EDP Sciences
Free access
Volume 427, Number 1, November III 2004
Page(s) 101 - 105
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20041637

A&A 427, 101-105 (2004)
DOI: 10.1051/0004-6361:20041637

XMM-Newton observation of the Seyfert 1.8 ESO 113-G010: Discovery of a highly redshifted iron line at 5.4 keV

D. Porquet1, J. N. Reeves2, 3, P. Uttley2 and T. J. Turner2, 4

1  Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, 85741 Garching, Germany
    e-mail: dporquet@mpe.mpg.de
2  Laboratory for High Energy Astrophysics, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
3  Universities Space Research Association, 7501 Forbes Boulevard, Suite 206, Seabrook, MD 20706, USA
4  Joint Center for Astrophysics, Physics Department, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA

(Received 2 June 2004 / Accepted 17 July 2004 )

We present a spectral analysis of the Seyfert 1.8 ESO 113-G010 observed with XMM-Newton for 4 ks. The spectrum shows a soft excess below 0.7 keV and more interestingly a narrow emission Gaussian line at 5.4 keV (in its rest-frame), most probably originating from a redshifted iron K $\alpha$ line. No significant line at or above 6.4 keV is found contrary to other objects showing redshifted lines, ruling out a strong blue-wing to the line profile. The line is detected at 99% confidence, from performing Monte Carlo simulations which fully account for the range of energies where a narrow iron line is likely to occur. The energy of the line could indicate emission from relativistic (0.17-0.23 c) ejected matter moving away from the observer, as proposed for Mrk 766 by Turner et al. (2004, ApJ, 603, 62). Alternatively, the emission from a narrow annulus at the surface of the accretion disk is unlikely due to the very small inclination angle (i.e. less than 10 $^{\circ}$) required to explain the narrow, redshifted line in this intermediate Seyfert galaxy. However emission from a small, localized hot-spot on the disk, occurring within a fraction of a complete disk orbit, could also explain the redshifted line. This scenario would be directly testable in a longer observation, as one would see significant variations in the energy and intensity of the line within an orbital timescale.

Key words: galaxies: active -- galaxies: quasars: general -- X-rays: general -- line: formation -- X-rays: individual: ESO 113-G010

SIMBAD Objects

© ESO 2004