0.30(0.04) | 6.17 |  |  |  |
| 23.33(1.73) | 35.37(0.05) | 1.47(0.08) | 14.90 |  |  |  |
G35.79-0.17 | 1.43(0.36) | 59.92(0.02) | 0.36(0.07) | 3.73 | 0.66 | 19.21 | 3.9 | 9.2
| 1.34(0.79) | 60.87(0.08) | 0.66(0.23) | 1.91 |  |  |  |
| 3.17(1.55) | 62.16(0.09) | 1.18(0.30) | 2.53 |  |  |  |
| 12.48(2.32) | 61.52(0.20) | 4.33(0.70) | 2.71 |  |  |  |
| 0.79(0.41) | 64.65(0.11) | 0.66(0.30) | 1.12 |  |  |  |
G39.10+0.49 | 1.10(0.24) | 21.59(0.04) | 0.47(0.10) | 2.21 | 0.58 | 17.26 | 2.0 | 2.2
| 5.47(0.82) | 23.12(0.37) | 4.67(0.82) | 1.10 |  |  |  |
| 10.69(0.47) | 26.31(0.01) | 1.02(0.04) | 9.80 |  |  |  |
G39.39-0.14 | 2.15(0.59) | 65.62(0.31) | 2.23(0.56) | 0.91 | 0.57 | 3.90 | 4.5 | 2.5
| 0.66(0.46) | 65.97(0.11) | 0.38(0.23) | 1.61 |  |  |  |
| 1.09(0.45) | 66.42(0.06) | 0.38(0.13) | 2.71 |  |  |  |
G40.28-0.22 | 30.10(0.54) | 72.77(0.00) | 0.53(0.01) | 53.21 | 0.48 | 124.20 | 5.3 | 109.4
| 79.45(0.66) | 73.31(0.01) | 1.57(0.01) | 47.61 |  |  |  |
| 14.64(0.29) | 75.27(0.01) | 0.93(0.02) | 14.84 |  |  |  |
G40.60-0.72 | 1.37(0.43) | 62.98(0.04) | 0.55(0.12) | 2.32 | 0.49 | 20.37 | 4.5 | 12.9
| 8.97(1.06) | 64.21(0.02) | 0.97(0.06) | 8.72 |  |  |  |
| 10.03(1.41) | 64.52(0.15) | 2.91(0.23) | 3.24 |  |  |  |
G45.80-0.36 | 8.22(0.41) | 58.06(0.06) | 2.45(0.15) | 3.15 | 0.48 | 9.89 | 4.8 | 7.1
| 0.47(0.17) | 59.96(0.05) | 0.33(0.12) | 1.34 |  |  |  |
| 1.20(0.21) | 60.85(0.05) | 0.67(0.13) | 1.67 |  |  |  |
G49.07-0.33 | 1.72(0.23) | 61.43(0.06) | 0.86(0.13) | 1.88 | 0.51 | 2.93 | 5.0 | 2.3
| 1.21(0.25) | 69.50(0.10) | 1.02(0.24) | 1.12 |  |  |  |
G54.45+1.01 | 2.04(0.41) | 36.90(0.06) | 0.61(0.13) | 3.13 | 0.64 | 3.20 | 4.0 | 1.6
| 1.17(0.37) | 39.13(0.09) | 0.50(0.15) | 2.17 |  |  |  |
G59.79+0.63 | 1.66(0.31) | 27.62(0.06) | 0.66(0.14) | 2.37 | 0.76 | 29.35 | 4.0 | 14.7
| 11.31(0.36) | 30.89(0.01) | 0.55(0.02) | 19.29 |  |  |  |
| 16.38(1.01) | 33.53(0.16) | 5.33(0.37) | 2.89 |  |  |  |
G305.48-0.10 | 6.28(0.57) | -38.23(0.11) | 2.53(0.27) | 2.33 | 0.72 | 7.05 | 4.6 | 4.7
| 0.77(0.20) | -35.86(0.03) | 0.28(0.08) | 2.58 |  |  |  |
G305.52+0.76 | 1.50(0.46) | -29.91(0.13) | 1.01(0.29) | 1.40 | 0.61 | 6.04 | 2.8 | 1.5
| 4.54(0.55) | -28.09(0.10) | 1.79(0.26) | 2.38 |  |  |  |
G305.80-0.24 | 4.65(1.02) | -34.21(0.21) | 2.00(0.46) | 2.18 | 0.69 | 13.56 | 3.2 | 4.4
| 4.40(1.48) | -32.17(0.12) | 1.37(0.44) | 3.02 |  |  |  |
| 1.29(0.90) | -31.01(0.13) | 0.71(0.35) | 1.71 |  |  |  |
| 0.97(0.28) | -30.24(0.04) | 0.34(0.10) | 2.68 |  |  |  |
| 2.25(0.51) | -28.32(0.21) | 1.98(0.53) | 1.07 |  |  |  |
G305.82-0.11 | 0.62(0.29) | -44.34(0.17) | 0.79(0.40) | 0.74 | 0.62 | 11.17 | 4.4 | 6.8
| 7.69(1.09) | -41.12(0.19) | 2.79(0.42) | 2.59 |  |  |  |
| 2.48(0.77) | -39.51(0.05) | 0.84(0.17) | 2.77 |  |  |  |
| 0.38(0.18) | -38.69(0.05) | 0.23(0.11) | 1.52 |  |  |  |
G305.89+0.02 | 7.56(0.87) | -34.93(0.07) | 1.23(0.13) | 5.78 | 0.59 | 16.89 | 3.4 | 6.1
| 7.07(0.93) | -33.70(0.04) | 0.96(0.11) | 6.94 |  |  |  |
| 1.11(0.30) | -32.63(0.06) | 0.52(0.14) | 2.00 |  |  |  |
| 1.14(0.22) | -31.47(0.05) | 0.57(0.13) | 1.90 |  |  |  |
G309.91+0.32 | 22.81(0.65) | -61.20(0.01) | 0.64(0.02) | 33.63 | 0.72 | 31.81 | 5.0 | 24.9
| 3.74(0.78) | -60.43(0.05) | 0.68(0.13) | 5.20 |  |  |  |
| 5.26(0.49) | -59.14(0.05) | 1.17(0.13) | 4.22 |  |  |  |
G310.15+0.76 | 1.04(0.23) | -58.42(0.04) | 0.40(0.10) | 2.42 | 0.62 | 19.45 | 5.0 | 15.2
| 3.44(0.29) | -57.61(0.03) | 0.67(0.07) | 4.82 |  |  |  |
| 2.71(0.29) | -56.47(0.02) | 0.51(0.05) | 5.02 |  |  |  |
| 8.93(0.50) | -55.33(0.02) | 1.08(0.07) | 7.74 |  |  |  |
| 3.34(0.49) | -53.42(0.11) | 1.59(0.28) | 1.97 |  |  |  |
G310.38-0.30 | 0.83(0.22) | -55.09(0.07) | 0.52(0.17) | 1.50 | 0.56 | 8.41 | 5.2 | 7.1
| 4.03(0.39) | -54.33(0.01) | 0.41(0.03) | 9.22 |  |  |  |
| 3.55(0.45) | -53.55(0.06) | 0.96(0.14) | 3.46 |  |  |  |
G311.04+0.69 | 0.90(0.15) | 24.66(0.03) | 0.38(0.07) | 2.21 | 0.50 | 0.90 | 12.7 | 4.5
G311.51-0.45 | 2.98(0.70) | -50.91(0.21) | 1.88(0.50) | 1.49 | 0.61 | 2.98 | 4.6 | 2.0
G313.76-0.86 | 7.49(0.85) | -50.55(0.01) | 0.54(0.04) | 12.94 | 0.70 | 36.28 | 4.0 | 18.2
| 8.81(2.01) | -49.78(0.11) | 1.67(0.24) | 4.95 |  |  |  |
| 17.59(1.78) | -49.80(0.21) | 6.70(0.64) | 2.47 |  |  |  |
| 0.51(0.22) | -47.45(0.04) | 0.25(0.11) | 1.91 |  |  |  |
| 1.88(0.26) | -46.69(0.02) | 0.36(0.05) | 4.84 |  |  |  |
G317.87-0.15 | 2.09(0.63) | -42.36(0.14) | 1.27(0.38) | 1.55 | 0.64 | 15.75 | 3.0 | 4.4
| 0.95(0.32) | -41.40(0.03) | 0.34(0.09) | 2.65 |  |  |  |
| 2.60(0.72) | -40.19(0.13) | 1.50(0.38) | 1.63 |  |  |  |
| 10.11(1.33) | -39.80(0.58) | 9.88(1.42) | 0.96 |  |  |  |
G317.88-0.25 | 1.63(0.39) | -38.63(0.10) | 0.87(0.24) | 1.76 | 0.50 | 13.15 | 2.6 | 2.8
| 0.81(0.41) | -37.86(0.06) | 0.44(0.16) | 1.73 |  |  |  |
| 5.29(0.49) | -36.88(0.03) | 1.00(0.11) | 4.96 |  |  |  |
| 5.41(0.39) | -35.53(0.03) | 0.98(0.08) | 5.17 |  |  |  |
G320.23-0.28 | 0.52(0.23) | -67.28(0.05) | 0.32(0.14) | 1.52 | 0.62 | 7.61 | 4.6 | 5.0
| 1.49(0.28) | -66.03(0.02) | 0.36(0.06) | 3.91 |  |  |  |
| 5.15(0.65) | -65.60(0.14) | 2.40(0.36) | 2.02 |  |  |  |
| 0.45(0.20) | -63.78(0.05) | 0.29(0.13) | 1.48 |  |  |  |
G321.94-0.01 | 0.86(0.33) | -35.35(0.03) | 0.26(0.09) | 3.14 | 0.85 | 35.35 | 2.4 | 6.4
| 9.07(1.53) | -34.19(0.10) | 1.52(0.28) | 5.62 |  |  |  |
| 0.94(0.34) | -33.37(0.05) | 0.35(0.16) | 2.52 |  |  |  |
| 19.05(2.20) | -32.41(0.03) | 1.24(0.08) | 14.42 |  |  |  |
| 5.43(2.50) | -30.50(0.77) | 3.40(1.44) | 1.50 |  |  |  |