Related papers: Accretion and Ejection Physics at High Time Resolu…
Accretion of planetary material onto host stars may occur throughout a star's life. Especially prone to accretion, extrasolar planets in short-period orbits, while relatively rare, constitute a significant fraction of the known population,…
In the recent years, the discovery of a new class of Galactic transients with fast and bright flaring X-ray activity, the Supergiant Fast X-ray Transients, has completely changed our view and comprehension of massive X-ray binaries. These…
The discovery and subsequent study of microquasars lead to major progress in our understanding of: 1) the nature of relativistic jets seen elsewhere in the universe, and 2) the connection between the accretion onto compact objects and the…
Young stellar objects in their pre-main sequence phase are characterized by irregular changes in brightness, generally attributed to an increase of the mass accretion rate due to various kind of instabilities occurring in the circumstellar…
High-mass X-ray binaries are fundamental in the study of stellar evolution, nucleosynthesis, structure and evolution of galaxies and accretion processes. Hard X-rays observations by INTEGRAL and Swift have broad- ened significantly our…
We describe astrophysical processes around a black hole keeping primarily the physics of accretion in mind. In Section 1, we briefly discuss the formation, evolution and detection of black holes. We also discuss the difference of flow…
The spectrum of the hard X-ray background records the history of accretion processes integrated over the cosmic time. Several observational and theoretical evidences indicate that a significant fraction of the energy density is obscured by…
We review some of the possible models that are able to describe the current Universe which point out the future singularities that could appear. We show that the study of the dark energy accretion onto black- and worm-holes phenomena in…
Relativistic outflows are common in accreting and forming black holes. Despite the enormous differences in scale, stellar-mass black holes in X-ray binaries and supermassive black holes in Galactic Nuclei produce jets with analogous…
In recent years, much effort has been devoted to unraveling the connection between the accretion flow and the jets in accreting compact objects. In the present work, we report new constraints on these issues, through the long term study of…
Ultraluminous X-ray sources (ULXs) represent an extreme class of accreting compact objects: from the identification of some of the accretors as neutron stars to the detection of powerful winds travelling at 0.1-0.2 c, the increasing…
We compute mass outflow rates from advective accretion disks around compact objects, such as neutron stars and black holes. These computations, for the first time, are done using combinations of exact transonic inflow and outflow solutions…
Accreting black holes and neutron stars in their hard (low) state show not only very similar X/gamma-ray spectra but also that the behaviour of their light curves is quite similar which can be quantified as having similar power-density…
The mechanism by which outflows and plausible jets are driven from black hole systems, still remains observationally elusive. Notwithstanding, several observational evidences and deeper theoretical insights reveal that accretion and…
Accreting neutron stars in low-mass X-ray binaries show outflows -- and sometimes jets -- in the general manner of accreting black holes. However, the quantitative link between the accretion flow (traced by X-rays) and outflows and/or jets…
We study effects of high-energy particles on the accretion flows onto a supermassive black hole and luminosities of escaping particles such as protons, neutrons, gamma-rays, and neutrinos. We formulate a one-dimensional model of the…
Twenty five years have passed by since models of accretions and jets have separately emerged. Today, it is understood that these two objects are related to each other in a fundamental way. In a binary system, matter from an accretion disk…
In the last decade, high-resolution X-ray spectroscopy has revolutionized our understanding of the role of accretion disk winds in black hole X-ray binaries. Here I present a brief review of the state of wind studies in black hole X-ray…
Multiwavelength variability data, combined with spectral-timing analysis techniques, provides information about the causal relationship between different physical components in accreting black holes. Using fast-timing data and long-term…
Accretion of matter onto black holes is universally associated with strong radiative feedback and powerful outflows. In particular, black hole transients show outflows whose properties are strongly coupled to those of the accretion flow.…