the large scale observation of our galactic plane with a balloon telescope in the [c ii] 158 mm line shows that our galactic center has lower [c ii]/fir continuum intensity ratio than that in general galactic plane region. the line/continuum ratio has rather flat distribution over wide area of the general galactic plane. thus, this large scale (500pc) defect of [c ii] line intensity is not local effect, but is important for galactic structure. we have proposed two possible sources of the [c ii] defect: 1) molecular self-shielding in dense molecular clouds in the galactic center region; 2) added heating of grains by late-type stars in the bulge. these two decrease formation of c+ ions, which emit [c ii] line, and/or excitation of the ions to upper level of the transition. we propose observation of [c ii] intensity along the major axis of m31, whose center has larger bulge and lesser molecular gas than the galactic center. the center with different physical conditions from our galactic center should give answer for this problem.
Instrument
LWS01
Temporal Coverage
1997-06-18T13:23:49Z/1997-07-10T13:13:33Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
European Space Agency, 1998, Fir Spectroscopy Of M31 Seach For Square_Bracket_Openc Iisquare_Bracket_Close Deficit, 1.0, European Space Agency, https://doi.org/10.5270/esa-eez3dpc
