相关论文: Long time-scale variability in GRS1915+105

Accretion onto black holes often proceeds via an accretion disk or a temporary disk-like pattern. Variability features observed in light curves as well as theoretical models of accretion flows suggest that accretion disks tend to be…

We present a comprehensive study of GRS 1915+105 in wide energy band ($0.5-60$ keV) using AstroSat observations during the period of $2016-2019$. The MAXI X-ray lightcurve of the source shows rise and decay profiles similar to canonical…

We have constructed self-similar models of a time-dependent accretion disk in both sub and super-Eddington phases with wind outflows for tidal disruption events (TDEs). The physical input parameters are the black hole (BH) mass…

Eccentric white dwarf-massive black hole binaries can potentially source some extreme X-ray transients, including the recently observed quasi-periodic X-ray eruptions and tidal disruption events at the galactic nuclei. Meanwhile, they are…

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…

Black hole binaries are variable in timescales of rang from months to milli-seconds. The origin of this variability is still not clear, it could be due to the variation of external parameters, like mass accretion rate, instabilities in the…

Black hole X-ray binaries (BHXBs) show rich phenomenology in the spectral and timing properties. We collected the spectral data of 20 BHXBs from the literature across different spectral states. The spectral properties are studied in the…

We present a model of an outburst of the soft X-ray transient A0620-003. A two-dimensional time-dependent smoothed particle hydrodynamics scheme is used to simulate the evolution of the accretion disc through a complete outburst. The scheme…

The Galactic black hole transient GRS1915+105 is famous for its markedly variable X-ray and radio behaviour, and for being the archetypal galactic source of relativistic jets. It entered an X-ray outburst in 1992 and has been active ever…

It is commonly believed that accretion discs are truncated and their inner regions are described by advection dominated accretion flows (ADAFs) in the hard spectral state of black hole X-ray binaries. However, the increasing occurrence of a…

Irradiation of the accretion disc causes reflection signatures in the observed X-ray spectrum, encoding important information about the disc structure and density. A Type I X-ray burst will strongly irradiate the accretion disc and alter…

Cataclysmic variable stars are in many ways similar to X-ray binaries. Both types of systems possess an accretion disk, which in most cases can reach the surface (or event horizon) of the central compact object. The main difference is that…

A phenomenological model of X-ray variability of accreting black holes is considered, where the variable emission is attributed to multiple active regions/perturbations moving radially towards the central black hole. The hard X-rays are…

We perform simulations of magnetohydrodynamic accretion onto equal-mass, nonspinning binary black holes in 3+1 full general relativity addressing the effects of orbital eccentricity. We find that binary black holes with non-negligible…

We present 3D numerical simulations of the early evolution of long-duration gamma-ray bursts in the collapsar scenario. Starting from the core-collapse of a realistic progenitor model, we follow the formation and evolution of a central…

I briefly review the theory of soft X-ray transient systems. Irradiation of the accretion disc faces by the central X-ray source determines both the occurrence and the nature of the outbursts, in particular forcing these to be long viscous…

We present new X-ray, optical, and UV observations of the tidal disruption event candidate eRASSt J234402.9-352640, (hereafter J2344). Between 50 and 60 days after peak optical brightness, J2344 exhibited large-amplitude modulations in its…

Using archival RXTE data, we show that the ultracompact X-ray binary in NGC 1851 exhibits large amplitude X-ray flux varations of more than a factor of 10 on timescales of days to weeks and undergoes sustained periods of months where the…

Due to the non-axisymmetric potential of the central bar, barred spiral galaxies form, in addition to their characteristic arms and bar, a variety of structures within the thin gas disk, like nuclear rings, inner spirals and dust-lanes.…

Black hole and neutron star accretion flows display unusually high levels of hard coronal emission in comparison to all other optically thick, gravitationally bound, turbulent astrophysical systems. Since these flows sit in deep…