An X-ray look at the Seyfert 1 Galaxy Mrk 590: XMM-Newton and Chandra reveal complexity in circumnuclear gas

LONGINOTTI, A. L.; BIANCHI, S.; SANTOS-LLEÓ, M.; RODRÍGUEZ-PASCUAL, P.; GUAINAZZI, M.; CARDACI, M.; POLLOCK, A. M. T.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Año: 2007 vol. 470 p. 73 - 81

0004-6361

Context. This paper reports on a partially simultaneous observation of the bright Seyfert 1 Galaxy Mrk 590, performed by XMM-Newton and Chandra. Aims. The long exposure (~100 ks) allows us to investigate the FeK complex at 6-7 keV and the presence of soft X-ray spectral features in great detail. Methods. We have analysed XMM-Newton data from the European Photon Imaging Camera (EPIC) in the 0.5-12 keV band and from the Reflection Grating Spectrometer (RGS) in the 0.35-2.5 keV band, and data from the High Energy Transmission Gratings (HETGs) onboard Chandra. UV and optical data from the Optical Monitor (OM) onboard XMM-Newton are also included in the analysis. Results. The broad band spectrum is well described by an unabsorbed power law and three unresolved Fe K lines in the 6-7 keV range. The presence of a Compton reflection component and a narrow Fe K line at 6.4 keV is consistent with an origin via torus reflection. The ionised Fe lines at ~6.7 and 7 keV are instead most likely originated by scattering on a warm and ionised gas. The soft X-ray spectrum appears to be almost featureless due to the very bright continuum emission, except for one emission line identified as OVIII Ly alpha detected at ~19 Å by both RGS and Chandra-MEG. The emerging picture consists of an active nucleus seen directly on a "clean" line of sight without intervening material, surrounded by photoionised circumnuclear gas at a high ionisation level. We also study three serendipitous sources in the field of view of Chandra and XMM-Newton. One of these sources may be identified with an ULX of L_{0.3-10 keV} ~ 4 x 10^{40} erg/s.