Open AccessIron line spectroscopy of NGC 4593 with XMM–Newton : where is the black hole accretion disc?
Author(s) -
Reynolds Christopher S.,
Brenneman Laura W.,
Wilms Jörn,
Kaiser Mary Elizabeth
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07909.x
Subject(s) - physics , astrophysics , accretion (finance) , galaxy , accretion disc , radius , emission spectrum , spectral line , line (geometry) , ionization , black hole (networking) , epic , spectroscopy , astronomy , geometry , ion , computer network , art , routing protocol , computer security , mathematics , routing (electronic design automation) , literature , quantum mechanics , computer science , link state routing protocol
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.