Browsing Faculty of Arts and Sciences by Keyword "X Ray Astronomy"

Now showing items 1-6 of 6

    • Absorption in X-ray spectra of high-redshift quasars 

      Elvis, Martin S.; Fiore, Fabrizio; Wilkes, Belinda Jane; McDowell, Jonathan Christopher; Bechtold, Jill (IOP Publishing, 1994)
      We present evidence that X-ray absorption is common in high-redshift quasars. We have studied six high-redshift (z approximately 3) quasars with the ROSAT Position Sensitive Proportional Counter (PSPC) of which four are ...

    • Infrared to x-ray spectral energy distributions of high redshift quasars 

      Bechtold, Jill; Elvis, Martin S.; Fiore, Fabrizio; Kuhn, Olga; Cutri, Roc M.; McDowell, Jonathan Christopher; Rieke, Marcia; Siemiginowska, Aneta L.; Wilkes, Belinda Jane (IOP Publishing, 1994)
      We have observed 14 quasars with z greater than 2.8 with the ROSAT-PSPC, and detected 12 of them, including the z=4.11 quasar 0000-263. We present the first x-ray spectrum of a radio quiet quasar with z greater than 3, ...

    • Multifrequency observations of KAZ 102 during the ROSAT all-sky survey 

      Treves, A.; Fink, H. H.; Malkan, M.; Wagner, S. J.; Wilkes, Belinda Jane; Baganoff, F.; Heidt, J.; Pian, E.; Sadun, A.; Schaeidt, S.; Bonnell, J. T.; Brinkmann, W.; de Martino, D.; Maraschi, L.; Tanzi, E. G.; Ulrich, M. H.; Wamsteker, W. (IOP Publishing, 1995)
      The bright quasar Kaz 102, which lies in the vicinity of the North Ecliptic Pole, was monitored during the ROSAT All Sky Survey for 121.5 days from 1990 July 30 to 1991 January 25. In the course of the survey, optical ...

    • The soft x-ray properties of a complete sample of optically selected quasars. 1: First results 

      Laor, Ari; Fiore, Fabrizio; Elvis, Martin S.; Wilkes, Belinda Jane; McDowell, Jonathan Christopher (IOP Publishing, 1994)
      We present the results of ROSAT position sensitive proportional counter (PSPC) observations of 10 quasars. These objects are part of our ROSAT program to observe a complete sample of optically selected quasars. This sample ...

    • X-ray absorption toward the red quasar 3C 212 

      Elvis, Martin S.; Fiore, Fabrizio; Mathur, Smita; Wilkes, Belinda Jane (IOP Publishing, 1994)
      A Roentgen Satellite (ROSAT) X-ray spectrum of the z = 1.049 'red quasar' 3C 212 has a strong low-energy cutoff. The spectrum can be fitted with a power law (of energy index 1.4(+0.8, -0.6) with low-energy photoelectric ...

    • The X-ray and ultraviolet absorbing outflow in 3C 351 

      Mathur, Smita; Wilkes, Belinda Jane; Elvis, Martin S.; Fiore, Fabrizio (IOP Publishing, 1994)
      3C 351 (z = 0.371), and X-ray-'quiet' quasar, is one of the few quasars showing signs of a 'warm absorber' in its X-ray spectrum; i.e., partially ionized absorbing material in the line of sight whose opacity depends on its ...