Browsing by Keyword "quasars"

Now showing items 1-5 of 5

    • The diversity of soft X-ray spectra in quasars 

      Elvis, Martin S.; Wilkes, Belinda Jane; Tananbaum, Harvey D. (IOP Publishing, 1985)
      Soft X-ray spectra for three quasars obtained with the Einstein Imaging Proportional Counter covering the 0.1-4.0 keV band are reported. Power-law fits to these spectra have best-fit energy indices of 1.2 +0.6 or -0.2, for ...

    • Persistence and change in the soft X-ray spectrum of the quasar PG 1211 + 143 

      Elvis, Martin S.; Wilkes, Belinda Jane; Giommi, P.; McDowell, Jonathan Christopher (IOP Publishing, 1991)
      The present study examines two Einstein and three Exosat observations of PG 1211 + 143 over a 6-yr baseline which show that strong steep-spectrum low-energy X-ray emission is a persistent feature of this quasar. Exosat ...

    • PG0946 + 301 - A low-redshift, broad absorption line QSO 

      Wilkes, Belinda Jane (IOP Publishing, 1985)
      The discovery of a new broad absorption line (BAL) QSO with the lowest emisson-line redshift to date (z = 1.216) is reported. The data provide evidence for complex broad absorption up to velocities ≡14,500 km s-1 relative ...

    • The soft X-ray excess in Einstein quasar spectra 

      Masnou, J.; Wilkes, Belinda Jane; Elvis, Martin S.; McDowell, Jonathan Christopher; Arnaud, K. (1991)
      An SNR-limited subsample of 14 quasars from the Wilkes and Elvis (1987) sample is presently investigated for low-energy excess above a high-energy power law in the X-ray spectra obtained by the Einstein Imaging Proportional ...

    • X-ray spectra of compact extragalactic radio sources 

      Worrall, Diana M.; Wilkes, Belinda Jane (IOP Publishing, 1990)
      A comparison is conducted of the 0.1-3.5 keV mean power law energy spectral indices (alpha) measured by the Einstein Observatory IPC for (1) 19 low polarization, flat radio spectrum (FRS) core-dominant QSOs; (2) 12 highly ...