Optical Identification of Quasar 0917+7122 in the Direction of an\n Extreme-Ultraviolet Source

1995/09/21 by Dan Maoz, Eran Ofek, E. O. Ofek +21
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #astro-ph

paper · pdf · doi:10.48550/arxiv.astro-ph/9509120

9 pages, compressed, uuencoded postscript, including figures. Accepted by A&A (Research Note)

arxiv created 1995/09/21 · openalex publication_date 1995/09/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We report the optical identification of an R=18.3 mag, z=2.432 quasar at\nthe position of a 6 cm radio source and a faint rosat PSPC X-ray source. The\nquasar lies within the error circles of unidentified extreme-UV (EUV)\ndetections by the euve and rosat WFC all-sky surveys at \∼ 400 AA and\n\∼ 150 AA, respectively. A 21 cm H I emission measurement in the direction\nof the quasar with a 21'-diameter beam yields a total H I column density of\nN_H=3.3\× 10²⁰ cm^-2, two orders of magnitude higher than the\nmaximum allowed for transparency through the Galaxy in the EUV. The source of\nthe EUV flux is therefore probably nearby ( ltorder 100 pc), and unrelated to\nthe quasar.\n

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