1998/07/31 by T. Yaqoob, I. M. George, T. J. Turner +3 · 4 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/311618
16 pages plus 2 figures. Latex with separate postscript figure files. AASTEX 4.0 macro. Accepted for the Astrophysical Journal Letters
arxiv created 1998/07/31 · openalex publication_date 1998/10/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We report the results from an ASCA observation of the high-luminosity, radio-loud quasar PKS 0637-752 (redshift 0.654), covering the 0.8-15 keV band in the quasar frame. We find the source to have a luminosity of ~10 46 ergs s -1 in the 2-10 keV band, which is a factor of ~3 lower than during a previous Ginga observation. The continuum appears to be well modeled by a simple power law with Γ=1.64±0.07, with no evidence for absorption by material intrinsic to the quasar or Fe-K emission (with an equivalent width ≲80 eV at 90% confidence). However, we do find evidence for a narrow emission line at an energy 1.60±0.07 keV and equivalent width 59 + 38 −34 eV (both in the quasar frame). Line emission at these energies has not been observed in any other active galaxy or quasar to date. We reject the possibility that this line is the result of instrumental artifacts and briefly explore possible identifications.