J/A+A/561/A83 SDC13 infrared dark clouds spectra (Peretto+, 2014)
SDC13 infrared dark clouds: Longitudinally collapsing filaments.
Peretto N., Fuller G.A., Andre P., Arzoumanian D., Rivilla V.M., Bardeau S.,
Duarte Puertas S., Guzman Fernandez J.P., Lenfestey C., Li G.X.,
Olguin F.A., Rock B.R., de Villiers H., Wiliams J.
<Astron. Astrophys. 561, A83 (2014)>
=2014A&A...561A..83P 2014A&A...561A..83P
ADC_Keywords: Nebulae ; Infrared sources ; Interstellar medium ; Spectroscopy
Keywords: stars: formation - ISM: clouds - ISM: kinematics and dynamics -
ISM: structure
Abstract:
Formation of stars is now believed to be tightly linked to the
dynamical evolution of interstellar filaments in which they form. In
this paper we analyze the density structure and kinematics of a small
network of infrared dark filaments, SDC13, observed in both dust
continuum and molecular line emission with the IRAM 30m telescope.
These observations reveal the presence of 18 compact sources amongst
which the two most massive, MM1 and MM2, are located at the
intersection point of the parsec-long filaments. The dense gas
velocity and velocity dispersion observed along these filaments show
smooth, strongly correlated, gradients. We discuss the origin of the
SDC13 velocity field in the context of filament longitudinal collapse.
We show that the collapse timescale of the SDC13 filaments (from 1Myr
to 4Myr depending on the model parameters) is consistent with the
presence of Class I sources in them, and argue that, on top of
bringing more material to the centre of the system, collapse could
generate additional kinematic support against local fragmentation,
helping the formation of starless super-Jeans cores.
SDC13 is composed of three Spitzer Dark Clouds from the Peretto &
Fuller (2009, cat J/A+A/505/405) catalogue (SDC13.174-0.07,
SDC13.158-0.073, SDC13.194-0.073).
Description:
File sd13n2hp.fit contains the 31 N2H+(1-0) spectra presented and
analysed in the paper. The data have been obtained in September 2011
with the IRAM 30m telescope using the EMIR heterodyne receiver. The
rest frequency of the line is 93.2GHz corresponding to a 27"
resolution at the 30m telescope. The off positions, taken 5' away from
SDC13, were checked to ensure no emission was present there. The
pointing was better than 5" and the sky opacity was varying between
0.3 to 2 at 225GHz. We used the FTS spectrometer of the IRAM 30m with
a 50KHz spectral resolution. The data were reduced in CLASS. The
resulting spectra have an rms noise varying from 0.05K to 0.1K in a
0.16km/s channel width. The spectra are in Ta* scale, in Kelvin.
Objects:
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RA (2000) DE Designation(s)
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18 14 29.55 -17 32 32.1 SDC G13.174-0.070 = SDC G13.174-0.070
18 14 28.29 -17 33 27.7 SDC G13.158-0.073 = SDC G13.158-0.073
18 14 32.57 -17 31 33.6 SDC G13.194-0.073 = SDC G13.194-0.073
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 54 31 N2H+(1-0) spectra properties
sd13n2hp.fit 2880 1611 Spectra as single FITS file
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See also:
J/A+A/505/405 : A catalogue of Spitzer dark clouds (Peretto+, 2009)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Sp Spectrum position number (PNN)
5- 6 I2 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 15 F5.2 s RAs Right ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Declination (J2000)
21- 22 I2 arcmin DEm Declination (J2000)
24- 27 F4.1 arcsec DEs Declination (J2000)
29- 33 F5.2 km/s Vel Spectrum best-fit velocity
35- 38 F4.2 km/s FWHM Spectrum best-fit line width
40- 43 F4.2 km/s sig.nt Non-thermal velocity dispersion component
45- 48 F4.2 km/s sig.tot Total (thermal+non-thermal) velocity dispersion
50- 54 A5 --- Name Name, as in sd13n2hp.fit file
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Acknowledgements:
Nicolas Peretto, Nicolas.Peretto(at)astro.cf.ac.uk
(End) Patricia Vannier [CDS] 06-Dec-2013