Large-scale (CO)-C-13 J=5 -> 4 and [C I] mapping Of Orion A

Citation
R. Plume et al., Large-scale (CO)-C-13 J=5 -> 4 and [C I] mapping Of Orion A, ASTROPHYS J, 539(2), 2000, pp. L133-L136
Citations number
24
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
539
Issue
2
Year of publication
2000
Part
2
Pages
L133 - L136
Database
ISI
SICI code
0004-637X(20000820)539:2<L133:L(J-4A>2.0.ZU;2-A
Abstract
We present maps of the (CO)-C-13 J = 5 --> 4 (551 GHz) and [C I] P-3(1) --> P-3(0) (492 GHz) emission in the Orion A molecular cloud, covering a 0 deg rees.5 x 2 degrees area. A large velocity gradient (LVG) analysis of (CO)-C -13 J = 5 --> 4 and J = 1 --> 0 suggests that the gas temperatures in the n orthern part of OMC-1. (north of Delta delta = -20') are similar to 45 K an d are, on average, at least 20 K higher than those to the south. The averag e (CO)-C-13 column density is log (N/cm(-2)) = 16.4 +/- 0.3 and is fairly c onstant throughout the cloud, even in the low-temperature region south of B N/KL. LVG modeling of the [C I] emission shows a typical C-0 column density of 2 x 10(17) cm(-2), which yields a C/CO abundance ratio in the cloud of similar to 0.1 (rising to levels in excess of 0.5 at the cloud edges). Comp arison of the Delta-variance (which measures spatial structure in a manner similar to a power spectrum) of the Submillimeter Wave Astronomy Satellite [C I], Five College Radio Astronomy Observatory (CO)-C-13 J = 1 --> 0, and CS J = 1 --> 0 velocity-integrated maps suggests that the [C I] and (CO)-C- 13 emission arise from the same gas. In contrast, the CS emission likely or iginates in gas that is considerably more clumpy.