X-ray Spectral Survey of WGACAT Quasars, II: Optical and Radio Properties of Quasars with Low Energy X-ray Cut-offs
نویسندگان
چکیده
We have selected quasars with X-ray colors suggestive of a low energy cutoff, from the ROSAT PSPC pointed 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 ∆v candidate systems. Two other cut-off quasars show reddening associated with the quasar. We conclude that absorption is highly likely to be the cause of the X-ray cut-offs, and that the absorbing material associated with the quasars, not intervening along the line-of-sight. The suggestion that Gigahertz Peaked Sources are associated with X-ray cut-offs remains unclear with this expanded sample. Subject headings: quasars — absorption, X-rays
منابع مشابه
X-ray Spectral Survey of WGACAT Quasars, I: Spectral Evolution & Low Energy Cut-offs
We have used the WGA catalog of ROSAT PSPC X-ray sources to study the X-ray spectrum of about 500 quasars in the redshift interval 0.1–4.1, detected with a signal to noise better than 7. We have parameterized the PSPC spectrum in terms of two ‘effective energy spectral indices’, αS (0.1-0.8 keV), and αH (0.42.4 keV), which allows for the different Galactic NH along the quasars line of sight. We...
متن کاملTHE DEEP X-RAY RADIO BLAZAR SURVEY (DXRBS) II. New Identifications
We have searched the archived, pointed ROSAT Position Sensitive Proportional Counter data for blazars by correlating the WGACAT X-ray database with several publicly available radio catalogs, restricting our candidate list to serendipitous X-ray sources with a flat radio spectrum (αr ≤ 0.70, where Sν ∝ ν −α). This makes up the Deep X-ray Radio Blazar Survey (DXRBS). Here we present new identific...
متن کاملAn X–ray selected sample of radio–loud quasars
We construct the first X-ray selected sample of broad line radio-loud AGN from the EMSS survey. In order to test unifying schemes for radio-loud objects, their spectral and statistical properties (both flat and steep spectrum objects) are examined and compared with those of other samples of blazars. The X–ray selection allows us to explore properties of radio–loud quasars 10–100 weaker in the r...
متن کاملThe X-ray Properties of the Most-luminous Quasars from the Sloan Digital Sky Survey
Utilizing 21 new Chandra observations as well as archival Chandra, ROSAT, and XMM-Newton data, we study the X-ray properties of a representative sample of 59 of the most optically luminous quasars in the Universe (Mi ≈ −29.3 to −30.2) spanning a redshift range of z ≈ 1.5–4.5. Our full sample consists of 32 quasars from the Sloan Digital Sky Survey (SDSS) Data Release 3 (DR3) quasar catalog, two...
متن کاملThe soft X-ray properties of quasars in the Sloan Digital Sky Survey
We use the ROSAT All Sky Survey (RASS) to study the soft X-ray properties of a homogeneous sample of 46,420 quasars selected from the third data release of the Sloan Digital Sky Survey (SDSS). Optical luminosities, both at rest-frame 2500Å (L2500) and in [OIII] (L[OIII]) span more than three orders of magnitude, while redshifts range over 0.1 < z < 5.4. We detect 3366 quasars directly in the ob...
متن کامل