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

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 (similar to 100 ks) allows us to investigate the Fe K 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 similar to 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 similar to 19 angstrom 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 L0.3-10 keV similar to 4 x 10(40) erg/s.