J/A+A/631/A72 SABOCA 350um view of ATLASGAL-selected massive clumps (Lin+, 2019)
Fragmentation and filaments at the onset of star and cluster formation.
SABOCA 350 um view of ATLASGAL-selected massive clumps.
Lin Y., Csengeri T., Wyrowski F., Urquhart J.S., Schuller F., Weiss A.,
Menten K.M.
<Astron. Astrophys. 631, A72 (2019)>
=2019A&A...631A..72L 2019A&A...631A..72L (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Millimetric/submm sources ; Molecular clouds
Keywords: star: formation - dust, extinction - infrared: ISM
Abstract:
The structure formation of the dense interstellar material and the
fragmentation of clumps into cores is a fundamental step to understand
how stars and stellar clusters form.
We aim to establish a statistical view of clump fragmentation at
sub-parsec scales based on a large sample of massive clumps selected
from the ATLASGAL survey.
We used the APEX/SABOCA camera at 350um to image clumps at a
resolution of 8.5", corresponding to physical scales of <0.2pc at a
distance <5kpc. The majority of the sample consists of massive clumps
that are weak or in absorption at 24um. We resolve spherical and
filamentary structures and identify the population of compact sources.
Complemented with archival Herschel data, we derive the physical
properties, such as dust temperature, mass and bolometric luminosity
of clumps and cores. We use association with mid-infrared 22-24 m and
70 m point sources to pin down the star formation activity of the
cores. We then statistically assess their physical properties, and the
fragmentation characteristics of massive clumps.
We detect emission at 350um towards all targets and find that it
typically exhibits a filamentary(-like) morphology and hosts a
population of compact sources. Using Gaussclumps we identify 1120
compact sources and derive the physical parameters and star formation
activity for 971 of these, 874 of which are associated with 444
clumps. We find a moderate correlation between the clump fragmentation
levels with the clump gas density and the predicted number of
fragments with pure Jeans fragmentation scenario. We find a strong
correlation between the mass of the most massive fragment and the
total clump mass, suggesting that the self-gravity may play an
important role in the clumps' small scale structure formation.
Finally, due to the improved angular resolution compared to ATLASGAL,
we are able to identify 27 massive quiescent cores with
Mcore>100M☉ within 5kpc; these are massive enough to be
self-gravitating but do not yet show any sign of star-formation. This
sample comprises, therefore, promising candidates of massive
pre-stellar cores, or deeply embedded high-mass protostars.
The submillimeter observations of the massive clumps that are weak or
completely dark at 24um reveal rich filamentary structures and an
embedded population of compact cores. The maximum core mass is likely
determined by the self-gravity of the clump. The rarity of massive
pre-stellar core candidates implies short collapse time-scales for
dense structures.
Description:
Over 10000 compact sources have been identified in the ATLASGAL survey
(Csengeri et al. 2014, Cat. J/A+A/565/A75; Urquhart et al., 2014, Cat.
J/MNRAS/443/1555), and the majority of them (8007) have distance
estimates allowing their physical parameters to be determined
(Urquhart et al., 2018, Cat. J/MNRAS/473/1059). In this study, we use
350 mSABOCA observations to investigate small scale structure of the
clumps. In comparison with the extensive follow-up observations of the
brightest submillimetre clumps selected from the ATLASGAL survey using
both single dish and interferometric observations.
The Gaussclump identified SABOCA compact source basic properties, and
the bolometric properties, distance for both the SABOCA compact
sources and the targeted ATLASGAL clumps derived from SED fitting are
listed. File table1.dat contains SABOCA compact source basic
informations. File table2.dat contains bolometric properties of
ATLASGAL clumps. File table3.dat contains bolometric properties of
SABOCA compact sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 79 1119 List of SABOCA compact sources
table2.dat 62 530 List of ATLASGAL clumps SED results
table3.dat 88 969 List of SABOCA compact sources SED results
list.dat 133 207 List of fits images
fits/* . 207 Individual fits images
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See also:
J/A+A/565/A75 : ATLASGAL. Dust condensations in Galactic plane
(Csengeri+, 2014)
J/MNRAS/443/1555 : ATLASGAL massive star forming clumps sample
(Urquhart+, 2014)
J/MNRAS/473/1059 : Complete sample of Galactic clump properties
(Urquhart+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Name Name of the source (AGLLL.llll+B.bbbb)
19- 26 F8.4 deg RAdeg Right ascension (J2000.0)
28- 35 F8.4 deg DEdeg Declination (J2000.0)
37- 44 F8.4 Jy/beam Fpeak SABOCA 350um peak flux density
46- 50 F5.2 arcsec FWHMmaj Major axis (FWHM size)
52- 56 F5.2 arcsec FWHMmin Minor axis (FWHM size)
58- 62 F5.1 deg PA [] Position angle
64- 77 A14 --- MapName SABOCA map name (fits file in list.dat,
MapName*.fits)
79 A1 --- Flag [cf] Filament flag (1)
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Note (1): Filament flag as follows:
f = filament-like structures
c = compact spherical structures, as reflected in the SABOCA maps
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- Clump Name of the source (GLLL.llll+B.bbbb)
18- 21 F4.1 kpc Dist Distance
23- 26 F4.1 arcsec FWHMmaj Major axis (FWHM size)
28- 31 F4.1 arcsec FWHMmin Minor axis (FWHM size)
33- 37 F5.1 Jy Sint ATLASGAL 870um integrated flux density
39- 42 I4 Msun Mass Mass (1sigma)
44- 49 E6.3 Lsun Lum Luminosity (1sigma)
51- 57 E7.2 cm-2 N(H2) Hydrogen column density
59- 62 F4.1 K Td Dust temperature
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Name of the source (GSLLL.llll+B.bbbb)
19- 22 F4.1 kpc Dist Distance
24- 29 F6.1 Msun Mass Mass (1sigma)
31- 34 F4.1 K Td Dust temperature
36- 43 E8.3 cm-2 N(H2) Hydrogen column density
45- 51 E7.3 Lsun Lum Luminosity (1sigma)
53- 71 A19 --- MIRassoc Mid-infrared/HII compact source association (1)
73- 88 A16 --- Clump ATLASGAL parental clump
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Note (1): the following abbreviations are used:
70q = no PACS 70um compact source from Molinari et al.,
2016A&A...591A.149M 2016A&A...591A.149M, Cat. J/A+A/591/A149
70ct = PACS 70um compact source from Molinari et al.,
2016A&A...591A.149M 2016A&A...591A.149M, Cat. J/A+A/591/A149
22ct = WISE 22um compact source from Cutri et al.,
2012wise.rept....1C, Cat. II/311
24ct = MIPS 24um compact source from Gutermuth et al.,
2015AJ....149...64G 2015AJ....149...64G, Cat. J/AJ/149/64
24sat = MIPS 24um saturated.
HII = (UC)HII regions from Urquhart et al.,
2013MNRAS.435..400U 2013MNRAS.435..400U, Cat. J/MNRAS/435/400),
Kalcheva et al., 2018A&A...615A.103K 2018A&A...615A.103K, Cat. J/A+A/615/A103
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Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 27 I3 --- Ny Number of pixels along Y-axis
29- 32 I4 Kibyte size Size of FITS file
34- 71 A38 --- FileName Name of FITS file, in subdirectory fits
73-117 A45 --- Title Title of the FITS file
120-133 A14 --- Name Name of the source (AGLLL.ll+B.bb)
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Acknowledgements:
Yuxin Lin, ylin(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 19-Sep-2019