J/A+A/649/A113 ISOSS22478 and ISOSS23053 images (Beuther+, 2021)
Fragmentation and kinematics in high-mass star formation.
CORE-extension targeting two very young high-mass star-forming regions.
Beuther H., Gieser C., Suri S., Linz H., Klaassen P., Semenov D.,
Winters J.M., Henning T., Soler J.D., Urquhart J.S., Syed J., Feng S.,
Moeller T., Beltran M.T., Sanchez-Monge A., Longmore S.N., Peters T.,
Ballesteros-Paredes J., Schilke P., Moscadelli L., Palau A., Cesaroni R.,
Lumsden S., Pudritz R., Wyrowski F., Kuiper R., Ahmadi A.
<Astron. Astrophys. 649, A113 (2021)>
=2021A&A...649A.113B 2021A&A...649A.113B (SIMBAD/NED BibCode)
ADC_Keywords: Star Forming Region ; Radio continuum
Keywords: stars: formation - ISM: clouds - ISM: kinematics and dynamics -
stars: massive - stars: protostars
Abstract:
The formation of high-mass star-forming regions from their parental
gas cloud and the subsequent fragmentation processes lie at the heart
of star formation research.
We aim to study the dynamical and fragmentation properties at very
early evolutionary stages of high-mass star formation.
Employing the NOrthern Extended Millimeter Array (NOEMA) and the IRAM
30m telescope, we observe two young high-mass star-forming regions,
ISOSS22478 and ISOSS23053, in the 1.3mm continuum and spectral line
emission at high angular resolution (∼0.8'').
Resolving altogether 29 cores that are largely located along
filament-like structures, we find that these cores follow a mass-size
relation of approximately M∼r3, corresponding to a constant mean
density of roughly 106cm-3^. The correlation of the core masses
with their nearest neighbor separations is consistent with thermal
Jeans fragmentation. Although the kinematics of the two regions appear
very different at first sight -- multiple velocity components along
filaments in ISOSS22478 versus a steep velocity gradient of more than
50km/s/pc in ISOSS23053 -- the findings can all be explained in the
framework of a dynamical cloud collapse scenario.
While our data are consistent with a dynamical cloud collapse scenario
and subsequent thermal Jeans fragmentation, the importance of
additional environmental properties -- e.g., the magnetization of the
gas or external shocks triggering converging gas flows -- is still
less well constrained and requires future investigation.
Description:
The two regions were observed with NOEMA in February and March 2019
with ten antennas in the A, C, and D configurations covering baseline
lengths roughly between 18 and 774m. The sources ISOSS22478 and
ISOSS23053 were observed as six-field and four-field mosaics,
respectively.
The phase centers and velocities of rest vlsr were
RA (J2000.) 22:47:49.22994, Dec 63:56:45.2796
(Gal. long./lat. 109.86/4.26degs) and vlsr=-39.7km/s for ISOSS22478
and RA (J2000.) 23:05:22.46953, Dec 59:53:52.6192
(Gal. long./lat. 109.99/-0.28 degs) and vlsr=-51.7km/s for ISOSS23053.
Flux and bandpass calibration were conducted for both regions with
MWC349 and 3c454.3, respectively. Regularly interleaved observations
of nearby quasars were used for phase and amplitude calibration,
namely, 0016+731 for ISOSS22078 and J2223+628 for ISOSS23053.
Objects:
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RA (2000) DE Designation(s)
-----------------------------------------------------------
22 47 49.23 +63 56 45.3 ISOSS 22478 = ISOSS J22478+6357
23 05 22.47 +59 53 52.6 ISOSS 23053 = ISOSS J23053+5953
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 149 18 List of fits images and datacubes
fits/* . 18 Individual fits images
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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- 31 I2 --- Nz ? Number of slices for the datatcubes
33- 38 I6 m/s bVRAD ? Lower value of VRAD interval
for the datacubes
40- 45 I6 m/s BVRAD ? Upper value of VRAD interval
for the datacubes
47- 49 I3 m/s dVRAD ? VRAD resolution for the datacubes
51- 56 I6 Kibyte size Size of FITS file
58- 99 A42 --- FileName Name of FITS file, in subdirectory fits
101-149 A49 --- Title Title of the FITS file
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Acknowledgements:
Henrik Beuther, beuther(at)mpia.de
(End) Patricia Vannier [CDS] 31-Mar-2021