The original idea to show the spacetime geometry using few geodesics was developed by Johnson and Ruffini (1974). We used this idea to interpret the observational data for rotating BH’s. We developed the imitation approach to simulate a propagation of radiation near BH’s. An important problem for this approach is the diagnostics of a black hole metric using X-ray observational data of the iron ...

We present model X-ray spectra of accreting black holes with advection-dominated accretion flows, paying attention to thermal emission lines from the hot plasma. We show that the Advanced X-ray Astrophysical Facility (AXAF) might be able to observe lines from X-ray binaries such as V404 Cyg in quiescence, the Galactic center black hole Sagittarius A, and the nuclei of nearby galaxies such as M8...

There is growing evidence that the distinctive behaviour of the Narrow-line Seyfert 1 (NLS1) galaxies is caused by them being high-mass accretion rate objects, with luminosities close to Eddington. This would make them the high-mass analogues of the soft states seen from Galactic Black holes (GBH). A potential problem with this interpretation is that the Xray emission from NLS1’s is typically h...

Accurately determining the masses of supermassive black holes is crucial to understand their evolution and the establishment of their relationship with their host galaxy properties. Beyond the local universe, the single epoch mass estimation method provides a simple procedure to estimate black hole masses in large spectroscopic samples of type-1 active galactic nuclei. The method assumes virial...

We present black hole mass–bulge velocity dispersion relation for a complete sample of 75 soft X-ray selected AGNs: 43 broad line Seyfert 1s and 32 narrow line Seyfert 1s. We use luminosity and FWHM(Hβ) as surrogates for black hole mass and FWHM([OIII]) as a surrogate for the bulge velocity dispersion. We find that NLS1s lie below the MBH–σ relation of BLS1s, confirming the Mathur et al. (2001)...

We show that a mild derandomization assumption together with the worst-case hardness of NP implies the average-case hardness of a language in non-deterministic quasi-polynomial time. Previously such connections were only known for high classes such as EXP and PSPACE. There has been a long line of research trying to explain our failure in proving worstcase to average-case reductions within NP [F...

A general physical mechanism of the formation of line-driven winds at the vicinity of strong gravitational field sources is investigated in the frame of General Relativity. We argue that gravitational redshifting should be taken into account to model such outflows. The generalization of the Sobolev approximation in the frame of General Relativity is presented. We consider all processes in the m...

We present the results of a recent reverberation-mapping campaign undertaken to improve measurements of the radius of the broad line region and the central black hole mass of the quasar PG2130+099. Cross correlation of the 5100 Å continuum and Hβ emission-line light curves yields a time lag of 22.9 −4.3 days, corresponding to a central black hole mass MBH = (3.8 ± 1.5)×10M⊙. This value supports...

We study the effects of feedback from active galactic nuclei (AGN) on emission from molecular gas in galaxy mergers by combining hydrodynamic simulations which include black holes with a three-dimensional, non-local thermodynamic equilibrium (LTE) radiative transfer code. We find that molecular clouds entrained in AGN winds produce an extended CO morphology with significant off-nuclear emission...

We report [O III] λ5007 Å and [N II] λ6583 Å emission from a globular cluster harboring the ultraluminous X-ray source (ULX) CXOJ033831.8-352604 in the Fornax elliptical galaxy NGC 1399. No accompanying Balmer emission lines are present in the spectrum. One likely possibility is that the forbidden lines emanate from X-ray illuminated debris of a star that has been tidally-disrupted by an interm...