X‐Ray Spectral Survey of WGACAT Quasars. II. Optical and Radio Properties of Quasars with Low‐Energy X‐Ray Cutoffs
Open Access
- 1 January 1998
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 492 (1) , 91-97
- https://doi.org/10.1086/305025
Abstract
We have selected quasars with X-ray colors suggestive of a low-energy cutoff, from the ROSAT Position Sensitive Proportional Counter (PSPC) pointed observations archive. We examine the radio and optical properties of these 13 quasars. Five out of the seven quasars with good optical spectra show associated optical absorption lines, with two having high Δv candidate systems. Two other cutoff quasars show reddening associated with the quasar. We conclude that absorption is highly likely to be the cause of the X-ray cutoffs, and that the absorbing material is associated with the quasars, not intervening along the line of sight. The suggestion that gigahertz peaked sources are associated with X-ray cutoffs remains unclear with this expanded sample.Keywords
All Related Versions
This publication has 67 references indexed in Scilit:
- Radio, millimeter-submillimeter, and infrared spectra of flat-spectrum extragalactic radio sourcesThe Astronomical Journal, 1994
- MG II absorption in a sample of 56 steep-spectrum quasarsThe Astrophysical Journal Supplement Series, 1994
- 3C 109: an obscured X-ray luminous quasar?Monthly Notices of the Royal Astronomical Society, 1992
- Is every quasar beamed?The Astrophysical Journal, 1989
- Beaming and the X-ray, optical and radio properties of quasarsMonthly Notices of the Royal Astronomical Society, 1987
- Extended radio emission round core-dominated quasars - constraints on relativistic beaming modelsMonthly Notices of the Royal Astronomical Society, 1986
- Spectropolarimetry and the nature of NGC 1068The Astrophysical Journal, 1985
- 31.4- and 89.6-GHz flux density measurements of extragalactic radio sourcesThe Astronomical Journal, 1981
- Radio Maps of 31 Extragalactic Sources at 2{middle dot}7 and 5{middle dot}0 GHzMonthly Notices of the Royal Astronomical Society, 1972
- The Ohio Survey between +40 and +63 degrees .The Astronomical Journal, 1971