Astronomy and Astrophysics – Astrophysics
Scientific paper
Jan 1978
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1978apjs...36...77d&link_type=abstract
Astrophysical Journal Supplement Series, vol. 36, Jan. 1978, p. 77-114.
Astronomy and Astrophysics
Astrophysics
164
Extragalactic Radio Sources, Hydrogen Clouds, Interstellar Matter, Milky Way Galaxy, Nebulae, Absorption Spectra, Decimeter Waves, Diagrams, Radial Velocity, Spatial Distribution, Spin Temperature, Temperature Profiles, Velocity Distribution
Scientific paper
Emission-absorption observations of the interstellar medium in the directions of 27 extragalactic sources at high and intermediate galactic latitudes are reported which were performed at a wavelength of 21 cm with the upgraded Arecibo telescope (sensitivity of 6 K/Jy, HPBW of about 3.2 arcmin). The resulting spectra are presented along with the corresponding column-density and spin-temperature profiles. The data are used to determine the temperature distribution of interstellar material, the relationship between temperature and optical depth among absorption features, and the velocity distribution of absorbing clouds. The results are shown to confirm the previous detection of cold clouds (spin temperatures between approximately 30 and 125 K) and a hot neutral medium (spin temperature of at least about 1500 K); in addition, neutral material has been detected at all intermediate temperatures. The absorption profile for each line of sight is represented by the sum of a few Gaussian features, loosely referred to as 'clouds', which are similar in absorption to cold clouds but of lower optical depth and which have derived central spin temperatures as high as 300 to 500 K. It is found that both the spin temperatures and the radial velocities of the clouds appear to be related to optical depth.
Dickey John M.
Salpeter Edwin E.
Terzian Ye.
No associations
LandOfFree
Galactic neutral hydrogen emission-absorption observations from Arecibo 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 Galactic neutral hydrogen emission-absorption observations from Arecibo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Galactic neutral hydrogen emission-absorption observations from Arecibo will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-943653