Detection of Lyman continuum absorption in the BL Lacertae object PKS 0735+178

Abstract

view Abstract Citations (15) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Detection of Lyman continuum absorption in the BL Lacertae object PKS0735+178. Bregman, J. N. ; Glassgold, A. E. ; Huggins, P. J. Abstract The detection of the Lyman edge in the BL Lac object PKS 0735+178 at the absorption red shift determined by optical measurements leads to a lower limit for the column density of atomic hydrogen, N(H I) not less than 4(17)/sq cm. The Lyman-alpha absorption line appears to have been detected, but only an approximate upper limit can be obtained from the data, of the order of 2(19)/sq cm. This amount of atomic hydrogen is less than that for a line of sight through the disk of a normal spiral galaxy. It is suggested that the absorbing material exists either in the halo of a galaxy or in the tenuous, extended, gaseous disk of a galaxy. Publication: The Astrophysical Journal Pub Date: October 1981 DOI: 10.1086/159253 Bibcode: 1981ApJ...249...13B Keywords: Bl Lacertae Objects; Lyman Spectra; Quasars; Ultraviolet Absorption; Absorption Spectra; Gas Density; Hydrogen Atoms; Iue; Red Shift; Astronomy full text sources ADS | data products SIMBAD (1) NED (1) MAST (1)