Astronomy and Astrophysics – Astronomy
Scientific paper
Nov 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992isasr.650....1s&link_type=abstract
ISAS Research Note, vol.650, p.1-81
Astronomy and Astrophysics
Astronomy
Atomic Processes, Galaxies: Structure, Galaxies: The Galaxy, Ingrared: Spectra, Interstellar: Abundances, Interstellar: Matter
Scientific paper
A far-infrared emission line of C+ ion ([CII] 158 μm) was detected in an extensive region (30o <= l <= 51o along the Galactic plane. The [CII] line is bright and extended far from discrete luminous HII regions. Latitudinal and longitudinal profiles of the [CII] intensity distribution are quite similar to those of 12CO(J = 1-0) and 100 μm continuum, but completely different from those of HI 21 cm. The diffuse [CII] emission probably comes from the photodissociated C+ regions enveloping giant molecular clouds exposed to the general interstellar UV radiation field, namely, "diffuse photodissociation regions" . The extended-low-density ionized gas might also contribute to the diffuse [CII] emission. The mass of the C+ regions is as much as 35-50% of that of CO molecular gas. The total luminosity of the [CII] Iine emitted from the inner Galactic disk amounts to 2.8(±1.1) × 107 Lodot, or about 0.36(+0.28,-0.17)% of the total far-infrared luminosity of the same region. For the observations, Balloon-Borne Infrared Telescope (BIRT) was used. It has been developed for far-infrared astronomy by a joint project (BIRT project) between the Institute of Space and Astronautical Science (ISAS) and Kyoto University in Japan. BIRT has a 50 cm reflector telescope mounted on an alt-azimuthal pointing system actuated by a control-moment gyro (CMG) torquer in the azimuth. The pointing and tracking are accomplished by a unique offset guide system which utilizes a star tracker and a star field camera mounted on a two-axis offset gimbals. The motion of the gimbals is controlled by an on-board CPU which computes and corrects the rotation rate of the offset direction caused by the celestial diurnal motion as well as the horizontal motion of the balloon gondola. BIRT has been flown 6 times at Alice Springs, Australia in 1985 and 1986, and 2 times at Palestine, Texas in 1988. The pointing and tracking accuracies were better than I arcmin and the peak-to-peak attitude stability was sma.]ler than 30 arcsec in those fiights. The last two flights, at which liquid helium cooled Fabry-Perot spectrometer was mounted on the Nasmyth focus, were quite successful for observing far-infrared spectral lines of [CII] (158 μm) and [OI] (63 μm) over wide areas of several galactic nebulae and Milky Way. These observations have demonstrated that balloon-borne observation is a quite useful method for far-infrared spectroscopy. Chapter I is an introduction for the far-infrared spectroscopic study. Chapter 2 describes the balloon-borne infrared telescope, BIRT. Chapter 3 shows a major result of our balloon observation., that is, a detection of the diffuse photodissociation regions. Chapter 2 and 3 refer to [Shibai et al. 1990] and [Shibai et al. 1991], respectively. Appendix A is a review of the far-infrared line observations. In appendix B and C, I provide compilations of far-infrared line parameters and observational work, respectively.
No associations
LandOfFree
Observational Study of Large-Scale [CII] Emission by Balloon-Borne Infrared Telescope (BIRT) does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Observational Study of Large-Scale [CII] Emission by Balloon-Borne Infrared Telescope (BIRT), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Observational Study of Large-Scale [CII] Emission by Balloon-Borne Infrared Telescope (BIRT) will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1554274