J/A+A/601/A124 Clouds in SEDIGISM science demonstration field (Schuller+, 2017)
SEDIGISM: Structure, excitation, and dynamics of the inner Galactic
interstellar medium.
Schuller F., Csengeri T., Urquhart J.S., Duarte-Cabral A., Barnes P.J.,
Giannetti A., Hernandez A.K., Leurini S., Mattern M., Medina S.-N.X.,
Agurto C., Azagra F., Anderson L.D., Beltran M.T., Beuther H., Bontemps S.,
Bronfman L., Dobbs C.L., Dumke M., Finger R., Ginsburg A., Gonzalez E.,
Henning T., Kauffmann J., Mac-Auliffe F., Menten K.M.,
Montenegro-Montes F.M., Moore T.J.T., Muller E., Parra R.,
Perez-Beaupuits J.-P., Pettitt A., Russeil D., Sanchez-Monge A.,
Schilke P., Schisano E., Suri S., Testi L., Torstensson K., Venegas P.,
Wang K., Wienen M., Wyrowski F., Zavagno A.
<Astron. Astrophys. 601, A124 (2017)>
=2017A&A...601A.124S 2017A&A...601A.124S (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Milky Way ; Molecular clouds ; Interstellar medium ;
Radio lines
Keywords: surveys - Galaxy: structure - radio lines: ISM - ISM: clouds -
ISM: structure
Abstract:
The origin and life-cycle of molecular clouds are still poorly
constrained, despite their importance for understanding the evolution
of the interstellar medium. Many large-scale surveys of the Galactic
plane have been conducted recently, allowing for rapid progress in
this field. Nevertheless, a sub-arcminute resolution global view of
the large-scale distribution of molecular gas, from the diffuse medium
to dense clouds and clumps, and of their relationship to the spiral
structure, is still missing.
We have carried out a systematic, homogeneous, spectroscopic survey of
the inner Galactic plane, in order to complement the many continuum
Galactic surveys available with crucial distance and gas-kinematic
information. Our aim is to combine this data set with recent infrared
to sub-millimetre surveys at similar angular resolutions.
The SEDIGISM survey covers 78deg2 of the inner Galaxy
(-60°<l<+18°, |b|<0.5°) in the J=2-1 rotational transition
of 13CO. This isotopologue of CO is less abundant than 12CO by
factors up to 100. Therefore, its emission has low to moderate optical
depths, and higher critical density, making it an ideal tracer of the
cold, dense interstellar medium. The data have been observed with the
SHFI single-pixel instrument at APEX. The observational setup covers
the 13CO(2-1) and C18O(2-1) lines, plus several transitions from
other molecules.
The observations have been completed. Data reduction is in progress
and the final data products will be made available in the near future.
Here we give a detailed description of the survey and the dedicated
data reduction pipeline. To illustrate the scientific potential of
this survey, preliminary results based on a science demonstration
field covering -20°<l←18.5° are presented. Analysis of the
13CO(2-1) data in this field reveals compact clumps, diffuse clouds,
and filamentary structures at a range of heliocentric distances. By
combining our data with data in the (1-0) transition of CO
isotopologues from the ThrUMMS survey, we are able to compute a 3D
realization of the excitation temperature and optical depth in the
interstellar medium. Ultimately, this survey will provide a detailed,
global view of the inner Galactic interstellar medium at an
unprecedented angular resolution of ∼30".
Description:
Properties of ATLASGAL compact sources located in the SEDIGISM science
demonstration field, and properties of molecular clouds and complexes
extracted from the 13CO(2-1) data covering the same field. The
extraction of clouds was performed using the SCIMES algorithm (Colombo
et al., 2015MNRAS.454.2067C 2015MNRAS.454.2067C).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 86 140 Properties of the ATLASGAL compact clumps located
in the SEDIGISM science demonstration field
tablea1.dat 100 182 Properties of molecular clouds and complexes
extracted with SCIMES from the SEDIGISM
science demonstration field
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See also:
J/ApJS/212/2 : Giant molecular clouds in the 4th Galactic quadrant
(Garcia+, 2014)
J/MNRAS/443/1555 : ATLASGAL massive star forming clumps sample (Urquhart+ 2014)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [AGAL]
5- 18 A14 --- CSC ATLASGAL Compact Source Catalog name,
LLL.lll+BB.bbb
20- 25 F6.1 km/s Vlsr ?=- Centroid velocity
27- 30 F4.1 km/s sigma ?=- Velocity dispersion
(13CO(201) FWHM line-width)
32- 35 F4.1 kpc Dist ?=- Adopted distance
37- 40 F4.1 10+2Msun Mdust ?=- Clump mass, derived from the integrated
870um flux density
42- 45 F4.1 10+2Msun Mvir ?=- Virial mass
47- 49 I3 --- IDcloud ?=- ID number of associated SCIMES cloud
in tablea1.dat
51- 58 A8 --- GMC GMC name of associated 12CO cloud from
Garcia et al. (2014, Cat. J/ApJS/212/2)
60- 70 A11 --- MSFflag Massive star formation associations
(Urquhart et al., 2014,
Cat. J/MNRAS/443/1555) (1)
72- 86 A15 --- Complex Name of associated ATLASGAL complex,
GLLL.lll+BB.bbb
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Note (1): Massive star formation associations flag as follows:
MMB = methanol maser
HII = compact HII region
YSO = massive young stellar object
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID Cloud number in catalogue
5- 20 A16 --- Name Cloud name (SDGLLL.lll+B.bbb)
22- 24 I3 arcsec aaxis Intensity weighted semi-major axis
26- 28 I3 arcsec baxis Intensity weighted semi-minor axis
30- 33 I4 deg PA [] Position angle of semi_major axis
35- 37 F3.1 --- AR Aspect ratio
39- 44 F6.1 km/s Vlsr Centroid velocity
46- 48 F3.1 km/s sigma Velocity dispersion
50- 53 F4.1 K.km/s Average integrated intensity
55- 56 I2 --- Nl Number of dendrogram leaves
58- 62 F5.2 kpc Dist Adopted distance
64- 67 F4.2 kpc e_Dist Uncertainty on distance
69- 71 I3 pc+2 Area Exact area of cloud on sky
73- 76 F4.1 pc Rad Equivalent radius
78- 81 F4.1 pc lmax Projected length
83- 87 F5.1 10+3Msun Mass Total mass
89- 91 I3 Msun/pc2 Sdens Mass surface density
93- 96 F4.1 --- alphaVir Virial parameter
98 I1 --- f_Dist [0/4] Distance flag (1)
100 I1 --- tedge [0/1] Edge Flag: 1 if a cloud is touching the
image edge, 0 otherwise
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Note (1): The distance flag indicates the robustness of the distance
determination (the lower the value of this flag, the more reliable the
distance determination) as follows:
0 = all three methods agree (HiSA, Hi-GAL distance tool and ATLASGAL
determination)
1 = no ATLASGAL counterpart was found and the other two methods agree
2 = only two out of three methods agree
3 = the distance is drawn from one out of two methods
4 = the distance is drawn from the HiSA method only
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Acknowledgements:
Ana Duarte-Cabral, adc(at)astro.cf.ac.uk
James Urquhart, j.s.urquhart(at)kent.ac.uk
Frederic Schuller, schuller(at)mpifr-bonn.mpg.de
(End) F. Schuller [MPIfR Bonn, Germany], P. Vannier [CDS] 09-Mar-2017