BAL outflow contribution to AGN feedback: frequency of S IV outflows in the SDSS

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IOP Publishing Ltd.

We present a study of broad absorption line (BAL) quasar outflows that show S IV lambda 1063 and S IV* lambda 1073 troughs. The fractional abundances of S IV and C IV peak at similar value of the ionization parameter, implying that they arise from the same physical component of the outflow. Detection of the S IV* troughs will allow us to determine the distance to this gas with higher resolution and higher signal-to-noise spectra, therefore providing the distance and energetics of the ubiquitous C IV BAL outflows. In our bright sample of 156 SDSS quasars, 14% show C IV and 1.9% S IV troughs, which are consistent with a fainter magnitude sample with twice as many objects. One object in the fainter sample shows evidence of a broad S IV trough without any significant trough present from the excited state line, which implies that this outflow could be at a distance of several kpc. Given the fractions of C IV and S IV, we establish firm limits on the global covering factor on S IV that ranges from 2.8% to 21% (allowing for the k-correction). Comparison of the expected optical depth for these ions with their detected percentage suggests that these species arise from common outflows with a covering factor closer to the latter.

quasars: absorption lines, broad absorption-line, digital sky survey, large telescope observations, hubble-space-telescope, quasi-stellar objects, lyman-alpha forest, intrinsic absorption, physical conditions, active galaxies, qso, 2359-1241
Jay P. Dunn et al. 2012. "BAL outflow contribution to AGN feedback: frequency of S IV outflows in the SDSS," ApJ 750 143 doi:10.1088/0004-637X/750/2/143