XMM-Newton observations of warm absorbers in PG quasars

Abstract

We present XMM-Newton European Photon Imaging Camera observations of warm absorbers in the quasars PG 1114+445 and PG 1309+355, both of which exhibit evidence for absorption by warm material in the line of sight. We find the absorption in PG 1114+445 to be in two phases, a `hot' phase with a log ionization parameter, ξ, of 2.57, and a `cooler' phase with logξ= 0.83; an unresolved transition array (UTA) of M-shell iron is observed in the cooler phase. The absorption in this quasar is similar to that observed in the Seyfert1 NGC 3783. The absorption in PG 1309+355 consists of a single phase, with logξ= 1.87. The absorbing gas lies at distances of 10¹⁸-10²² cm from the continuum radiation sources in these active galactic nuclei (AGN), which suggests that it could originate in a wind emanating from a molecular torus. We derive distances assuming that these X-ray warm absorbers have the same velocity as the ultraviolet warm absorbers observed in these quasars. The distances to the warm absorbers from the central continuum source scale approximately with the square root of the AGN ionizing luminosity, a result consistent with the warm absorber originating as a torus wind. The kinetic luminosities of these outflowing absorbers represent insignificant fractions (<10^-3) of the energy budgets of the AGN.