J/ApJ/764/61 Water maser and NH3 survey of GLIMPSE EGOs (Cyganowski+, 2013)
A water maser and NH3 survey of GLIMPSE extended green objects.
Cyganowski C.J., Koda J., Rosolowsky E., Towers S., Meyer J.D., Egusa F.,
Momose R., Robitaille T.P.
<Astrophys. J., 764, 61 (2013)>
=2013ApJ...764...61C 2013ApJ...764...61C
ADC_Keywords: Infrared sources ; Radio lines ; Masers ; YSOs ; Surveys ;
Interstellar medium
Keywords: infrared: ISM; ISM: jets and outflows; ISM: molecules; masers;
stars: formation
Abstract:
We present the results of a Nobeyama 45m H2O maser and NH3 survey
of all 94 northern GLIMPSE extended green objects (EGOs), a sample of
massive young stellar objects (MYSOs) identified based on their
extended 4.5µm emission. We observed the NH3(1,1), (2,2), and
(3,3) inversion lines, and detected emission toward 97%, 63%, and 46%
of our sample, respectively (median rms∼50mK). The H2O maser
detection rate is 68% (median rms∼0.11Jy). The derived H2O maser and
clump-scale gas properties are consistent with the identification of
EGOs as young MYSOs. To explore the degree of variation among EGOs, we
analyze subsamples defined based on mid-infrared (MIR) properties or
maser associations. H2O masers and warm dense gas, as indicated by
emission in the higher-excitation NH3 transitions, are most
frequently detected toward EGOs also associated with both
Class I and II CH3OH masers. Ninety-five percent (81%) of such EGOs
are detected in H2O (NH3(3,3)), compared to only 33% (7%) of EGOs
without either CH3OH maser type. As populations, EGOs associated
with Class I and/or II CH3OH masers have significantly higher NH3
line widths, column densities, and kinetic temperatures than EGOs
undetected in CH3OH maser surveys. However, we find no evidence for
statistically significant differences in H2O maser properties (such
as maser luminosity) among any EGO subsamples. Combining our data with
the 1.1mm continuum Bolocam Galactic Plane Survey, we find no
correlation between isotropic H2O maser luminosity and clump number
density. H2O maser luminosity is weakly correlated with clump (gas)
temperature and clump mass.
Description:
We targeted all 94 EGOs in the Cyganowski+ 2008 catalog
(J/AJ/136/2391) visible from Nobeyama (those in the northern Galactic
plane, DEC≳-20°). The NH3(J,K)=(1,1), (2,2), and (3,3)
inversion transitions and the 22.235GHz H2O maser line were observed
simultaneously with the Nobeyama Radio Observatory 45m telescope
(NRO45) in 2008-2010.
We used the H22 receiver, a cooled HEMT receiver, and eight
high-resolution acousto-optic spectrometers (AOSs) to observe both
polarizations for each line simultaneously. The bandwidth and spectral
resolution of the AOSs are 40MHz and 37kHz, respectively,
corresponding to velocity coverage of ∼500km/s and resolution of
∼0.5km/s for the observed lines.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 43 94 EGO sample: properties from the literature
table3.dat 152 94 NH3 properties: single component fits
table4.dat 65 42 NH3 properties: two component fits
table6.dat 84 64 H2O maser properties: detections
table8.dat 105 77 Properties of associated BGPS dust clumps
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See also:
J/A+A/563/A130 : GLIMPSE/BGPS 6.7GHz methanol maser survey (Sun+, 2014)
J/ApJS/206/22 : Newly EGOs from GLIMPSE II survey. II. MoC (Chen+, 2013)
J/ApJS/206/9 : New EGOs from Spitzer GLIMPSE II survey. I. (Chen+, 2013)
J/ApJS/202/1 : 1mm spectral line survey toward GLIMPSE EGOs (He+, 2012)
J/ApJ/753/50 : 6.7GHz methanol masers. I. NH3 lines (Pandian+, 2012)
J/MNRAS/418/1689 : Red MSX water maser and ammonia emissions (Urquhart+, 2011)
J/MNRAS/416/1764 : H2O Southern Galactic Plane Survey (HOPS) (Walsh+, 2011)
J/MNRAS/416/178 : 1.2-mm dust clumps with luminous water masers (Breen+, 2011)
J/ApJS/196/9 : 95GHz methanol maser survey of GLIMPSE EGOs (Chen+, 2011)
J/ApJ/741/110 : The BGPS. VII. Massive star-forming regions (Dunham+, 2011)
J/ApJ/731/90 : Mid-IR content of BGPS sources (Dunham+, 2011)
J/ApJS/188/123 : The Bolocam Galactic Plane Survey. II. (Rosolowsky+, 2010)
J/ApJ/723/1019 : Galactic SFR and gas surface densities (Heiderman+, 2010)
J/ApJ/721/137 : The Bolocam Galactic Plane Survey (BGPS) (Bally+, 2010)
J/ApJ/710/150 : Molecular lines in EGOs (Chen+, 2010)
J/A+A/507/795 : The RMS survey: water masers of YSOs (Urquhart+, 2009)
J/ApJ/707/283 : VLA observation of molecular clumps (Johnston+, 2009)
J/ApJ/702/1615 : CH3OH maser survey of EGOs (Cyganowski+, 2009)
J/ApJS/175/509 : Ammonia spectral atlas in Perseus (Rosolowsky+, 2008)
J/AJ/136/2391 : GLIMPSE Extended Green Objects catalog (Cyganowski+, 2008)
J/ApJ/651/L125 : Water masers associated with IRDC cores (Wang+, 2006)
J/ApJ/641/389 : Millimetric observations of IRDC cores (Rathborne+, 2006)
J/A+A/434/613 : H2O maser survey of methanol maser sources (Szymczak+, 2005)
J/MNRAS/363/405 : SIMBA observations of cold cores (Hill+, 2005)
J/ApJS/155/149 : CH3OH 70-61 A+ maser sources (Kurtz+, 2004)
J/A+A/403/1095 : 6.7GHz methanol masers survey of YSOs (Minier+, 2003)
J/A+AS/137/43 : OH/H2O masers database (Forster+, 1999)
J/A+AS/120/283 : Water maser in ultracompact HII regions (Hofner+ 1996)
J/ApJ/463/205 : CS and NH3 Survey of H2O Maser Emission (Anglada+ 1996)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- EGO Source name (GLL.ll+B.bb(a))
16- 17 I2 h RAh Hour of Right Ascension (J2000) (1)
19- 20 I2 min RAm Minute of Right Ascension (J2000)
22- 25 F4.1 s RAs Second of Right Ascension (J2000)
27 A1 --- DE- Sign of the C08 Declination (J2000) (1)
28- 29 I2 deg DEd Degree of Declination (J2000) (1)
31- 32 I2 arcmin DEm Arcminute of Declination (J2000)
34- 35 I2 arcsec DEs Arcsecond of Declination (J2000)
37 I1 --- C08 [1/5] Table number from C08 EGO Catalog (1)
39 A1 --- IRDC? [NY] In the IRDC? (IR dark cloud) (1)
41 A1 --- ClII [NY-] CH3OH class II maser? (2)
43 A1 --- ClI [NY] CH3OH class I maser? (2)
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Note (1): From Cyganowski et al. (2008, J/AJ/136/2391; C08;
in Simbad):
* Tables 1 and 2 of C08 listed "likely" outflow candidates;
* tables 3 and 4 "possible" outflow candidates.
* Table 5 sources are those for which only "outflow-only" photometry
was presented; we do not include them in our analysis of "likely"
and "possible" subsamples.
Note (2): From Chen et al. (2011, J/ApJS/196/9; CE11) (only). EGOs in our
sample that are not included in CE11 are indicated by blanks. A "-"
indicates a source with a single-dish 6.7GHz CH3OH maser detection
but no positional information, considered as having "no information"
at 6.7GHz by CE11 (see Section 3.1.1).
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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- 14 A14 --- EGO Source name
16 A1 --- f_EGO [j] No NH3(2,2) (3)
18- 23 F6.2 km/s VLSR [-4/114]? Local Standard of Rest Velocity
25- 28 F4.2 km/s e_VLSR [0.01/0.2]? Uncertainty in VLSR
30- 33 F4.2 km/s sigma [0.2/2.2]? Gaussian line width
35- 38 F4.2 km/s e_sigma ? Uncertainty in sigma
40- 44 F5.2 kpc Dist [0.5/13] Distance (G2)
46- 49 F4.2 kpc E_Dist Upper uncertainty in Dist
51- 54 F4.2 kpc e_Dist Lower uncertainty in Dist
56- 58 A3 --- n_Dist Note on distance (G1)
60 A1 --- l_Tmb11 The 4σ upper limit flag on Tmb11
61- 65 F5.2 K Tmb11 [0.1/3.1] Peak temperature of NH3(1,1) line
67- 70 F4.2 K e_Tmb11 ? The 1σ rms uncertainty in Tmb11
72- 76 F5.2 --- tau11 ? Optical depth of NH3(1,1) line
78- 81 F4.1 10+14/cm2 N(NH3) [0.1/34]? Column density of NH3
83- 85 F3.1 10+14/cm2 e_N(NH3) ? Uncertainty in N(NH3) (4)
87- 91 F5.3 --- eta [0/1]? Beam filling factor η
93 A1 --- l_eta Limit flag on e_eta
94- 99 F6.3 --- e_eta ? Uncertainty in eta (4)
101-105 F5.2 K Tex ? Excitation temperature
107-110 F4.2 K e_Tex ? Uncertainty in Tex (4)
112 A1 --- l_Tkin Limit flag on Tkin (5)
113-117 F5.2 K Tkin ? Kinetic temperature
119 A1 --- f_Tkin Flag on Tkin (6)
121-124 F4.2 K e_Tkin ? Uncertainty in Tkin (4)
126 A1 --- l_Tmb22 The 4σ upper limit flag on Tmb22
127-131 F5.2 K Tmb22 [0.1/2.3] Peak temperature of NH3(2,2) line
133-136 F4.2 K e_Tmb22 ? The 1σ rms uncertainty in Tmb22
138 A1 --- l_Tmb33 The 4σ upper limit flag on Tmb33
139-143 F5.2 K Tmb33 [0.1/2.1] Peak temperature of NH3(3,3) line
145-148 F4.2 K e_Tmb33 ? The 1σ rms uncertainty in Tmb33
150 A1 --- C2 [NY] Two components? (7)
152 A1 --- H2O [NY] Water maser?
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Note (3):
j = Source that meets 4σ detection criterion for NH3(1,1) and (3,3),
but not (2,2); hence, Tkin is treated as an upper limit as for other
(2,2) nondetections. See also Section 3.2.1.
Note (4): The uncertainties are estimated from the model optimization.
Uncertainties of 0.00 indicate the case Tkin=Tex (see Section 2.2).
Note (5): Tkin is indicated as an upper limit if NH3(2,2) emission is not
detected at >4σ.
Note (6):
l = This temperature limit is likely excessively low because the criteria
of least-squares fitting are failing and the error distributions are
non-Gaussian.
Note (7): Indicates whether a two component model was fit (Section 2.2).
If "Y", the two-component model results are listed in Table 4.
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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- 11 A11 --- EGO Source Name
13- 17 F5.2 K Tkin [4.2/68] Kinetic temperature
19- 23 F5.2 K e_Tkin [0.2/13] Uncertainty in Tkin
25- 30 F6.2 km/s VLSR [12/114] Local Standard of Rest Velocity
32- 35 F4.2 km/s e_VLSR [0.01/0.2] Uncertainty in VLSR
37- 40 F4.2 km/s sigma [0.4/4] Gaussian line width
42- 45 F4.2 km/s e_sigma [0.01/0.3] Uncertainty in sigma
47- 51 F5.2 K Tex [2/62] Excitation temperature
53- 56 F4.2 K e_Tex [0/0.8] Uncertainty in Tex (1)
58- 61 F4.1 10+14/cm2 N(NH3) [1.4/79] Column density of NH3
63- 65 F3.1 10+14/cm2 e_N(NH3) [0.1/10] Uncertainty in N(NH3)
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Note (1): Uncertainties are estimated from the model optimization: values
of 0.00 indicate cases where the model is poorly constrained (see
Section 2.2).
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- EGO Source name
16- 19 F4.2 Jy sigma [0.05/0.2] RMS in observed spectrum
21- 26 F6.1 km/s Vmin [-183/93] Minimum velocity of maser emission
28- 32 F5.1 km/s Vmax [-26/132] Maximum velocity of maser emission
34- 38 F5.1 km/s Vpeak [-29/111] Velocity of peak maser emission
40- 44 F5.1 km/s DelV Range in maser emission velocity
46- 50 F5.1 km/s VNH3 [8/114]? NH3 velocity
52- 56 F5.1 Jy Speak [0.2/812] Peak maser flux density
58- 65 F8.3 Jy.km/s Sint [0.1/2696] Integrated maser flux density
67- 74 E8.2 Lsun Liso Isotropic maser luminosity
76- 84 A9 --- Note Source note (1)
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Note (1): References are for previously reported H2O masers with accurate
positions from interferometric observations that fall within the
polygonal aperture for the EGO published by Cyganowski et al. (2008,
J/AJ/136/2391; see section 3.3). The codes are:
B02 = Beuther et al. (2002A&A...390..289B 2002A&A...390..289B)
B11 = Bartkiewicz et al. (2011A&A...525A.120B 2011A&A...525A.120B).
BE11 = Breen & Ellingsen (2011, J/MNRAS/416/178)
CG11 = Caswell & Green (2011MNRAS.411.2059C 2011MNRAS.411.2059C)
FC99 = Foster & Caswell (1999, J/A+AS/137/43)
HC96 = Hofner & Churchwell (1996, J/A+AS/120/283)
S10 = Sato et al. (2010PASJ...62..287S 2010PASJ...62..287S)
W06 = Wang et al. (2006, J/ApJ/651/L125).
(blank) = indicates no H2O maser reference meeting these criteria was
found in a SIMBAD search.
* = indicates an "Outflow-only" source in Cyganowski et al. (2008,
J/AJ/136/2391). The published polygonal aperture does not include
the "central" source, which is associated with H2O maser emission
(G12.91-0.26: BE11; G34.26+0.15: FC99; G37.55+0.20: B02).
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- EGO Source name
16- 19 I4 --- Bseq [1474/6472] BGPS catalog identifier (1)
21- 24 F4.1 Jy S1.1 [0.3/79] BGPS 1.1mm source flux density (2)
26- 28 F3.1 Jy e_S1.1 [0.1/5] Uncertainty in S1.1
30- 34 F5.2 kpc Dist [0.5/13] Distance (G2)
36- 39 F4.2 kpc E_Dist Upper uncertainty in Dist
41- 44 F4.2 kpc e_Dist Lower uncertainty in Dist
46- 48 A3 --- n_Dist Note on distance (G1)
50- 50 A1 --- l_Rad Limit flag on Rad
51- 55 F5.1 arcsec Rad Angular radius
57 A1 --- l_R Limit flag on PRad
58- 62 F5.2 pc R Physical radius
64 A1 --- l_M(1) Limit flag on M(1) (3)
65- 69 I5 Msun M(1) [6/11740]? Clump mass if single component (3)
71- 74 I4 Msun E_M(1) ? Upper uncertainty in M(1) (3)
76- 79 I4 Msun e_M(1) ? Lower uncertainty in M(1) (3)
81 A1 --- l_nH2(1) Limit flag on nH2(1) (3)
82- 85 F4.1 [cm-3] nH2(1) ? Log H2 density, one component NH3 Tkin (3)
87 A1 --- f_nH2(1) Flag on 1ClognH2 (4)
89- 91 F3.1 [cm-3] E_nH2(1) ? Upper uncertainty in 1ClognH2 (3)
93- 95 F3.1 [cm-3] e_nH2(1) ? Lower uncertainty in 1ClognH2 (3)
97-101 I5 Msun M(2) [361/14275]? Clump mass, two components (5)
103-105 F3.1 [cm-3] nH2(2) ? Log H2 density, 2 component NH3 Tkin (5)
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Note (1): For EGOs matched to a BGPS (Bolocam Galactic Plane Survey) source
but undetected in NH3 emission, the BGPS clump ID and radius are
listed, but no clump mass and density are calculated.
Note (2): Taken directly from the BGPS catalog, Rosolowsky et al. (2010,
J/ApJS/188/123). The recommended correction factor is applied when
calculating clump masses and densities (Section 3.4).
Note (3): Calculated from the integrated flux density in the BGPS catalog
assuming isothermal dust emission and Tdust=Tkin from Table 3.
Quoted ranges include the uncertainties in the integrated flux density
from the BGPS catalog, the recommended BGPS flux correction factor,
and the distance. See also Section 3.4 and Section 4.1.2.
Note (4):
k = The density range is not constrained because the lower end of the
distance range is 0.0kpc.
Note (5): Calculated for sources fit with two NH3 components as described
in Section 3.4. Because the systematic uncertainties in this estimate
are difficult to quantify, only nominal values are listed (which
assume a BGPS correction factor of 1.5 and the nominal integrated flux
from the BGPS catalog).
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Global notes:
Note (G1): Flag as follows:
f = Associated with a 6.7GHz CH3OH maser assigned the far distance by
Green & McClure-Griffths (2011MNRAS.417.2500G 2011MNRAS.417.2500G). Except for G12.20-0.03
and G45.80-0.36, all far distance assignments are "B" classifications in
their scheme (see also Section 3.2.1). We adopt the far kinematic
distance estimated from the NH3 vLSR.
g = The longitude and velocity of this source indicate that it is likely in
the near 3kpc arm (see for example Fig. 1 of Green et al.
(2009ApJ...696L.156G 2009ApJ...696L.156G)).
Following Green & McClure-Griffths (2011MNRAS.417.2500G 2011MNRAS.417.2500G), we place this
source on a circle of radius 3.4kpc around the Galactic Center, and
adopt a distance uncertainty of ±0.2kpc.
h = Maser parallax distance. References:
G14.33-0.64, Sato et al. (2010PASJ...62..287S 2010PASJ...62..287S).
G23.01-0.41, Brunthaler et al. (2009ApJ...693..424B 2009ApJ...693..424B).
G34.39+0.22 and G34.41+0.24, Kurayama et al. (2011PASJ...63..513K 2011PASJ...63..513K).
G35.20-0.74, Zhang et al. (2009ApJ...693..419Z 2009ApJ...693..419Z).
i = It is unclear if this source is at the near or the far distance
(e.g. Cyganowski et al. 2011ApJ...729..124C 2011ApJ...729..124C;
Green & McClure-Griffths 2011MNRAS.417.2500G 2011MNRAS.417.2500G).
j = NH3 nondetection.
G49.42+0.33: distance estimated using H13CO+ velocity from
Cyganowski+, 2009, J/ApJ/702/1615.
G53.92-0.07: distance estimated using H2O maser peak velocity.
G57.61+0.02: distance estimated from velocity of weak (3.9σ)
NH3(1,1) emission below our 4σ detection threshold.
The distance for G57.61+0.02 is included here and in Figure 4 for
completeness, but this source is otherwise excluded from our analysis.
See also Section 3.2.1.
Note (G2): The near kinematic distance, estimated using the NH3 vLSR,
is given except as otherwise noted. For kinematic distances, the
uncertainties are based on the prescription of Reid et al.
(2009ApJ...700..137R 2009ApJ...700..137R); for maser parallax distances, the uncertainties
are taken from the cited reference. See also Section 3.2.1.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 24-Oct-2014