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J/A+A/600/L10       Massive cluster progenitors from ATLASGAL  (Csengeri+, 2017)

ALMA survey of massive cluster progenitors from ATLASGAL. Limited fragmentation at the early evolutionary stage of massive clumps. Csengeri T., Bontemps S., Wyrowski F., Motte F., Menten K.M., Beuther H., Bronfman L., Commercon B., Chapillon E., Duarte-Cabral A., Fuller G.A., Henning T., Leurini S., Longmore S., Palau A., Peretto N., Schuller F., Tan J.C., Testi L., Traficante A., Urquhart J.S. <Astron. Astrophys. 600, L10 (2017)> =2017A&A...600L..10C (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Millimetric/submm sources ; Morphology Keywords: stars: formation - stars: massive - submillimeter: ISM Abstract: The early evolution of massive cluster progenitors is poorly understood. We investigate the fragmentation properties from 0.3pc to 0.06pc scales of a homogenous sample of infrared-quiet massive clumps within 4.5kpc selected from the ATLASGAL survey. Using the ALMA 7m array we detect compact dust continuum emission towards all targets and find that fragmentation, at these scales, is limited. The mass distribution of the fragments uncovers a large fraction of cores above 40M, corresponding to massive dense cores (MDCs) with masses up to ∼400M. Seventy-seven percent of the clumps contain at most 3 MDCs per clump, and we also reveal single clumps/MDCs. The most massive cores are formed within the more massive clumps and a high concentration of mass on small scales reveals a high core formation efficiency. The mass of MDCs highly exceeds the local thermal Jeans mass, and we lack the observational evidence of a survey efficiently high level of turbulence or strong enough magnetic fields to keep the most massive MDCs in equilibrium. If already collapsing, the observed fragmentation properties with a high core formation efficiency are consistent with the collapse setting in at parsec scales. Description: We present observations carried out in Cycle 2 with the ALMA 7m array using 9 to 11 of the 7m antennas with baselines ranging between 8.2m (9.5kλ) to 48.9m (53.4kλ). We used a low-resolution wide-band set-up in Band 7, yielding 4x1.75GHz effective bandwidth with a spectral resolution of 976.562kHz. The four basebands were centred on 347.331, 345.796, 337.061, and 335.900GHz, respectively. The primary beam at this frequency is 28.9". Each source was observed for ∼5.4min in total. The system temperature, Tsys, varies between 100-150K. The targets were split into five observing groups according to Galactic longitude. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 91 100 Summary of physical properties of the sample
See also: J/A+A/570/A65 : ATLASGAL massive clumps CO depletion (Giannetti+, 2014) Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 19 A19 --- Source Source name (LLL.llll+B.bbbb-MMN) 20 A1 --- n_Source [*] Note on Source (1) 22- 30 F9.5 deg RAdeg Right ascension (J2000) 32- 40 F9.5 deg DEdeg Declination (J2000) 42- 45 F4.2 Jy/beam Fnu Peak flux at 345GHz 47- 51 F5.2 Jy Snu Integrated flux density at 345GHz 53- 57 F5.2 arcsec ThetaA FWHM major axis 59- 63 F5.2 arcsec ThetaB FWHM minor axis 65- 68 F4.2 arcsec Beam Beam size as the geometric mean of the beam major and minor axes 70- 73 F4.2 arcsec FWHM Beam convolved angular source size 75- 78 F4.2 kpc Dist Distance from Csengeri et al. (2017, in prep.) 80- 85 F6.2 Msun Mcore Core mass as described in the main text 87- 91 F5.2 g/cm2 Sigmacore Core surface density as described in the main text
Note (1): * for unresolved sources.
History: From electronic version
(End) Patricia Vannier [CDS] 31-Mar-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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