J/A+A/646/A170 The Serpens filament 13CO, C18O and C17O datacubes (Gong+, 2021)
Physical and chemical structure of the Serpens filament:
fast formation and gravity-driven accretion.
Gong Y., Belloche A., Du F.J., Menten K.M., Henkel C., Li G.X., Wyrowski F.,
Mao R.Q.
<Astron. Astrophys. 646, A170 (2021)>
=2021A&A...646A.170G 2021A&A...646A.170G (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Interstellar medium ; Radio lines
Keywords: ISM: clouds - ISM: individual object (the Serpens filament) -
radio lines: ISM - ISM: kinematics and dynamics - ISM: molecules -
ISM: structure
Abstract:
The Serpens filament, a prominent elongated structure in a relatively
nearby molecular cloud, is believed to be at an early evolutionary
stage, so studying its physical and chemical properties can shed light
on filament formation and early evolution.
The main goal is to address the physical and chemical properties as
well as dynamical state of the Serpens filament at a spatial
resolution of ∼0.07pc and a spectral resolution of ∼0.1∼km/s.
We performed 13CO (1-0), C18O (1-0), C17O (1-0), 13CO (2-1),
C18O (2-1), and C17O (2-1) imaging observations toward the Serpens
filament with the IRAM-3 m and APEX telescopes.
Widespread narrow 13CO (2-1) self-absorption is observed in this
filament, causing the 13CO morphology to be different from the
filamentary structure traced by C18O and C17O. Our excitation
analysis suggests that the opacities of C18O transitions become
higher than unity in most regions, and this analysis confirms the
presence of widespread CO depletion. Further we show that the local
velocity gradients have a tendency to be perpendicular to the
filament's long axis in the outskirts and parallel to the large-scale
magnetic field direction. The magnitudes of the local velocity
gradients decrease toward the filament's crest. The observed velocity
structure can be a result of gravity-driven accretion flows. The
isochronic evolutionary track of the C18O freeze-out process
indicates the filament is young with an age of ≲2Myr.
We propose that the Serpens filament is a newly-formed
slightly-supercritical structure which appears to be actively
accreting material from its ambient gas.
Description:
We include six FITS files containing the data-cubes
(position-position-velocity) of 13CO(1-0), 13CO(2-1), C18O(1-0),
C18O(2-1), C17O (1-0), and C17O (2-1) emission lines. We used
the J2000 equatorial coordinates for the spatial dimensions and Vlsr
for the spectral dimension. All the intensities have been converted to
a scale of main beam temperatures in units of K.
Objects:
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RA (2000) DE Designation(s)
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18 28 +00 49 The Serpens filament = NAME Filament in Serpens Cloud
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 109 6 List of fits datacubes
fits/* . 6 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- 30 I3 --- Nz Number of slices
32- 41 F10.3 MHz nu Rest frequency
43- 44 I2 arcsec FWHM Beam size
46- 53 F8.1 m/s bVRAD Lower value of VRAD interval
55- 61 F7.1 m/s BVRAD Upper value of VRAD interval
63- 70 F8.4 m/s dVRAD VRAD resolution
72- 76 I5 Kibyte size Size of FITS file
78- 88 A11 --- FileName Name of FITS file, in subdirectory fits
90-109 A20 --- 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] 25-Dec-2020