Estimate of the black-hole mass in NGC 6814 from a relativistic accretion disk scenario |
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Authors: | S Campana and L Stella |
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Institution: | (1) Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italia;(2) Osservatorio Astronomico di Brera, Via Brera 28, 20121 Milano, Italia |
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Abstract: | Summary By using a fully relativistic model for the spectral line produced by a Keplerian disk orbiting a Schwarzschild black hole,
we study the temporal behaviour of the line intensity in response to a continuum variation at an extended central source.
We compare our results with the observed properties of the Seyfert galaxy NGC 6814, whose X-ray flux has been observed to
decrease by a factor of two in ≈ 50 s, while the iron line intensity variations lag continuum variations by 250 s, at the
most. Taking the stationary values of the iron line centroid energy and width, and assuming that the line comes from high-ionisation
stages of iron (as several indications suggest) we derive that the inner radius of the line-emitting region is between 6 and
30r
g
(r
g
=GM/c
2), the inclination is ≤40°, while the mass of the central object is constrained to 8·104
L
43<M<3.9·106
M
⊙(L
43 is the accretion luminosity in units of 1043 erg s−1).
Paper presented at the 6th Cosmic Physics National Conference, Palermo, 3–7 November 1992.
Affiliated to ICRA. |
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Keywords: | X-ray sources |
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