A Multi-Line Ammonia Survey of the Galactic Center Region with the Tsukuba 32-m Telescope - I. Observations and Data

Abstract

We present survey data of the NH3 (J, K) = (1, 1)--(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 lowest three transitions were detected with S/N > 3 at 2323 positions (93% of all the on-source positions). Among 2323, the S/N 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 there are two temperature components: cold ($\sim$ 20 K) and warm ($\sim$ 100 K). Typical intensity ratios of Tmb(2,2)/Tmb(1,1), Tmb(4,4)/Tmb(2,2), Tmb(5,5)/Tmb(4,4), and Tmb(6,6)/Tmb(3,3) were 0.71, 0.45, 0.65, and 0.17, respectively. These line ratios correspond to diversity of rotational temperature, which results from mixing of the two temperature components.

19 pages, 11 figures

References in corpus (3)

• The Origin of Diffuse X-ray and $\gamma$-ray Emission from the Galactic Center Region: Cosmic Ray Particles
• Absorption Line Survey of H3+ toward the Galactic Center Sources II. Eight Infrared Sources within 30 pc of the Galactic Center
• The detection of the (J,K)=(18,18) line of NH3

Cited by in corpus (2)

• Atomic Carbon in the Central Molecular Zone of the Milky Way : Possible Cosmic-ray Induced Chemistry or Time-Dependent Chemistry Associated with SNR Sagittarius A East
• HCN $J$=4-3, HNC $J$=1-0, ${\mathrm{H}}^{13}\mathrm{CN}$ $J$=1-0, and $\mathrm{H}{\mathrm{C}}_3\mathrm{N}$ $J$=10-9 Maps of Galactic Center Region II.: Physical Properties of Dense Gas Clumps and Probability of Star Formation