The amanogawa-2SB galactic plane survey I. Data on the galactic equator

Abstract

Using a waveguide-type sideband-separating receiver (2SB receiver) on the Tokyo-NRO 60-cm telescope (renamed the AMANOGAWA telescope), we carried out simultaneous observations in the 12CO (J = 2-1) and 13CO (J = 2-1) lines over the galactic plane l = 10°-245° along b = 0° with a 3′.075 grid. Using the 12CO (J = 1-0) data of Dame et al. (2001, ApJ, 547, 792), who used a beam size almost the same as ours, we show 12CO (J = 2-1)/ 12CO (J = 1-0) and 13CO (J = 2-1)/ 12CO (J = 2-1) intensity ratios on the l-ν map and the intensity correlations among the 12CO (J = 2-1), 13CO (J = 2-1), and 12CO (J = 1-0) lines. As a result, a linear correlation between 12CO (J = 2-1) and 12CO (J = 1-0) and a curved correlation between 12CO (J = 2-1) and 13CO (J = 2-1), as produced by most of the data, have been found. We investigated these correlations with simple radiative transfer equations to ascertain a number of restrictions on the physical quantities of molecular gas on a galactic scale. © 2010. Astronomical Society of Japan.