The X-ray properties of the optically brightest mini-BAL quasars from the Sloan Digital Sky Survey

Jianfeng Wu, W. N. Brandt, M. L. Comins, Robert R. Gibson, Ohad Shemmer, Gordon P. Garmire, Donald P. Schneider

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


We have compiled a sample of 14 of the optically brightest radio-quiet quasars (mi ≤ 17.5 and z ≥1.9) in the Sloan Digital Sky Survey Data Release 5 quasar catalog that have C IV mini-broad absorption lines (mini-BALs) present in their spectra. X-ray data for 12 of the objects were obtained via a Chandra snapshot survey using ACIS-S, while data for the other two quasars were obtained from archival XMM-Newton observations. Joint X-ray spectral analysis shows that the mini-BAL quasars have a similar average power-law photon index (Γ ≈ 1.9) and level of intrinsic absorption (Nh ≤ 8 × 1021 cm-2) as non-BMB (neither BAL nor mini-BAL) quasars. Mini-BAL quasars are more similar to non-BMB quasars than to BAL quasars in their distribution of relative X-ray brightness (assessed with Δαox). Relative colors indicate mild dust reddening in the optical spectra of mini-BAL quasars. Significant correlations between Δαox and UV absorption properties are confirmed for a sample of 56 sources combining mini-BAL and BAL quasars with high signal-to-noise ratio rest-frame UV spectra, which generally supports models in which X-ray absorption is important in enabling driving of the UV absorption-line wind. We also propose alternative parameterizations of the UV absorption properties of mini-BAL and BAL quasars, which may better describe the broad absorption troughs in some respects.

Original languageEnglish (US)
Pages (from-to)762-778
Number of pages17
JournalAstrophysical Journal
Issue number1
StatePublished - Nov 20 2010

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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