J/A+A/641/A17 Musca APEX 12CO(2-1), 12CO(3-2) & 12CO(4-3) data (Bonne+, 2020)
Dense gas formation in the Musca filament due to dissipation of a supersonic
converging flow.
Bonne L., Schneider N., Bontemps S., Clarke S. D., Gusdorf A., Lehmann A.,
Steinke M., Csengeri T., Kabanovic S., Simon R., Buchbender C., Guesten R.
<Astron. Astrophys. 641, A17 (2020)>
=2020A&A...641A..17B 2020A&A...641A..17B (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Radio lines ; Carbon monoxide
Keywords: ISM: individual objects: Musca - evolution -
ISM: kinematics and dynamics - shock waves - turbulence -
stars: formation
Abstract:
Observations with the Herschel Space Telescope have established that
most star forming gas is organised in filaments, a finding that is
supported by numerical simulations of the supersonic interstellar
medium (ISM) where dense filamentary structures are ubiquitous. We aim
to understand the formation of these dense structures by performing
observations covering the 12CO(4-3), 12CO(3-2), and various
CO(2-1) isotopologue lines of the Musca filament, using the APEX
telescope. The observed CO intensities and line ratios cannot be
explained by PDR (photodissociation region) emission because of the
low ambient far-UV field that is strongly constrained by the
non-detections of the [CII] line at 158um and the [OI] line at 63um,
observed with the upGREAT receiver on SOFIA, as well as a weak [CI]
609um line detected with APEX. We propose that the observations are
consistent with a scenario in which shock excitation gives rise to
warm and dense gas close to the highest column density regions in the
Musca filament. Using shock models, we find that the CO observations
can be consistent with excitation by J-type low-velocity shocks. A
qualitative comparison of the observed CO spectra with synthetic
observations of dynamic filament formation simulations shows a good
agreement with the signature of a filament accretion shock that forms
a cold and dense filament from a converging flow. The Musca filament
is thus found to be dense molecular post-shock gas. Filament accretion
shocks that dissipate the supersonic kinetic energy of converging
flows in the ISM may thus play a prominent role in the evolution of
cold and dense filamentary structures.
Description:
The 12CO(2-1), 12CO(3-2) and 12CO(4-3) spectral maps at the
northern and southern location of the Musca filament. All data files
are presented in FITS format with as spectral resolution of 0.1km/s.
The units are Ta* in K.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 111 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- 21 I2 --- Nx Number of pixels along X-axis
23- 24 I2 --- Ny Number of pixels along Y-axis
26- 28 I3 --- Nz Number of slices
30- 35 I6 m/s bVRAD Lower value of VRAD interval
37- 41 I5 m/s BVRAD Upper value of VRAD interval
43- 45 I3 m/s dVRAD VRAD resolution
47- 50 I4 Kibyte size Size of FITS file
52- 91 A40 --- FileName Name of FITS file, in subdirectory fits
93-111 A19 --- Title Title of the FITS file
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Acknowledgements:
Lars Bonne, lars.bonne(at)u-bordeaux.fr
(End) Lars Bonne [LAB, France], Patricia Vannier [CDS] 21-Jul-2020