J/A+A/543/A65 BLAST line survey toward Vela-D cloud (Morales Ortiz+, 2012)
A spectral line survey of the starless and proto-stellar cores detected by
BLAST toward the Vela-D molecular cloud.
Morales Ortiz J.L., Olmi L., Burton M., De Luca M., Elia D., Giannini T.,
Lorenzetti D., Massi F., Strafella F.
<Astron. Astrophys. 543, A65 (2012)>
=2012A&A...543A..65M 2012A&A...543A..65M
ADC_Keywords: Molecular clouds ; Millimetric/submm sources ; Radio lines
Keywords: submillimeter: ISM - stars: formation - ISM: clouds - ISM: molecules -
radio lines: ISM
Abstract:
Starless cores represent a very early stage of the star formation
process, before collapse results in the formation of a central
protostar or a multiple system of protostars. We use spectral line
observations of a sample of cold dust cores, previously detected with
the BLAST telescope in the Vela-D molecular cloud, to perform a more
accurate physical and kinematical analysis of the sources. We present
a 3-mm and 1.3-cm survey conducted with the Mopra 22-m and Parkes 64-m
radio telescopes of a sample of 40 cold dust cores, including both
starless and proto-stellar sources. 20 objects were also mapped using
molecular tracers of dense gas. To trace the dense gas we used the
molecular species NH3, N2H+, HNC, HCO+, H13CO+, HCN and H13CN, where
some of them trace the more quiescent gas, while others are sensitive
to more dynamical processes. The selected cores have a wide variety of
morphological types and also show physical and chemical variations,
which may be associated to different evolutionary phases. We find
evidence of systematic motions in both starless and proto-stellar
cores and we detect line wings in many of the proto-stellar cores. Our
observations probe linear distances in the sources ≲0.1pc, and are
thus sensitive mainly to molecular gas in the envelope of the cores.
In this region we do find that, for example, the radial profile of the
N2H+(1-0) emission falls off more quickly than that of C-bearing
molecules such as HNC(1-0), HCO+(1-0) and HCN(1-0). We also analyze
the correlation between several physical and chemical parameters and
the dynamics of the cores. Depending on the assumptions made to
estimate the virial mass, we find that many starless cores have masses
below the self-gravitating threshold, whereas most of the
proto-stellar cores have masses which are near or above the
self-gravitating critical value. An analysis of the median properties
of the starless and proto-stellar cores suggests that the transition
from the pre- to the proto-stellar phase is relatively fast, leaving
the core envelopes with almost unchanged physical parameters.
Description:
The files are the Mopra telescope data cubes used to produce the maps
in Fig.A1. Units are Ta*[K]. Data cubes are not reduced. Noise in the
maps is not uniform. Frequency resolution is 33.7kHz.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
cubes.dat 79 51 Sources and molecular lines list; resolution is
15arcsec (spatial) and 33.7kHz (frequency)
fits/* . 51 FITS files
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See also:
J/ApJ/707/1824 : BLAST Vela sources (Netterfield+, 2009)
J/ApJ/707/1836 : BLAST survey in Vela-D (Olmi+, 2009)
Byte-by-byte Description of file: cubes.dat
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Bytes Format Units Label Explanations
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1- 33 A33 --- FileName Name of the fits file in subdirectory fits
35 I1 --- CRPIX1 Center pixel axis 1 (Galactic Longitude)
38 I1 --- CRPIX2 Center pixel axis 2 (Galactic Latitude)
41- 48 F8.4 deg CRVAL1 Galactic Longitude, corresponding to CRPIX1
51- 57 F7.4 deg CRVAL2 Galactic Latitude, corresponding to CRPIX2
60- 79 A20 --- Title Title of the file
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Acknowledgements:
Jorge L. Morales Ortiz, jorge.luis379(at)gmail.com
Luca Olmi, olmi.luca(at)gmail.com, INAF-OAA, Italy; UPR-RP, Puerto Rico, USA
(End) Luca Olmi [INAF-OAA; UPR-RP], Patricia Vannier [CDS] 14-May-2012