Iron line spectroscopy of NGC 4593 with XMM-Newton: where is the black hole accretion disc?
Abstract
We present an analysis of the 2-10 keV XMM-Newton/EPIC-pn spectrum of the Seyfert-1 galaxy NGC 4593. Apart from the presence of two narrow emission lines corresponding to the Kα lines of cold and hydrogen-like iron, this spectrum possesses a power-law form to within ~3-5 per cent. There is a marked lack of spectral features from the relativistic regions of the black hole accretion disc. We show that the data are, however, consistent with the presence of a radiatively efficient accretion disc extending right down to the radius of marginal stability if it possesses low iron abundance, an appropriately ionized surface, a very high inclination, or a very centrally concentrated emission pattern (as has been observed during the deep minimum state of the Seyfert galaxy MCG-6-30-15). Deeper observations of this source are required in order to validate or reject these models.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2004
- DOI:
- 10.1111/j.1365-2966.2004.07909.x
- arXiv:
- arXiv:astro-ph/0404187
- Bibcode:
- 2004MNRAS.352..205R
- Keywords:
-
- accretion;
- accretion discs;
- black hole physics;
- galaxies: individual: NGC 4593;
- galaxies: Seyfert;
- Astrophysics
- E-Print:
- 6 pages, 3 postscript figures. Accepted for publication in the Monthly Notices of the Royal Astronomical Society