The Nature of the Ultraviolet/X‐Ray Absorber in PG 2302+029

Abstract

We present Chandra X-ray observations of the radio-quiet QSO PG 2302+029. This quasar has a rare system of ultra-high-velocity (À56,000 km s À1 ) UV absorption lines that form in an outflow from the active nucleus. The Chandra data indicate that soft X-ray absorption is also present. We perform a joint UV and X-ray analysis, using photoionization calculations, to determine the nature of the absorbing gas. The UV and X-ray data sets were not obtained simultaneously. Nonetheless, our analysis suggests that the X-ray absorption occurs at high velocities in the same general region as the UV absorber. There are not enough constraints to rule out multizone models. In fact, the distinct broad and narrow UV line profiles clearly indicate that multiple zones are present. Our preferred estimates of the ionization and total column density in the X-ray absorber (log U ¼ 1:6, N H ¼ 10 22:4 cm À2 ) overpredict the O vi 1032, 1038 absorption unless the X-ray absorber is also outflowing at $56,000 km s À1 , but they overpredict the Ne viii 770, 780 absorption at all velocities. If we assume that the X-ray-absorbing gas is outflowing at the same velocity as the UVabsorbing wind and that the wind is radiatively accelerated, then the outflow must be launched at a radius of 10 15 cm from the central continuum source. The smallness of this radius casts doubts on the assumption of radiative acceleration.

Does the X-ray outflow quasar PDS 456 have a UV outflow at 0.3c?

“…Individual outflows can have larger N v/C iv ratios. Measurements in the literature of BALs/mini-BALs at speeds up to nearly 0.2c reveal N v/C iv depth ratios in the range ∼0.5 to 1.5 (Steidel 1990;Jannuzi et al 1996;Hamann et al 1997c,a;Barlow & Sargent 1997;Telfer et al 1998;Sabra et al 2003;Rodríguez Hidalgo 2008;Rodríguez Hidalgo et al 2011Rogerson et al 2016;Moravec et al 2017). Our visual inspections of the 641 outflow quasars in Section 3.4 find crudely ∼2 percent of cases with N v/C iv 2.…”

Evidence of a Strong N [CSC]v[/CSC]/C [CSC]iv[/CSC] Correlation between Emission and Absorption Lines in Active Galactic Nuclei

“…In Elvis (2000), the NALs and BELs are cospatial, situated in gas outflowing from the disk, where NAL gas is the warm highly ionized medium that confines the BEL clouds. In Sabra, Hamann, & Shields (2002), NALs originate from the narrow line-emitting region when the observer is looking down through the line-emitting gas toward the continuum source. It may also be possible that the NAL gas is enriched in the vicinity of the QSO nucleus and then ejected into the host galaxy of the QSO or farther out into the intergalactic medium.…”

Universal spectral shape of high accretion rate AGN

“…Observationally, it is seen through the presence of narrow absorption lines and absorption continua in the soft X-ray band which are well resolved now in the Chandra or XMM data (see The ratio of the total optical depth (absorption plus scattering) to the Thomson optical depth (scattering) as a function of energy for the warm absorber model in Ton S180: ionization parameter at the surface ξ = 10 5 , incident flux with photon index 2.6 extending from 12 eV to 100 keV, density profile from the constant pressure condition, total column density 1.1 × 10 23 cm −2 (solid line) and 8 × 10 22 cm −2 (dashed line). Kaastra et al 2002;Lee et al 2001;Steenbrugge et al 2003;Sabra et al 2003). Most lines come from highly ionized species like CIV, OVII and OVIII, suggesting that the temperature of the medium is of the order of 10 5 −10 6 K. The column density of the warm absorber is frequently of the order of 10 23 cm −2 or more, and the medium is extended but probably clumpy (see e.g.…”