We present the results of an rocket-borne observation of far-infrared [CII] line at 157.7 μm from the diffuse inter-stellar medium in the Ursa Major. We also introduce a part of results on the [CII] emission recently obtained by the IRTS, a liquid-helium cooled 15cm telescope onboard the Space Flyer Unit. From the rocket-borne observation we obtained the cooling rate of the diffuse HI gas due to the [CII] line emission, which is 1.3±0.2 × 10-26 ergss-1 H-1atom. We also observed appreciable [CII] emission from the molecular clouds, with average CII/CO intensity ratio of 420. The IRTS observation provided the [CII] line emission distribution over large area of the sky along great circles crossing the Galactic plane at I = 50° and I = 230°. We found two components in their intensity distributions, one concentrates on the Galactic plane and the another extends over at least 20° in Galactic latitude. We ascribe one component to the emission from the Galactic disk, and the another one to the emission from the local interstellar gas. The [CII] cooling rate of the latter component is 5.6 ± 2.2 ×10.

• H. MATSUHARA(Department of Astrophysics, Nagoya University)
• M. TANAKA(Department of Astrophysics, Nagoya University)
• M. KAWADA(the Institute of Space and Astronautical Science)
• S. MAKIUTI(the Institute of Space and Astronautical Science)
• T. MATSUMOTO(the Institute of Space and Astronautical Science)
• T. NAKAGAWA(the Institute of Space and Astronautical Science)
• H. OKUDA(the Institute of Space and Astronautical Science)
• H. SHIBAI(the Institute of Space and Astronautical Science)
• N. HIROMOTO(Communications Research Laboratory)
• K. OKUMURA(Communications Research Laboratory)
• A. E. LANGE(Observational Cosmology, California Institute of Technology)
• J. J. BOCK(Observational Cosmology, California Institute of Technology)