view Abstract Citations (13) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Medium-Resolution Far-Ultraviolet Spectroscopy of PKS 2155-304 Appenzeller, I. ; Mandel, H. ; Krautter, J. ; Bowyer, S. ; Hurwitz, M. ; Grewing, M. ; Kramer, G. ; Kappelmann, N. Abstract Using the Berkeley spectrometer of the Orbiting Retrievable Far and Extreme Ultraviolet Spectrometer (ORFEUS) we observed the 87-117 nm UV spectrum of the BL Lac object PKS 2155 - 304 with about 0.5 A resolution. In addition to the expected interstellar lines we detected higher quantum number counterparts of the intergalactic Lyα lines discovered earlier with IUE and the HST in the direction of PKS 2155-304. The Lyman discontinuities indicate for three of the redshifted clouds a combined H I column density of 2-5 x 10^16^ cm^-2^, while the column density for another cloud appears to be well below 5 x 10^15^ cm^-2^. No significant O VI absorption in the galactic halo toward PKS 2155 - 304 could be detected from our data. Assuming that saturation effects are negligible for these weak features, we obtain for the O VI column density toward PKS 2155-304 a 3 σ upper limit of 2.7 x 10^14^cm^-2^. Publication: The Astrophysical Journal Pub Date: February 1995 DOI: 10.1086/187738 Bibcode: 1995ApJ...439L..33A Keywords: Absorption Spectra; Bl Lacertae Objects; Far Ultraviolet Radiation; Line Spectra; Lyman Alpha Radiation; Ultraviolet Astronomy; Ultraviolet Spectra; Galactic Halos; Intergalactic Media; Interstellar Matter; Oxygen; Red Shift; Spaceborne Astronomy; Ultraviolet Spectroscopy; Astronomy full text sources ADS | data products NED (5) SIMBAD (2) MAST (2)
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