J/A+A/584/A67 IRDC18223 images (Beuther+, 2015)
Filament fragmentation in high-mass star formation.
Beuther H., Ragan S.E., Johnston K., Henning T., Hacar A., Kainulainen J.T.
<Astron. Astrophys. 584, A67 (2015)>
=2015A&A...584A..67B 2015A&A...584A..67B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, early-type ; Molecular clouds
Keywords: stars: formation - stars: early-type - stars: individual: IRDC 18223 -
stars: massive - ISM: clouds - ISM: structure
Abstract:
Filamentary structures in the interstellar medium are crucial
ingredients of the star formation process. They fragment to form
individual star-forming cores, and at the same time they may also
funnel gas toward the central gas cores, providing an additional gas
reservoir.
We want to resolve the length scales for filament formation and
fragmentation (resolution ≤0.1pc), in particular the Jeans length
and cylinder fragmentation scale.
We have observed the prototypical high-mass star-forming filament
IRDC 18223 with the Plateau de Bure Interferometer (PdBI) in the
3.2mm continuum and N2H+(1-0) line emission in a ten-field mosaic
at a spatial resolution of ∼4° (∼14000au).
Description:
The IRDC 18223 filament was observed during a series of 8 tracks
between June 2013 and April 2014 in the D- (with 5 antennas) and
C-array (with 6 antennas) configurations of the Plateau de Bure
Interferometer (PdBI). The projected baselines ranged between 15 and
175m. While the absolute reference position was RA=18:25:09.533 and
Dec=-12:43:55.90 (J2000), ten mosaic pointings were required to cover
the length of the filament. The adopted velocity of rest vlsr of the
system is 45.3km/s. Bandpass calibration was conducted with either of
3C 279, 2200+420, 1633+382 or 3C 345. The absolute flux calibration
was performed with MWC349 and is estimated to be correct to within
∼15%. Phase and amplitude calibration was conducted with regular
observations of the quasars 1730-130 and 1741-038. The spectral
coverage of the wide-band receiver and correlator unit ranged from
91.53 to 95.14GHz. Almost the whole bandpass was used to extract the
3.2mm continuum emission (a small band around the N2H+(1-0) was
excluded). The narrow-band correlator units focused mainly on the
N2H+(1-0) and 13CS(2-1) lines. The nominal channel separation
was 0.039MHz, and we smoothed the data to 0.2km/s spectral resolution
for our final data-cubes.
Objects:
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RA (2000) DE Designation(s)
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18 25 10.0 -12 44 00 IRDC 18223 = [BSM2002] 18223-1243 2
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 132 3 List of fits files
fits/* . 3 Individual fits files
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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 (J2000)
10- 18 F9.5 deg DEdeg Declination (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 27 I4 --- Ny Number of pixels along Y-axis
29- 31 I3 --- Nz ? Number of slices for data cube
33- 37 I5 m/s VRAD Radial velocity or lower value of radial
velocity interval for datacude
39- 43 I5 m/s BVRAD ? Upper value of radial velocity interval
for datacude
45- 47 I3 m/s dVRAD ? Radial velocity resolution for datacude
49- 54 I6 Kibyte size Size of FITS file
56- 86 A31 --- FileName Name of the fits file in subdirectory fits
88-132 A45 --- Title Title of the file
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Acknowledgements:
Henrik Beuther, beuther(at)mpia.de
(End) Patricia Vannier [CDS] 16-Oct-2015