The soft X-ray spectrum of the luminous narrow line Seyfert galaxy PG1211+143

An XMM-Newton observation of the luminous Seyfert galaxy PG1211+143 in 2001 showed the first evidence for a highly ionised high speed wind (in a non-BAL AGN), with a velocity of v~0.1c based on the identification of blue-shifted absorption lines in both EPIC and RGS spectra. An order-of-magnitude lower velocity was subsequently claimed based on an ion-by-ion model fit to the soft X-ray data. Although repeated observations with XMM-Newton, Chandra and Suzaku confirmed a high velocity, all were based on detection of blue-shifted absorption lines of highly ionised Fe. We show here, in a new analysis of the XMM-Newton RGS data, that the high velocity is indeed present in the soft X-ray spectra, with the higher spectral resolution providing evidence for a second, lower ionisation component close to the systemic velocity of PG1211+143. Variability of the more highly ionised absorption component conforms with that found previously in EPIC spectra in excluding a local origin, while broad emission features are identified with ionised gas at the redshift of the AGN. The RGS spectra also show marginal evidence for lower velocity, lower ionisation absorption which may represent the first detection of a Warm Absorber in PG1211+143; alternatively, the implied redshift would match intrinsic absorption in two dwarf galaxies in the same line of sight.

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Date added: Fri, 11 Oct 13