J/A+A/581/A74 Molecular clouds as viewed by ATLASGAL (Abreu-Vicente+, 2015)
Relationship between the column density distribution and evolutionary class of
molecular clouds as viewed by ATLASGAL.
Abreu-Vicente J., Kainulainen J., Stutz A., Henning T., Beuther H.
<Astron. Astrophys., 581, A74-74 (2015)>
=2015A&A...581A..74A 2015A&A...581A..74A (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Morphology
Keywords: ISM: clouds - evolution - ISM: structure - dust, extinction -
stars: formation - infrared: ISM
Abstract:
We present the first study of the relationship between the column
density distribution of molecular clouds within nearby Galactic spiral
arms and their evolutionary status as measured from their stellar
content. We analyze a sample of 195 molecular clouds located at
distances below 5.5kpc, identified from the ATLASGAL 870µm data. We
define three evolutionary classes within this sample: starless clumps,
star-forming clouds with associated young stellar objects, and clouds
associated with HII regions. We find that the N(H2) probability
density functions (N-PDFs) of these three classes of objects are
clearly different: the N-PDFs of starless clumps are narrowest and
close to log-normal in shape, while star-forming clouds and HII
regions exhibit a power-law shape over a wide range of column
densities and log-normal-like components only at low column densities.
We use the N-PDFs to estimate the evolutionary time-scales of the
three classes of objects based on a simple analytic model from
literature. Finally, we show that the integral of the N-PDFs, the
dense gas mass fraction, depends on the total mass of the regions as
measured by ATLASGAL: more massive clouds contain greater relative
amounts of dense gas across all evolutionary classes.
Description:
We used continuum maps at 870um from ATLASGAL to identify MCs in the
Galactic plane region between l in [9°,21°] and |b|≤1°,
where the rms of the survey is 50mJy/beam.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablef1.dat 71 189 Regions studied in this paper
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See also:
J/A+A/549/A45 : ATLASGAL Compact Source Catalog: 330<l<21 (Contreras+, 2013)
Byte-by-byte Description of file: tablef1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Name Region name
4 A1 --- m_Name Multiplicity index on Name
6- 8 A3 --- Type Type of region
10- 11 I2 h RAh Right ascension (J2000)
13- 14 I2 min RAm Right ascension (J2000)
16- 20 F5.2 s RAs Right ascension (J2000)
22 A1 --- DE- Declination sign (J2000)
23- 24 I2 deg DEd Declination (J2000)
26- 27 I2 arcmin DEm Declination (J2000)
29- 33 F5.2 arcsec DEs Declination (J2000)
35- 38 I4 arcsec Radius ?=- Radius
40- 43 I4 arcsec amaj ?=- Major axis
45- 48 I4 arcsec amin ?=- Minor axis
50- 52 I3 deg Angle ?=- Angle
54- 56 F3.1 kpc Dist Distance (1)
57 A1 --- n_Dist [a] Note on Dist (2)
58 A1 --- leDist Limit flag on e_Dist
59- 61 F3.1 kpc e_Dist ?=- Distance dispersion (3)
63- 71 A9 --- Ref References (4)
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Note (1): The distance shown in this table is the result of averaging all the
distance estimates available for each source.
Note (2): a: these regions have not previous solution for the KDA, but they
show shadows against the NIR background radiation, so we located them at the
near distance solution.
Note (3): The dispersion of all the distance estimates available for each
region, when more than one distance estimates are available.
Note (4): References as follows:
1 = Ellsworth-Bowers et al. (2013ApJ...770...39E 2013ApJ...770...39E, Cat. J/ApJ/770/39)
2 = Tackenberg et al. (2012A&A...540A.113T 2012A&A...540A.113T, Cat. J/A+A/540/A113)
3 = Urquhart et al. (2013MNRAS.435..400U 2013MNRAS.435..400U, Cat. J/MNRAS/435/400)
4 = Wienen et al. (2012A&A...544A.146W 2012A&A...544A.146W, Cat. J/A+A/544/A146)
5 = Roman-Duval et al. (2009ApJ...699.1153R 2009ApJ...699.1153R, Cat. J/ApJ/699/1153)
6 = Marshall et al. (2009ApJ...706..727M 2009ApJ...706..727M, Cat. J/ApJ/706/727)
7 = Simon et al. (2006ApJ...639..227S 2006ApJ...639..227S, Cat. J/ApJ/639/227)
8 = Walsh et al. (1997MNRAS.291..261W 1997MNRAS.291..261W, Cat. J/MNRAS/291/261)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 05-Nov-2015