J/A+A/620/A62 Serpens filament emission lines datacubes (Gong+, 2018)
The Serpens filament at the onset of slightly supercritical collapse.
Gong Y., Li G.X., Mao R.Q., Henkel C., Menten K.M., Fang M., Wang M.,
Sun J.X.
<Astron. Astrophys. 620, A62 (2018)>
=2018A&A...620A..62G 2018A&A...620A..62G (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Interstellar medium ; Radio lines
Keywords: ISM: clouds - ISM: molecules - radio lines: ISM - line: profiles -
ISM: kinematics and dynamics
Abstract:
The Serpens filament, as one of the nearest infrared dark clouds, is
regarded as a pristine filament at a very early evolutionary stage of
star formation. In order to study its molecular content and dynamical
state, we mapped this filament in seven species including C18O,
HCO+, HNC, HCN, N2H+, CS, and CH3OH. Among them, HCO+, HNC,
HCN, and CS show self-absorption, while C18O is most sensitive to
the filamentary structure. A kinematic analysis demonstrates that this
filament forms a velocity-coherent (trans-)sonic structure, a large
part of which is one of the most quiescent regions in the Serpens
cloud. Widespread C18O depletion is found throughout the Serpens
filament. Based on the Herschel dust-derived H2 column density map,
the line mass of the filament is 36-41∼M☉/pc, and its full width
at half maximum width is 0.17±0.01pc, while its length is ∼1.6pc.
The inner radial column density profile of this filament can be well
fitted with a Plummer profile with an exponent of 2.2±0.1, a scale
radius of 0.018±0.003pc and a central density of
(4.0±0.8)x104cm-3. The Serpens filament appears to be slightly
supercritical. The widespread blue-skewed HNC and CS line profiles and
HCN hyperfine line anomalies across this filament indicate radial
infall in parts of the Serpens filament. C18O velocity gradients
also indicate accretion flows along the filament. The velocity and
density structures suggest that such accretion flows are likely due to
a longitudinal collapse parallel to the filament's long axis. Both the
radial infall rate and the longitudinal accretion rate along the
Serpens filament are lower than all previously reported values in
other filaments. This indicates that the Serpens filament lies at an
early evolutionary stage when collapse has just begun, or that thermal
and non-thermal support are effective in providing support against
gravity.
Description:
We carried out multiple molecular line observations (project code:
17A004) toward the Serpens filament with the Purple Mountain
Observatory 13.7m (PMO-13.7m) telescope from 2017 May 12 to 17.
We include seven FITS files containing the data-cubes
(position-position-velocity) of C18O, CS, HCO+, HCN, HNC,
N2H+, and CH3OH emission lines. We used the J2000 equatorial
coordinates for the spatial dimensions and Vlsr for the spectral
dimension. The gridded data have effective angular resolutions of 60".
All the intensities have been converted to a scale of main beam
temperatures in units of K.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 107 7 List of fits datacubes
fits/* . 7 Individual fits datacubes
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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- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 31 I4 --- Nz Number of slices
33- 42 F10.3 MHz nu Rest frequency
44- 45 I2 arcsec FWHM [60] Beam size
47- 55 F9.2 m/s bVel Lower value of velocity interval
57- 64 F8.1 m/s BVel Upper value of velocity interval
66- 73 F8.4 m/s dVel Velocity resolution
75- 79 I5 Kibyte size Size of FITS file
81- 90 A10 --- FileName Name of FITS file, in subdirectory fits
92-107 A16 --- Title Title of the FITS file
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Acknowledgements:
Yan Gong, ygong(at)mpifr-bonn.mpg.de
(End) Yan Gong [MPIFR], Patricia Vannier [CDS] 24-Sep-2018