We performed detailed calculations of the relativistic effects acting on both the reflection continuum and the iron line from accretion discs around rotating black holes. Fully relativistic transfer of both illuminating and reprocessed photons has been considered in Kerr spacetime. We calculated overall spectra, line profiles and integral quantities, and present their dependences on the black h...

The observed profile of spectral lines from a relativistic accretion disk can constrain parameters such as the disk geometry and the rotation of the central black hole. The formation of the spectral line in a disk generally has been modeled with simple assumptions such as local isotropy of emission. Here we consider line formation in the presence of velocity gradients induced by the differentia...

abstract the spontaneous emission spectrum from a driven three-level atom placed inside a double-band photonic crystal has been investigated. we use the model which assumes the upper levels of the atomic transition are coupled via a classical driving field. the transition from one of the upper levels to lower level couples to the modes of the modified reservoir, and the transition from the othe...

We observed the Galactic black hole GX 339−4 with the Chandra High Energy Transmission Grating Spectrometer (HETGS) for 75 ksec during the decline of its 2002–2003 outburst. The sensitivity of this observation provides an unprecedented glimpse of a Galactic black hole at about a tenth of the luminosity of the outburst peak. The continuum spectrum is well described by a model consisting of multi...

The fluorescent iron Kα line is a powerful observational probe of the inner regions of black holes accretion disks. Previous studies have assumed that only material outside the radius of marginal stability (r = 6m for a Schwarzschild hole) can contribute to the observed line emission. Here, we show that fluorescence by material inside the radius of marginal stability, which is in the process of...

Barley grain at maturity can have yellow, purple, blue, and black pigmentations which are suggested to play a protective role under stress conditions. The first three types of the colors are caused by phenolic compounds flavonoids; the last one is caused by phytomelanins, oxidized and polymerized phenolic compounds. Although the genetic basis of the flavonoid biosynthesis pathway in barley has ...

The sizes of the broad-line regions (BLRs) in γ-ray active galactic nuclei (AGNs) are estimated from their optical continuum luminosity by using the empirical relation between RBLR and Lλ,opt. Using the broad emission line data, we derive the photon energy density in the relativistic blobs near the massive black holes in AGNs. We calculate the power of the broad-line photons Compton up-scattere...

The mass of massive black holes in quasar cores can be deduced using the typical velocities of Hβ-emitting clouds in the Broad Line Region (BLR) and the size of this region. However, this estimate depends on various assumptions and is susceptible to large systematic errors. The Hβ-deduced black hole mass in a sample of 14 bright quasars is found here to correlate with the quasar host galaxy lum...

We report on a deep Suzaku observation of the stellar-mass black hole GX 339−4 in outburst. A clear, strong, relativistically-shaped iron emission line from the inner accretion disk is observed. The broad-band disk reflection spectrum revealed is one of the most sensitive yet obtained from an accreting black hole. We fit the Suzaku spectra with a physically–motivated disk reflection model, blur...

We report the detection of a statistically significant flare-like event in the Mg ii λ2800 emission line of 3C 454.3 during the outburst of autumn 2010. The highest levels of emission line flux recorded over the monitoring period (2008–2011) coincide with a superluminal jet component traversing through the radio core. This finding crucially links the broad emission line fluctuations to the non-...