J/MNRAS/437/1791 RMS survey: molecular observations (Urquhart+, 2014)
The RMS survey: galactic distribution of massive star formation.
Urquhart J.S., Figura C.C., Moore T.J.T., Hoare M.G., Lumsden S.L.,
Mottram J.C., Thompson M.A., Oudmaijer R.D.
<Mon. Not. R. Astron. Soc., 437, 1791-1807 (2014)>
=2014MNRAS.437.1791U 2014MNRAS.437.1791U
ADC_Keywords: Molecular clouds ; Radio lines ; Stars, pre-main sequence ;
Spectroscopy
Keywords: stars: early-type - stars: formation - ISM: molecules -
Galaxy: kinematics and dynamics - Galaxy: structure
Abstract:
We have used the well-selected sample of ∼1750 embedded, young,
massive stars identified by the Red MSX Source (RMS) survey to
investigate the Galactic distribution of recent massive star
formation. We present molecular line observations for ∼800 sources
without existing radial velocities. We describe the various methods
used to assign distances extracted from the literature and solve the
distance ambiguities towards approximately 200 sources located within
the solar circle using archival Hi data. These distances are used to
calculate bolometric luminosities and estimate the survey completeness
(∼2x104L☉). In total, we calculate the distance and
luminosity of ∼1650 sources, one third of which are above the
survey's completeness threshold. Examination of the sample's
longitude, latitude, radial velocities and mid-infrared images has
identified ∼120 small groups of sources, many of which are associated
with well-known star formation complexes, such as G305, G333, W31,
W43, W49 and W51. We compare the positional distribution of the sample
with the expected locations of the spiral arms, assuming a model of
the Galaxy consisting of four gaseous arms. The distribution of young
massive stars in the Milky Way is spatially correlated with the spiral
arms, with strong peaks in the source position and luminosity
distributions at the arms' Galactocentric radii. The overall source
and luminosity surface densities are both well correlated with the
surface density of the molecular gas, which suggests that the massive
star formation rate per unit molecular mass is approximately constant
across the Galaxy. A comparison of the distribution of molecular gas
and the young massive stars to that in other nearby spiral galaxies
shows similar radial dependences. We estimate the total luminosity of
the embedded massive star population to be ∼0.76x108L☉,
30 per cent of which is associated with the 10 most active
star-forming complexes. We measure the scaleheight as a function of
the Galactocentric distance and find that it increases only modestly
from ∼20-30pc between 4 and 8kpc, but much more rapidly at larger
distances.
Description:
Results of molecular line observation, complex parameters and HI
self-absorption solutions for the sources located within the Solar
circle.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 141 1797 Molecular line parameters
table2.dat 98 117 Complex parameters derived by averaging all
associated members
table3.dat 92 226 Kinematic distances and distance ambiguity
solutions
fig1/* . 1134 Plots of figure 1, CS, 13CO and/or NH3 spectra
fig4/* . 448 Plots of figure 4, SGPS HI spectra
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See also:
J/A+A/476/1019 : Southern candidate massive YSOs RMS survey (Mottram+, 2007)
J/A+A/487/253 : RMS survey: 13CO observations of YSOs (Urquhart+ 2008)
J/A+A/501/539 : RMS survey. 6cm observations of YSOs (Urquhart+, 2009)
J/A+A/507/795 : RMS survey: water masers of YSOs (Urquhart+, 2009)
J/A+A/510/A89 : RMS survey of young massive stars in far-IR (Mottram+, 2010)
J/MNRAS/410/1237 : Red MSX survey (RMS) massive young stars (Urquhart+, 2011)
J/A+A/525/A149 : Red MSX Survey (RMS) YSOs bolometric fluxes (Mottram+, 2012)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- MSX Source name (GLLL.llll+BB.bbbb)
18 A1 --- --- [_]
19 I1 --- m_MSX [1/2]? Multipliciy index on MSX
21- 22 I2 h RAh Source right ascension (J2000)
24- 25 I2 min RAm Source right ascension (J2000)
27- 31 F5.2 s RAs Source right ascension (J2000)
33 A1 --- DE- Source declination sign (J2000)
34- 35 I2 deg DEd Source declination (J2000)
37- 38 I2 arcmin DEm Source declination (J2000)
40- 43 F4.1 arcsec DEs Source declination (J2000)
45- 56 A12 --- Trans Molecular transition (1)
58- 60 I3 mK rms ?=- Noise per spectral channel
62- 68 F7.2 km/s VLSR ?=-999 Radial velocity of the source
70- 76 F7.2 km/s e_VLSR ?=-999 Error in radial velocity of the source
78- 84 F7.2 K Ta* ?=-999 Measured antenna temperature - Intensity
86- 92 F7.2 K e_Ta* ?=-999 Error in measures antenna temperature
94-100 F7.2 km/s FWHM ?=-999 Line width
102-108 F7.2 km/s e_FWHM ?=-999 Error Line width
110-141 A32 --- FileName Name of the file in fig1 Subdirectory,
with .png or .eps extension
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Note (1): the transitions are:
* 13CO(J=1-0) line at 110.20GHz
* NH3(1,1) inversion line at 23.694GHz
* NH3(2,2) inversion line at 23.722GHz
* CS(J=2-1) line at 97.98GHz
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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 --- Gname Complex galactic name (GLLL.lll+BB.bbb)
17- 44 A28 --- Complex Star forming complex name(s)
46- 52 F7.3 deg GLON Galactic Longitude
54- 59 F6.3 deg GLAT Galactic Latitude
61- 67 F7.2 km/s VLSR Local Standard of Rest velocity of the complex
69- 70 I2 --- N Number of RMS sources associated with complex
72- 75 F4.1 kpc Dist Heliocentric distance
77- 82 F6.1 pc Z Distance from the Galactic mid-plane
84- 88 F5.2 kpc Rgc Galactocentric radius - distance from GC
90- 93 F4.2 Lsun logL Total bolometric luminosity of associated
sources
95- 98 F4.2 % fL Fraction of total RMS luminosity in the Galaxy
Lbol/LGalaxy
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- MSX Source name
19- 26 F8.4 deg GLON Galactic Longitude
28- 34 F7.4 deg GLAT Galactic Latitude
36- 41 F6.1 km/s VLSR ?=- Radial velocity of the complex
43- 45 F3.1 kpc Dnear ?=- Kinematic near distance
47- 50 F4.1 kpc Dfar ?=- Kinematic far distance
52- 53 A2 --- n_Dist [NF? ] Kinematic distance solution
(N=near, F=far, t=tangent, lower confidence =?)
55- 58 F4.1 kpc Dist ?=- Heliocentric distance
60- 62 F3.1 kpc Rgc ?=- Galactocentric radius (distance from GC)
64- 69 F6.1 pc Z ?=- Distance from the Galactic mid-plane
71- 92 A22 --- FileName Name of the file in fig4 Subdirectory,
with .png or .ps extension
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Acknowledgements:
James Urquhart, jurquhart(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 30-Jan-2014