J/ApJS/206/9 New EGOs from Spitzer GLIMPSE II survey. I. (Chen+, 2013)
Newly identified extended green objects (EGOs) from the Spitzer GLIMPSE II
survey.
I. Catalog.
Chen X., Gan C.-G., Ellingsen S.P., He J.-H., Shen Z.-Q., Titmarsh A.
<Astrophys. J. Suppl. Ser., 206, 9 (2013)>
=2013ApJS..206....9C 2013ApJS..206....9C
ADC_Keywords: Photometry, infrared ; Radio lines ; YSOs ; Interstellar medium
Keywords: infrared: ISM - ISM: jets and outflows - radio lines: ISM -
stars: formation
Abstract:
We have produced a catalog containing 98 newly identified massive
young stellar object (MYSO) candidates associated with ongoing
outflows (known as extended green objects, or EGOs). These have been
identified from the Spitzer Galactic Legacy Infrared Mid-Plane Survey
Extraordinaire (GLIMPSE) II data set and our new identifications
increase the number of known EGOs to ∼400 in our Galaxy, adding to the
∼300 previously identified EGOs reported by Cyganowski et al. (2008,
Cat. J/AJ/136/2391) from the GLIMPSE I survey. The high detection rate
(∼70%) of 95 GHz class I methanol masers achieved in a survey toward
57 of these new EGOs with the Mopra 22m radio telescope demonstrates
that the new EGOs are associated with outflows. Investigations of the
mid-infrared properties and physical associations with other star
formation tracers (e.g., infrared dark clouds, class I and II methanol
masers, and millimeter Bolocam Galactic Plane Survey sources) reveal
that the newly identified EGOs are very similar in nature to those in
the sample of Cyganowski et al. All of the observational evidence
supports the hypothesis that EGOs correspond to MYSOs at the earliest
evolutionary stage, with ongoing outflow activity, and active rapid
accretion.
Description:
We have adopted methods similar to those used by Cyganowski et al.
(2008, Cat. J/AJ/136/2391) to compile a catalog of EGOs in the GLIMPSE
II survey region. We displayed the archived GLIMPSE II Image Atlas
mosaics (Version 3.5). We have constructed images in each of the IRAC
bands (3.6, 4.5, 5.8, and 8.0um), as well as for the Spitzer Multiband
Imaging Photometer (MIPS) 24um band (from the MIPS Galactic Plane
Survey (MIPSGAL survey; Carey et al. 2009PASP..121...76C 2009PASP..121...76C), and a
three-color composite (3.6um-blue, 4.5um-green, and 8.0-m-red) for
each of the 98 newly identified EGOs.
To investigate the nature of the newly cataloged EGO sample from the
GLIMPSE II survey region, we have performed a survey for molecular
lines in the 3mm band toward ∼60% of the sources with the ATNF Mopra
22m radio telescope. The Mopra observations consisted of a single
pointing for each source and were undertaken in the period 2009 August
9-20.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 128 98 Mid-IR integrated flux densities of newly
identified EGOs in the region -10°<l<10°
table2.dat 53 98 Infrared point source associations of EGOs
table3.dat 73 90 Observed properties of 95GHz class I methanol
maser sources detected
table4.dat 25 98 Associations of the newly identified EGOs with
other star formation tracers
table5.dat 70 63 Parameters of the 1.1mm Bolocam GHz peak sources
(BGPS) associated with EGOs
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See also:
II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)
J/ApJS/206/22 : Newly EGOs from GLIMPSE II survey. II. MoC (Chen+, 2013)
J/ApJS/202/1 : 1mm spectral line survey toward GLIMPSE EGOs (He+, 2012)
J/ApJS/196/9 : 95GHz methanol maser survey toward GLIMPSE EGOs (Chen+, 2011)
J/ApJ/736/133 : Spitzer study of massive YSOs in galactic center (An+, 2011)
J/ApJS/188/123 : The Bolocam Galactic Plane Survey. II. (Rosolowsky+, 2010)
J/ApJ/710/150 : Molecular lines in EGOs (Chen+, 2010)
J/A+A/505/405 : A catalogue of Spitzer dark clouds (Peretto+, 2009)
J/ApJ/702/1615 : CH3OH maser survey of EGOs (Cyganowski+, 2009)
J/AJ/136/2391 : GLIMPSE Extended Green Objects catalog (Cyganowski+, 2008)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq [1/98] Running sequence number
4- 18 A15 --- EGO EGO name (GLLL.ll+B.bb(a))
20- 21 I2 h RAh [17/18] Hour of right ascension (J2000) (1)
23- 24 I2 min RAm Minute of right ascension (J2000)
26- 29 F4.1 s RAs Second of right ascension (J2000)
31 A1 --- DE- [-] Sign of declination (J2000) (1)
32- 33 I2 deg DEd [20/38] Degree of declination (J2000) (1)
35- 36 I2 arcmin DEm Arcminute of declination (J2000)
38- 39 I2 arcsec DEs Arcsecond of declination (J2000)
41- 44 F4.1 kpc Dist [0/12.1]? Kinematic distance (2)
46- 50 A5 --- f_Dist [ *,adf] Flag(s) on Dist (3)
52- 55 I4 arcsec2 Area [36/3622] Area over which the IRAC
flux densities were integrated
57- 59 I3 arcsec2 Area24 [0/731]? Area over which the 24um MIPS
flux densities were integrated
61- 66 F6.1 mJy [3.6] [1/1434] Spitzer/IRAC Integrated flux
density at 3.6um
68- 71 F4.1 mJy e_[3.6] [0.6/59] [3.6] uncertainty
73- 78 F6.1 mJy [4.5] [5.7/4101.6] Spitzer/IRAC Integrated flux
density at 4.5um
80- 83 F4.1 mJy e_[4.5] [0.7/52.8] [4.5] uncertainty
85- 91 F7.2 mJy [5.8] [4.1/7861.6] Spitzer/IRAC Integrated flux
density at 5.8um
93- 97 F5.1 mJy e_[5.8] [1.2/415.6] [5.8] uncertainty
99-104 F6.1 mJy [8.0] [0/8920.5]? Spitzer/IRAC Integrated flux
density at 8um
106-110 F5.1 mJy e_[8.0] [1/413]? [8.0] uncertainty
112-117 F6.1 mJy [24] [0/7064.8]? Spitzer/MIPS integrated flux
density at 24um
119-123 F5.1 mJy e_[24] [2.8/141.3]? [24] uncertainty
125-126 A2 --- f_[24] [ msnc] reason of missing [24] (4)
128 A1 --- 3mm [Y ] Included in the 3mm line survey? (5)
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Note (1): Position (RA and DEC, respectively) of the brightest 4.5um emission
associated with the EGO.
Note (2): The kinematic distance to the source estimated from the galactic
rotation curve of Reid et al. (2009ApJ...700..137R 2009ApJ...700..137R)
Note (3): Flags as follows (blank values are sources with no velocity
information):
* = Velocity information taken from the Mopra observations and 6.7GHz
class II methanol maser data from Caswell et al. (2010MNRAS.404.1029C 2010MNRAS.404.1029C)
and Green et al. (2010MNRAS.409..913G 2010MNRAS.409..913G)
d = The distances to sources which cannot be derived from the Galactic
rotation curve are assumed to be 3.0kpc, except for G359.61-0.24 which
was assumed to be at 7.0kpc.
a = sources that are located in the 3 kpc arms (see section 4.2).
f = We adopt the near kinematic distance for all of sources except
G2.14+0.01, G350.36-0.07, G351.69+0.17 and G353.46+0.56, for which far
kinematic distances were adopted.
Note (4): Flux densities in the 24um MIPS band were not estimated for sources
with flag as follows:
c = there is confusion due to background
s = saturation
nc = no counterpart emission
n = no data
m = multiple MIPS sources are close together within or nearby the IRAC
aperture; for these sources only a lower limit for the 24um flux density
is given (see Section 2.1).
Note (5): "Y": the source was included in the 3mm line survey undertaken
with Mopra (see Section 3.1).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- EGO EGO name (GLLL.ll+B.bb(a))
17- 26 A10 --- IRAS Nearest IRAS-PSC source name (B1950 coordinates)
28- 30 I3 arcsec ISep [1/456] Nearest IRAS point source separation
32- 48 A17 --- MSX6C Nearest MSX source name
50- 53 I4 arcsec MSep [1/132] Nearest MSX point source separation
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- EGO EGO name (GLLL.ll+B.bb)
15 A1 --- f_EGO [a] Multiple EGOs (1)
17- 22 F6.2 km/s V [-96/159] Local Standard of Rest maser velocity
24- 27 F4.2 km/s e_V Formal error from Gaussian fit in V
29- 32 F4.2 km/s dV [0.1/8.7] Full-Width at Half-Maximum line width
34- 37 F4.2 km/s e_dV Formal error from Gaussian fit in dV
39- 42 F4.2 K.km/s I [0.05/5.4] Integrated maser intensity
44- 47 F4.2 K.km/s e_I Formal error from Gaussian fit in I
49- 52 F4.2 K P [0.06/6.31] Main beam temperature
54- 57 F4.1 Jy.km/s S [0.5/76.1]? Total integrated flux density (2)
59- 61 F3.1 Jy.km/s e_S ? Formal error from Gaussian fit in S
63- 67 F5.1 10-6Lsun Lm [0.1/300]? Integrated luminosity (3)
69- 73 F5.2 10-6Lsun e_Lm ? Formal error from Gaussian fit in Lm
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Note (1): a = Multiple EGOs were observed simultaneously in the same Mopra
beam. G358.46-0.39 included the two EGOs G358.46-0.39(a) and
G358.46-0.39(b).
Note (2): Of the maser spectrum obtained from summing the integrated flux
density of all maser features. The corresponding values in flux
density can be obtained by multiplying main beam temperature by
a factor of 9.3.
Note (3): Of 95GHz methanol maser estimated assuming isotropic emission from
the maser, i.e. Lm=4*pi*D2*S.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- EGO EGO name (GLLL.ll+B.bb(a))
17 A1 --- IRDC [Y/N] Association with an infrared dark cloud? (6)
19 A1 --- IImas [Y/N] Association with a 6.7GHz methanol maser? (7)
21 A1 --- Imas [YN-] Association with a class I methanol
maser? (-: no information) (8)
23 A1 --- f_Imas [d] d: from literature
25 A1 --- BGPS [YN-] Association with a 1.1mm continuum
BOLOCAM GPS (BGPS) source? (-: no information) (9)
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Note (6): The clear high-resolution Spitzer IRAC 8.0um images provide a
good data set for investigating whether there are associations between
our newly identified EGOs and IRDCs. One point to note is that for the
GLIMPSE II data set we can only identify IRDCs by visual examination,
as opposed to cross-matching with an independent catalog, as at
present there is no equivalent of the GLIMPSE I Spitzer IRDC catalog
of Peretto & Fuller (2009, Cat. J/A+A/505/405). A visual inspection of
the GLIMPSE 8um images was performed for each of our cataloged EGOs to
identify those which are within IRDC environments. We found 61%
(60/98) of the EGOs are embedded within IRDCs, an association rate
that is consistent with that of 67% determined by Cyganowski et al.
(2008, Cat. J/AJ/136/2391) for their EGO sample.
Note (7): From the 6.7GHz class II maser catalogs (Caswell et al.
2010MNRAS.404.1029C 2010MNRAS.404.1029C; Green et al. 2010MNRAS.404.1029C 2010MNRAS.404.1029C); 36
associations for 98 sources in the sample.
Note (8): Class I methanol maser data from our Mopra survey unless flagged.
(45/62 associations)
Note (9): From 1.1mm BGPS archive (Rosolowsky et al. 2010, J/ApJS/188/123);
63/67 associations.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- EGO EGO name
17- 20 I4 --- BGPS [663/8353] BGPS ID number
22- 25 F4.1 arcsec Rad [17/97] Radius
27- 31 F5.2 Jy Sv40 [0.1/21] Flux density with 40" aperture (1)
33- 36 F4.2 Jy e_Sv40 Uncertainty in Sv40
38- 42 F5.2 Jy Svint [0.24/38] Integrated flux density with BGPS
source radius (1)
44- 47 F4.2 Jy e_Svint Uncertainty in Svint
49- 53 I5 Msun Mass [9/14000]? Gas mass (2)
55- 58 F4.1 10+22cm-2 NH2 [0.3/60.8]? Average H2 column density (2)
60- 63 F4.1 10+22cm-2 NH2b [0.3/73.1]? Beam-averaged H2 column density (2)
65- 70 F6.1 10+3cm-3 nH2 [0.8/1664.4]? Average H2 volume density (2)
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Note (1): Directly extracted (without any corrections) from
Rosolowsky et al. (BGPS; 2010, Cat. J/ApJS/188/123).
Note (2): Values are left blank for the sources for which distances were not
determined in our work (see Section 4.2.5).
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History:
From electronic version of the journal
References:
Chen et al. Paper II. 2013ApJS..206...22C 2013ApJS..206...22C Cat. J/ApJS/206/22
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 14-Oct-2013