Browsing FAS Scholarly Articles by Keyword "Absorption Spectra"

Now showing items 1-5 of 5

    • 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 ...

    • The complex optical to soft x-ray spectrum of the low-redshift radio-quiet quasars 

      Fiore, Fabrizio; Elvis, Martin S.; McDowell, Jonathan Christopher; Siemiginowska, Aneta L.; Wilkes, Belinda Jane (IOP Publishing, 1994)
      Eight high signal-to-noise ROSAT Position Sensitive Proportional Counter (PSPC) observations of six low-redshift (o.048 less than z less than 0.155) radio-quiet quasars have been analyzed to study ant soft excess. All the ...

    • Damped Lyman-alpha absorption by disk galaxies with large redshifts. III - Intermediate-resolution spectroscopy 

      Turnshek, David A.; Wolfe, Arthur M.; Lanzetta, Kenneth M.; Briggs, Frank H.; Cohen, Ross D.; Foltz, Craig B.; Smith, Harding E.; Wilkes, Belinda Jane (IOP Publishing, 1989)
      New intermediate-resolution spectroscopy for six members of a sample of 68 moderate- to high-redshift QSOs is presented. Evidence is reported which indicates that seven strong absorption features in the QSO spectra are due ...

    • PKS 0483-436 - A high-redshift quasar with strong X-ray absorption 

      Wilkes, Belinda Jane; Elvis, Martin S.; Fiore, Fabrizio; McDowell, Jonathan Christopher; Tananbaum, Harvey D.; Lawrence, Andrew (IOP Publishing, 1992)
      The first X-ray spectrum of a high-redshift (z = 2.85) quasar is reported. The Rosat PSPC spectrum of PKS 0438-436, covering 0.3-9 keV in the quasar's rest frame, reveals unexpected absorption of about 1 x 10 exp 22/sq cm, ...

    • 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 ...