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Title: EXTENSIVE [C I] MAPPING TOWARD THE ORION-A GIANT MOLECULAR CLOUD

We have carried out wide-field (0.17 deg{sup 2}) and high-angular resolution (21.''3 {approx} 0.04 pc) observations in the [C I] line toward the Orion-A giant molecular cloud with the Atacama Submillimeter Telescope Experiment 10 m telescope in the On-The-Fly mode. The overall features of the [C I] emission are similar to those of the {sup 12}CO (J = 1-0) emission by Shimajiri et al. in 2011; the total intensity ratio of the [C I] to CO emission ranges from 0.05 to 0.2. The optical depth of the [C I] emission is found to be 0.1-0.75, suggesting optically thin emission. The column density of the [C I] emission is estimated to be (1.0-19) Multiplication-Sign 10{sup 17} cm{sup -2}. These results are consistent with the results of the previous [C I] observations with a low-angular resolution of 2.'2. In the nearly edge-on photon-dominated regions (PDRs) and their candidates of the Orion Bar, DLSF, M 43 Shell, and Region D, the distributions of the [C I] emission coincide with those of the {sup 12}CO emission, inconsistent with the prediction by the plane-parallel PDR model. In addition, the [C I] distribution in the Orion A cloud is found to be more similar to thosemore » of the {sup 13}CO (J = 1-0), C{sup 18}O (J = 1-0), and H{sup 13}CO{sup +} (J = 1-0) lines than that of the {sup 12}CO (J = 1-0) line, suggesting that the [C I] emission is not limited to the cloud surface, but is tracing the dense, inner parts of the cloud.« less
Authors:
; ;  [1] ; ;  [2] ; ;  [3] ;  [4] ;  [5]
  1. Nobeyama Radio Observatory, 462-2 Nobeyama Minamimaki, Minamisaku District, Nagano Prefecture 384-1305 (Japan)
  2. Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)
  3. Ibaraki University, 2-1-1 Bunkyo Mito, Ibaraki Prefecture 310-8512 (Japan)
  4. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara 252-5210 (Japan)
  5. National Astronomical Observatory of Japan, 2-21-1 Osawa Mitaka, Tokyo 181-0015 (Japan)
Publication Date:
OSTI Identifier:
22136527
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 774; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON MONOXIDE; CLOUDS; DENSITY; EMISSION; GIANT STARS; MAPPING; MOLECULES; PHOTONS; RESOLUTION; TELESCOPES