N(2)H(+) and HC(3)N observations of the Orion A cloud

作者：Tatematsu Ken'ichi^*; Kandori Ryo; Umemoto Tomofumi; Sekimoto Yutaro

来源：Publications of the Astronomical Society of Japan, 2008, 60(3): 407-419.

• ISM : clouds
• ISM : individual (Orion Nebula, Orion Molecular Cloud)
• ISM : molecules
• ISM : structure
• stars : formation

The "integral-shaped filament" of the Orion A giant molecular cloud was mapped in N(2)H(+), and its nor-them end, the OMC-2/3 region, was also observed in HC(3)N and CCS. The results were compared with maps of other molecular lines and the dust continuum emission. The N(2)H(+) distribution is similar to the dust continuum distribution, except for the central part of the Orion Nebula. The distribution of H(13)CO(+) holds a resemblance to that of the dust continuum, but the N(2)H(+) distribution looks more similar to the dust continuum distribution. The N-bearing molecules, N(2)H(+) and NH(3), seem to be more intense in OMC-2, compared with the, H(13)CO(+) and CS distribution. This suggests that OMC-2 has a higher abundance of N-bearing molecules, or a higher filling factor of the quiescent gas. We identified 34 cloud cores from N(2)H(+) data. Over the Orion Nebula region, the N(2)H(+) linewidth is large (1.1-2.1 km s(-1)). In the OMC-2/3 region, it becomes moderate (0.5-1.3 km s(-1)), and it is smaller (0.3-1.1 km s(-1)) in the south of the Orion Nebula. On the other hand, the gas kinetic temperature of the quiescent cores observed in N(2)H(+) is rather constant (similar to 20 K) over the integral-shaped filament. We detected no CCS emission in the OMC-2/3 region. In general, the N(2)H(+) and HC(3)N distribution is quite similar in the OMC-2/3 region, but we observed a displacement between N(2)H(+) and HC(3)N over a 2' scale in OMC-3, which has a chain of Class 0-I protostars (candidates).

• 出版日期2008
• 单位中国科学院国家天文台