J/A+A/687/A84 Core to UCHII region evolution in W49A (Nony+, 2024)
Core to ultracompact HII region evolution in the W49A massive protocluster.
Nony T., Galvan-Madrid R., Brouillet N., Suarez G., Louvet F.,
De Pree C.G., Juarez-Gama M., Ginsburg A., Immer K., Lin Y., Liu H.B.,
Roman-Zuniga C.G., Zhang Q.
<Astron. Astrophys. 687, A84 (2024)>
=2024A&A...687A..84N 2024A&A...687A..84N (SIMBAD/NED BibCode)
ADC_Keywords: H II regions ; Protostars ; X-ray sources ;
Millimetric/submm sources
Keywords: star formation - stars: protostars - ISM: clouds - HII regions -
ISM: molecules
Abstract:
We aim to identify and characterize cores in the high-mass
proto-cluster W49, determine their evolutionary stages and measure the
associated lifetimes. We built a catalog of 129 cores extracted from
an ALMA 1.3mm continuum image at 0.26" (2900au) angular resolution.
The association between cores and Hyper/Ultra Compact HII (H/UC HII)
regions was established from the analysis of VLA 3.3cm continuum and
H30alpha line observations. We also looked for emission of hot
molecular cores (HMCs) using the methyl formate doublet at 218.29GHz.
We identified 40 cores associated with an H/UC HII region and 19 HMCs
over the ALMA mosaic. The 52 cores with an H/UC HII region and/or a
HMC are assumed to be high-mass protostellar cores, while the rest of
the core population likely consists in prestellar cores and low-mass
protostellar cores. We found a good agreement between the two tracers
of ionized gas, with 23 common detections and only four cores detected
at 3.3cm and not in H30alpha. The spectral indexes from 3.3cm to 1.3mm
range from 1, for the youngest cores with partially optically thick
free-free emission, to about -0.1, that is optically thin free-free
emission obtained for cores likely more evolved. Using as a reference
the H/UC HII regions, we found the statistical lifetimes of the HMC
and massive protostellar phases in W49N to be about 6x10^4 yr and
1.4x105yr, respectively. We also showed that HMC can co-exist with
H/UC HII regions during a short fraction of the core lifetime, about
2x104yr. This indicates a rapid dispersal of the inner molecule
envelope once the HC HII is formed.
Description:
Catalog of cores detected on the 1.3mm continuum image, listing
their size, flux and association with HC/UC HII regions and hot
molecular cores.
Objects:
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RA (2000) DE Designation(s)
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19 10 13.19 +09 06 12.0 W49N = NAME W 49A NW
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 71 129 Catalog of cores detected on the
1.3mm continuum image
list.dat 162 4 List of fits maps
fits/* . 4 Individual fits maps
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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 --- Seq Core number in the getsf catalog
5- 6 I2 h RAh Right Ascension (ICRS)
8- 9 I2 min RAm Right Ascension (ICRS)
11- 16 F6.3 s RAs Right Ascension (ICRS)
17 A1 --- DE- Declination sign (ICRS)
18- 19 I2 deg DEd Declination (ICRS)
21- 22 I2 arcmin DEm Declination (ICRS)
24- 28 F5.2 arcsec DEs Declination (ICRS)
30- 32 A3 ------ Region Subregion: (W49-)N, (W49-)SW or out(skirts)
34- 37 F4.2 arcsec FWHMa FWHM major axis of the ellipse
39- 42 F4.2 arcsec FWHMb FWHM minor axis of the ellipse
44- 46 I3 deg PA Position Angle (West to North) of the ellipse
48- 53 F6.1 mJy FintB6 Integrated flux in B6 (1.3mm)
55- 59 F5.1 mJy FintBX ?=- Integrated flux in X-band (3.3cm)
61- 65 A5 --- HII [BX RL+] Detection of the H/UCHII region in X
band 3.3 cm (BX) and/or in H30alpha (RL)
67- 69 A3 --- CrossID Identification of the associated H/UCHII
region in the catalogs of De Pree et al.
(1997ApJ...482..307D 1997ApJ...482..307D, 2020AJ....160..234D 2020AJ....160..234D)
[DJW84] W49 AAA in Simbad
71 A1 --- HMC [*] Association to hot molecular core
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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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- 28 I4 --- Ny Number of pixels along Y-axis
30- 52 A23 "datime" Obs.date Observation date
54- 58 I5 Kibyte size Size of FITS file
60-136 A77 --- FileName Name of FITS file, in subdirectory fits
138-162 A25 --- Title Title of the FITS file
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Acknowledgements:
Thomas Noni, thomas.nony(at)inaf.it
(End) Patricia Vannier [CDS] 12-Apr-2024