相关论文: Iron Line Profiles in Strong Gravity
In spectra of many Seyfert galaxies there is a wide emission line of Fe $K_\alpha$. The line profile with two maxima supposes that the line emerges in innermost regions of an accretion disk around a black hole, hence, it is necessary to…
X-ray reflection from an accretion disc produces characteristic emission lines allowing us to probe the innermost regions in AGN. We investigate these emission lines under a framework of Riemannian geometrical optics where the corona has a…
Based on a new estimation of their thickness, the global properties of relativistic slim accretion disks are investigated in this work. The resulting emergent spectra are calculated using the relativistic ray-tracing method, in which we…
The relativistically broadened Fe K$\alpha$ line, originating from the accretion disc in a vicinity of a super massive black hole, is observed in only less than 50\% of type 1 Active Galactic Nuclei (AGN). In this study we investigate could…
Very steep reflection emissivity profiles in the inner part of accretion disks are commonly found in the analysis of X-ray observations of black hole binaries and AGN, but there is some debate about their exact origin. While steep…
The X-ray reflection features of irradiated accretion disks around black holes enable us to probe the effects of strong gravity. We investigate to which precision the reflection signs, i.e. the iron K-line and the Comptonized hump, can be…
We have computed line profiles from self-gravitating toroids around black holes. The specific angular momentum of the toroids is assumed to be constant in space. The images of the toroids show peculiar feature in the rear side of the black…
We report on the iron K-alpha line properties of a sample of Seyfert galaxies observed with the XMM-Newton EPIC pn instrument. Using a systematic and uniform analysis, we find that complexity at iron-K is extremely common in the XMM…
Most of the X-ray emission from luminous accreting black holes emerges from within 20 gravitational radii. The effective emission radius is several times smaller if the black hole is rapidly spinning. General Relativistic effects can then…
(abridged) With most physicists and astrophysicists in agreement that black holes do indeed exist, the focus of astrophysical black hole research has shifted to the detailed properties of these systems. Nature has provided us with an…
Fitting the thermal continuum emission of accreting black holes observed across X-ray bands represents one of the principle means of constraining the properties (mass and spin) of astrophysical black holes. Recent ''continuum fitting''…
We discuss three applications of a gauge theory of gravity to rotating astrophysical systems. The theory employs gauge fields in a flat Minkowski background spacetime to describe gravitational interactions. The iron fluorescence line…
Quasars show a remarkable degree of atomic emission line-broadening, an observational feature which, in conjunction with a radial distance estimate for this emission from the nucleus is often used to infer the mass of the central…
In this work we show that Bardeen-Petterson accretion disks can exhibit unique, detectable features in relativistically broadened emission line profiles. Some of the unique characteristics include inverted line profiles with sharper red…
Accretion disk reflection spectra, including broad iron emission lines, bear the imprints of the strong Doppler shifts and gravitational red-shifts close to black holes. The extremity of these shifts depends on the proximity of the…
The spacetime geometry around astrophysical black holes is well approximated by the Kerr metric, but deviations from standard predictions are possible in a number of scenarios beyond Einstein's gravity and in the presence of exotic matter.…
We prescribe a method to study the effects of self-gravity of accretion disk around a black hole associated with long Gamma Ray Bursts (GRBs) in an evolving background Kerr metric. This is an extension to our previous work where we…
The inner parts of black-hole accretion discs shine in X-rays which can be monitored and the observed spectra can be used to trace strong gravitational fields in the place of emission and along paths of light rays. This paper summarizes…
Relativistic Fe K emission lines from accretion disks and from disk winds encode key information about black holes, and their accretion and feedback mechanisms. We show that these two processes can in principle produce indistinguishable…
Continuum spectrum emitted by the accretion disk around quasars hold a wealth of information regarding the strong gravitational field produced by the massive central object. Such strong gravity regime is often expected to exhibit deviations…