Molecular Clouds in Cepheus and Cassiopeia

作者：Yoshinori Yonekura, Kazuhito Dobashi, Akira Mizuno, Hideo Ogawa, Yasuo Fukui · 发表于：The Astrophysical Journal Supplement Series · 年份：1997 · DOI：10.1086/312994 · 被引用次数：131 · 研究领域：Astrophysics and Star Formation Studies、Molecular Spectroscopy and Structure、Astro and Planetary Science

A large-scale 13 CO( J = 1-0) survey for nearby molecular clouds was performed toward the Cepheus and Cassiopeia regions (100° < l < 130° and -10° < b < 20°) with the velocity coverage of -40 < V LSR < +20 km s -1 by using the two 4 m millimeter-wave telescopes at Nagoya University. An area of 866 square degrees was covered at an 8' grid spacing with a 2 7 beam, and 48,750 positions were observed. Significant 13 CO emission (≥1.8 K km s -1 = 3 σ) is detected at 1015 positions. On the basis of the 13 CO data, 188 distinct 13 CO clouds are identified whose total mass is 1.0 × 10 5 M ☉ . Physical properties of the 13 CO clouds such as molecular column densities, sizes, and masses are derived for each cloud. Astronomical objects associated with the 13 CO clouds were searched for in the literature: 10 H II regions, eight reflection nebulae, 23 T Tauri type stars, 28 molecular outflows, and 125 IRAS point sources selected as candidates for protostars are likely to be associated with the 13 CO clouds. Statistical studies on the 13 CO clouds detected in this survey have been made. The mass spectra of the 13 CO clouds in Cepheus and Cassiopeia are well represented by a power law, dN cloud / dM cloud ∝ M cloud −α , with α = 1.7 ± 0.3 in a cloud mass range 10 1 -10 5 M ☉ , which is similar to previously observed other regions like Cygnus. We also investigated the relation between the line width and the size of the 13 CO clouds and found that there is no significant correlation among the...