SIMBAD references

2009ApJ...696..924G - Astrophys. J., 696, 924-940 (2009/May-1)

X-ray insights into the physics of Mini-BAL quasar outflows.


Abstract (from CDS):

We examine the ultraviolet and X-ray properties of 256 radio-quiet Sloan Digital Sky Survey quasars (QSOs) observed in X-rays with Chandra and/or XMM-Newton in order to study the relationship between QSOs with broad C IV absorption lines (BALs; width >2000 km/s) and those with C IV mini-BALs (here defined to have widths of 1000-2000 km/s). Our sample includes 42 BAL and 48 mini-BAL QSOs. The relative X-ray brightness and hard spectral slopes of the mini-BAL population are, on average, intermediate between those of BAL and non-BAL QSOs, as might be expected if narrower and broader absorption line outflows are physically related. However, a significant population of mini-BALs has outflow velocities higher than would be expected for BAL QSOs of the same relative X-ray brightness. Consistently strong X-ray absorption is apparently not required to accelerate at least some mini-BALs to high outflow velocities. Assuming the mini-BAL features are correctly attributed to intrinsic C IV absorption, we suggest that their observed properties may be explained if mini-BALs are "seeds" that can be accelerated to form BALs when sufficient X-ray shielding is present. We also examine several QSOs with broad C IV absorption that have been recently reported to be unusually X-ray bright. Such cases are frequently mini-BAL QSOs, which, as a population, are generally brighter in X-rays than BAL QSOs. Pointed XMM-Newton observations also suggest that these sources (or unresolved neighbors) may have been previously observed in a high-flux state.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: nuclei - quasars: absorption lines - quasars: emission lines - X-rays: general

VizieR on-line data: <Available at CDS (J/ApJ/696/924): table2.dat>

Simbad objects: 262

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