Related papers: Time-Dependent Disk Models for the Microquasar GRS…
We present evidence for cosmological gas accretion onto spiral galaxies in the local universe. The accretion is seen through its effects on the dynamics of the extra-planar neutral gas. The accretion rates that we estimate for two nearby…
[abridged] We present a 1+1D global magnetically-driven disk accretion model that captures the essence of the MRI-driven accretion, without resorting to 3D global non-ideal MHD simulations. The gas dynamics is assumed to be solely…
We present the first detailed phase-resolved spectral analysis of a joint Chandra High Energy Transmission Grating Spectrometer and Rossi X-ray Timing Explorer observation of the rho variability class in the microquasar GRS 1915+105. The…
The non-linear fluid dynamics of a warped accretion disc was investigated in an earlier paper by developing a theory of fully non-linear bending waves in a thin, viscous disc. That analysis is here extended to take proper account of thermal…
We present the results from simultaneous Chandra HETGS and RXTE observations of the microquasar GRS 1915+105 in its quasi-stable "soft state" (or State A) performed on 2007 August 14, several days after the state transition from "hard…
We explore conditions and structure of accretion disks in short-period Cata- clysmic Variables (CVs), which have evolved beyond the period minimum. We show that accretion discs in systems with extreme mass ratios grow up to the size of…
Accretion disks in AGN should be subject to the same type of instability as in cataclysmic variables (CVs) or in low-mass X-ray binaries (LMXBs), which leads to dwarf nova and soft X-ray transient outbursts. It has been suggested that this…
Observations of protoplanetary disks show that some characteristics seem recurrent, even in star formation regions that are physically distant such as surface mass density profiles varying as $r^{-1}$, or aspect ratios about 0.03 to 0.23.…
We present a non-linear numerical model for a geometrically thin accretion disk with the addition of stochastic non-linear fluctuations in the viscous parameter. These numerical realizations attempt to study the stochastic effects on the…
Near-maximally spinning black holes display conformal symmetry in their near-horizon region, which is therefore the locus of critical phenomena. In this paper, we revisit the Novikov-Thorne accretion thin disk model and find a new…
A growing number of debris discs have been detected around metal-polluted white dwarfs. They are thought to be originated from tidally disrupted exoplanetary bodies and responsible for metal accretion onto host WDs. To explain (1) the…
We show that the time delay between the optical and X-ray outbursts of the black-hole soft X-ray transient source GRO J1655-40, observed in April 1996, requires that the accretion flow in this object must consist of two components: a cold…
X-ray observations of Seyfert 1 galaxies offer the unique possibility of observing spectral variability on timescales comparable to the dynamical time of the inner accretion flow. They typically show highly variable lightcurves, with Power…
We use the standard Runge-Kutta method to solve the set of basic equations describing black hole accretion flows composed of two-temperature plasma. We do not invoke any extra energy transport mechanism such as thermal conduction and do not…
We address the task of modeling soft X-ray and optical light curves of X-ray novae in the high/soft state. The analytic model of viscous evolution of an externally truncated accretion \alpha-disk is used. Relativistic effects near a Kerr…
We present very high resolution hydrodynamical simulations of accretion discs in black hole X-ray binaries accreting near the Eddington limit. The results show that mass loss, irradiation and tidal interactions all have a profound effect on…
We analyze a set of three RXTE Target of Opportunity observations of the Galactic microquasar GRS 1915+105, observed on April 2000, during a multi-wavelength campaign. During the three observations, a strong, variable low frequency (2-9 Hz)…
The microquasar GRS 1915+105, exhibits a large variety of characteristic states, according to its luminosity, spectral state, and variability. The most interesting one is the so-called rho-state, whose light curve shows recurrent bursts.…
We develop a model of time delays between the continuum bands in the Narrow Line Seyfert 1 galaxy Mrk 335 to explain the observed delays measured in this source. We consider two geometries: an accretion disk with fully ionized warm absorber…
We investigate the association between the accretion disk during radio plateau state and the following superluminal relativistic radio jets with peak intensity varies from 200 mJy to 1000 mJy observed over a period of five years and present…