A multi-line ammonia survey of the Galactic center region with the Tsukuba 32 m telescope. I. Observations and data

• Published in: Publications of the Astronomical Society of Japan Vol. 68; no. 5
• Main Authors: Arai, Hitoshi, Nagai, Makoto, Fujita, Shinji, Nakai, Naomasa, Seta, Masumichi, Yamauchi, Aya, Kaneko, Hiroyuki, Hagiwara, Kenzaburo, Mamyoda, Koh-ichi, Miyamoto, Yusuke, Horie, Masa-aki, Ishii, Shun, Koide, Yusuke, Ogino, Mitsutoshi, Maruyama, Masaki, Hirai, Katsuaki, Oshiro, Wataru, Nagai, Satoshi, Akiyama, Daiki, Konakawa, Keita, Nonogawa, Hiroaki, Salak, Dragan, Terabe, Yuki, Nihonmatsu, Yoshiki, Funahashi, Fumiyoshi
• Format: Journal Article
• Language: English
• Published: Oxford University Press 01.10.2016
• Subjects: ISM: clouds; Galaxy: structure; radio lines: ISM; ISM: molecules; Galaxy: center
• ISSN: 0004-6264; 2053-051X
• DOI: 10.1093/pasj/psw072

Abstract We present survey data of six NH3 (J, K) = (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), and (6, 6) lines, simultaneously observed with the Tsukuba 32 m telescope, in the main part of the central molecular zone of the Galaxy. The total number of on-source positions was 2655. The three lower transitions were detected with S/N > 3 at 2323 positions (93% of all the on-source positions). Among 2323, the S/N 's of (J, K) = (4, 4), (5, 5), and (6, 6) exceeded 3.0 at 1426(54%), 1150(43%), and 1359(51%) positions, respectively. Simultaneous observations of the lines enabled us to accurately derive intensity ratios with less systematic errors. Boltzmann plots indicate that there are two temperature components: cold (∼20 K) and warm (∼100 K). Typical intensity ratios of T mb(2, 2)/T mb(1, 1), T mb(4, 4)/T mb(2, 2), T mb(5, 5)/T mb(4, 4), and T mb(6, 6)/T mb(3, 3) were 0.71, 0.45, 0.65, and 0.17, respectively. These line ratios correspond to the diversity of the rotational temperature, which results from mixing of the two temperature components.