J/MNRAS/447/1996 Ophiuchus molecular cloud CO observations (White+, 2015)
The James Clerk Maxwell telescope Legacy Survey of the Gould Belt:
a molecular line study of the Ophiuchus molecular cloud.
White G.J., Drabek-Maunder E., Rosolowsky E., Ward-Thompson D., Davis C.J.,
Gregson J., Hatchell J., Etxaluze M., Stickler S., Buckle J., Johnstone D.,
Friesen R., Sadavoy S., Natt K.V., Currie M., Richer J.S., Pattle K.,
Spaans M., Di Francesco J., Hogerheijde M.R.
<Mon. Not. R. Astron. Soc., 447, 1996-2020 (2015)>
=2015MNRAS.447.1996W 2015MNRAS.447.1996W (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Carbon monoxide ; Morphology
Keywords: molecular data - stars: formation - ISM: jets and outflows -
ISM: kinematics and dynamics - submillimetre: general
Abstract:
CO, 13CO, and C18O J=3-2 observations are presented of the
Ophiuchus molecular cloud. The 13CO and C18O emission is dominated
by the Oph A clump, and the Oph B1, B2, C, E, F, and J regions. The
optically thin(ner) C18O line is used as a column density tracer, from
which the gravitational binding energy is estimated to be 4.5x1039J
(2282M☉km2/s2). The turbulent kinetic energy is 6.3x1038J
(320M☉km2/s2), or seven times less than this, and therefore
the Oph cloud as a whole is gravitationally bound. 30 protostars were
searched for high-velocity gas, with 8 showing outflows, and 20 more
having evidence of high-velocity gas along their lines of sight. The
total outflow kinetic energy is 1.3x1038J (67M☉km2/s2),
corresponding to 21 percent of the cloud's turbulent kinetic energy.
Although turbulent injection by outflows is significant, but does not
appear to be the dominant source of turbulence in the cloud. 105
dense molecular clumplets were identified, which had radii
∼0.01-0.05pc, virial masses ∼0.1-12M☉, luminosities
∼0.001-0.1K.km/s/pc2, and excitation temperatures ∼10-50K. These
are consistent with the standard Giant Molecular Cloud (GMC) based
size-linewidth relationships, showing that the scaling laws extend
down to size scales of hundredths of a parsec, and to subsolar-mass
condensations. There is however no compelling evidence that the
majority of clumplets are undergoing free-fall collapse, nor that they
are pressure confined.
Description:
The HARP (Heterodyne Array Receiver Programme) receiver contains an
array of 16 heterodyne detectors, arranged in a 4x4 footprint on the
sky. HARP was used to make maps in the CO, 13CO, and C18O J=3-2
lines, where it has a beamsize of 14 arcsec at 345GHz (corresponding
to a linear size of 0.008pc at the Ophiuchus cloud).
The molecular line observations were made up of 3.2h of CO data taken
in 2008 February and March and 16.6h of 13CO and C18O observations
taken during 2008 March, July, and August. The maps were observed
using the standard on-the-fly mapping mode, and referenced against an
off-source reference position at RA(J2000)=16:38:00.6,
Dec(J2000)=-25:36:42.0, which had been verified to show no line
emission from examination of 60s position-switched 'stare'
observation in CO. The CO data were taken with the AutoCorrelation
Spectrometer and Imaging System (ACSIS) using its 250 MHz dual subband
mode that provided 4096 channels, each with a velocity resolution
∼0.05km/s per channel. The 13CO/C18O data were taken
simultaneously with each other, with each subband having a central
rest frequency of 330.587 or 329.330GHz, respectively, providing a
velocity resolution ∼0.055km/s. All of the isotopologue maps
were then further convolved to a resolution of 0.1km/s.
To support the JCMT observations, a deep United Kingdom Infrared
Telescope (UKIRT) image of the Oph region was obtained using a near-IR
K-band filter, and a matching narrow-band H2 image.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 70 105 The clumplet catalogue
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See also:
J/A+A/430/549 : C18O/C17O near rho Oph (Wouterloot+, 2005)
J/A+A/472/519 : N2H+(1-0) maps of Ophiuchus main cloud (Andre+, 2007)
J/A+A/510/A98 : 12C18O(3-2) map of rho Oph A (Liseau+, 2010)
J/A+A/587/A118 : N2H+, N2D+ & C17O spectra in Ophiuchus (Punanova+, 2016)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Sequential number
5- 6 I2 h RAh Clump centre right ascension (J2000)
8- 9 I2 min RAm Clump centre right ascension (J2000)
11- 14 F4.1 s RAs Clump centre right ascension (J2000)
16 A1 --- DE- Clump centre declination sign (J2000)
17- 18 I2 deg DEd Clump centre declination (J2000)
20- 21 I2 arcmin DEm Clump centre declination (J2000)
23- 26 F4.1 arcsec DEs Clump centre declination (J2000)
28- 32 F5.1 arcsec Maj Major axis of the clump deconvolved
from the beam
34- 37 F4.1 arcsec Min Minor axis of the clump deconvolved
from the beam
39- 41 I3 deg PA [] Position angle (measured east of north)
43- 46 F4.2 pc Rad Deconvolved radius of the clump as defined
by Rosolowsky et al. (2006PASP..118..590R 2006PASP..118..590R)
48- 51 F4.2 km/s Vlsr Centre LSR velocity of the clump as
determined from the C18O data
53- 56 F4.2 km/s sigma Centre velocity dispersion of the clump as
determined from the C18O data
58- 62 F5.2 Msun MassVir Viral mass
64- 70 F7.5 K.km/s/pc2 Lum Luminosity estimated from the CO
observations
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 26-May-2017