Multiwavelength campaign on Mrk 509

III. The 600 ks RGS spectrum: unravelling the inner region of an AGN

¹ SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
e-mail: r.g.detmers@sron.nl
² Astronomical Institute, University of Utrecht, Postbus 80000, 3508 TA Utrecht, The Netherlands
³ Instituto de Astronomía, Universidad Católica del Norte, Avenida Angamos 0610, Casilla 1280, Antofagasta, Chile
⁴ Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH, UK
⁵ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
⁶ Department of Physics & Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA
⁷ Department of Physics, Virginia Tech, Blacksburg, VA 24061, USA
⁸ Department of Physics, Technion, Haifa 32000, Israel
⁹ Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK
¹⁰ Dipartimento di Fisica, Universita degli Studi Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
¹¹ INAF – IASF Bologna, via Gobetti 101, 40129 Bologna, Italy
¹² UJF-Grenoble 1/CNRS-INSU, Institut de Plantologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, 38041 Grenoble, France
¹³ School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ, UK

Received: 16 March 2011
Accepted: 16 May 2011

Abstract

We present the results of our 600 ks RGS observation as part of the multiwavelength campaign on Mrk 509. The very high quality of the spectrum allows us to investigate the ionized outflow with an unprecedented accuracy due to the long exposure and the use of the RGS multipointing mode. We detect multiple absorption lines from the interstellar medium and from the ionized absorber in Mrk 509. A number of emission components are also detected, including broad emission lines consistent with an origin in the broad line region, the narrow O vii forbidden emission line and also (narrow) radiative recombination continua. The ionized absorber consists of two velocity components (v = −13 ± 11 km s^-1 and v = −319 ± 14 km s^-1), which both are consistent with earlier results, including UV data. There is another tentative component outflowing at high velocity, −770 ± 109 km s^-1, which is only seen in a few highly ionized absorption lines. The outflow shows discrete ionization components, spanning four orders of magnitude in ionization parameter. Due to the excellent statistics of our spectrum, we demonstrate for the first time that the outflow in Mrk 509 in the important range of log ξ between 1−3 cannot be described by a smooth, continuous absorption measure distribution, but instead shows two strong, discrete peaks. At the highest and lowest ionization parameters we cannot differentiate smooth and discrete components.