J/ApJ/831/73 Galactic MCs associated with HII regions (Vutisalchavakul+, 2016)
Star formation relations in the Milky Way.
Vutisalchavakul N., Evans II N.J., Heyer M.
<Astrophys. J., 831, 73-73 (2016)>
=2016ApJ...831...73V 2016ApJ...831...73V (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; H II regions ; Radio lines ; Infrared sources ;
Millimetric/submm sources ; Galactic plane ; Velocity dispersion
Keywords: galaxies: star formation; H II regions; stars: formation
Abstract:
The relations between star formation and properties of molecular
clouds (MCs) are studied based on a sample of star-forming regions in
the Galactic Plane. Sources were selected by having radio
recombination lines to provide identification of associated MCs and
dense clumps. Radio continuum emission and mid-infrared emission were
used to determine star formation rates (SFRs), while 13CO and
submillimeter dust continuum emission were used to obtain the masses
of molecular and dense gas, respectively. We test whether total
molecular gas or dense gas provides the best predictor of SFR. We also
test two specific theoretical models, one relying on the molecular
mass divided by the free-fall time, the other using the free-fall time
divided by the crossing time. Neither is supported by the data. The
data are also compared to those from nearby star-forming regions and
extragalactic data. The star formation "efficiency," defined as SFR
divided by mass, spreads over a large range when the mass refers to
molecular gas; the standard deviation of the log of the efficiency
decreases by a factor of three when the mass of relatively dense
molecular gas is used rather than the mass of all of the molecular
gas.
Description:
In this paper, we collect data from surveys of radio recombination
lines (RRLs), radio continuum emission, and MIR emission to measure
SFR, from 13CO spectroscopy to evaluate molecular cloud (MC)
properties, and from millimeter dust continuum emission to trace the
dense gas component. See section 2 for the data sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 52 66 Radio recombination line sources
table2.dat 45 66 Star formation rates
table3.dat 89 66 The 13CO derived molecular properties
table4.dat 59 64 BGPS-derived dense gas properties
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See also:
J/A+A/588/A104 : Molecular clouds and star formation (Gong+, 2016)
J/A+A/588/A29 : Star formation in massive clumps in Milky Way (Heyer+, 2016)
J/ApJ/805/157 : BGPS. XIII. Mass functions (Ellsworth-Bowers+, 2015)
J/ApJ/805/31 : IR-radio luminosities + surface densities of gal. (Liu+, 2015)
J/ApJS/212/1 : The WISE catalog of Galactic HII regions (Anderson+, 2014)
J/ApJ/780/173 : Masses of giant molecular clouds in MW (Battisti+, 2014)
J/ApJS/209/2 : The BGPS. X. Dense molecular gas (Shirley+, 2013)
J/MNRAS/431/1587 : GRS/BGPS sources in Galactic Plane (Eden+, 2013)
J/ApJ/754/62 : HRDS III. HII region kinematic distances (Anderson+, 2012)
J/ApJS/195/14 : The BGPS. V. (Schlingman+, 2011)
J/ApJ/741/110 : The BGPS. VII. Massive star-forming regions (Dunham+, 2011)
J/ApJ/723/1019 : Galactic SFR and gas surface densities (Heiderman+, 2010)
J/ApJ/723/492 : Properties of GRS molecular clouds (Roman-Duval+, 2010)
J/ApJS/188/123 : The Bolocam Galactic Plane Survey. II. (Rosolowsky+, 2010)
J/ApJS/184/1 : Molecular clouds in the LMC by NANTEN. II. (Kawamura+, 2009)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- ID WISE identifier (GLLL.lll+BB.bbb) (G1)
17- 22 F6.3 deg GLON Galactic longitude
24- 29 F6.3 deg GLAT Galactic latitude
31- 35 F5.1 km/s Vel [4/104] Radio recombination line velocity
37- 40 F4.1 kpc Dist [1/14] Distance
42- 44 F3.1 kpc e_Dist [0.1/2] The 1σ uncertainty in Dist
46- 48 F3.1 kpc RGal [4/8] Galactic radius
50 I1 --- r_Vel Reference code for Vel (1)
52 I1 --- r_Dist Reference code for Dist (1)
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Note (1): Reference as follows:
1 = Anderson et al. (2014, J/ApJS/212/1);
2 = Battisti & Heyer (2014, J/ApJ/780/173);
3 = Ellsworth-Bowers et al. (2015, J/ApJ/805/157).
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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 --- ID WISE identifier (GLLL.lll+BB.bbb) (G1)
17- 23 F7.2 Msun/Myr SFR-Rad [0.07/1220] Star Formation Rate from Radio
25- 30 F6.2 Msun/Myr e_SFR-Rad [0.01/122] The 1σ error in SFR-Rad
32- 38 F7.2 Msun/Myr SFR-MIR [0/1112] Star Formation Rate from Mid-IR
40- 45 F6.2 Msun/Myr e_SFR-MIR [0/112] The 1σ error in SFR-MIR
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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- 15 A15 --- ID WISE identifier (GLLL.lll+BB.bbb) (G1)
17 I1 --- Type Type code (2)
19- 23 F5.2 pc rCloud [2/34] Cloud effective radius
25- 28 F4.2 pc e_rCloud [0.01/9] The 1σ error in rCloud
30- 33 F4.2 km/s delv [0.6/4] The 1-dimensional velocity dispersion
35- 38 F4.2 km/s e_delv [0.01/2] The 1σ error in delv
40- 44 F5.1 kMsun MCloud [1/319] Cloud mass
46- 50 F5.1 kMsun e_MCloud [0.5/129] The 1σ error in MCloud
52- 56 F5.1 kMsun MVir [2/275] Cloud virial mass
58- 61 F4.1 kMsun e_MVir [0.3/96] The 1σ error in MVir
63- 66 F4.2 --- alpha [0.02/6] Virial parameter; MVir/MCloud
68- 71 F4.2 --- e_alpha [0.02/3] The 1σ error in alpha
73- 76 I4 cm-3 nCloud [12/8396] Cloud mean volume density
78- 81 I4 cm-3 e_nCloud [7/5985] The 1σ error in nCloud
83- 85 F3.1 Myr tff [0.3/10] Free-fall time
87- 89 F3.1 Myr e_tff [0.2/8] The 1σ error in tff
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Note (2): Code as follows:
1 = the earliest stage of massive star formation (Type II of
Kawamura+, 2009, J/ApJS/184/1)
2 = the initial feedback from massive stars;
3 = a very late stage in which the original cloud has been mostly
photoionized or dispersed, leaving only small fragments, similar to
Type III clouds in the Kawamura+, (2009, J/ApJS/184/1) classification.
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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 --- ID WISE identifier (GLLL.lll+BB.bbb) (G1)
17- 23 F7.1 Msun Mdense [128/25706]?=-99.9 Aggregate mass of dense gas
25- 31 F7.1 Msun e_Mdense [51/10085]?=-99.9 Mdense 1σ uncertainty
33- 37 F5.1 pc rdense [0.5/10]?=-99.9 Aggregate radius of dense gas
39- 43 F5.1 pc e_rdense [0.1/2]?=-99.9 rdense 1σ uncertainty
45- 51 F7.3 --- DGMF [0.002/0.5]?=-99.9 Dense gas mass fraction
53- 59 F7.3 --- e_DGMF [0.001/0.3]?=-99.9 DGMF 1σ uncertainty
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Global note:
Note (G1): Objects are <[ABB2014] WISE GLLL.lll+BB.bbb> in Simbad.
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 27-Jan-2017