Related papers: On photons and matter inversion spheres from compl…
An accretion flow around a black hole has a saddle type sonic point just outside the event horizon to guarantee that the flow enters the black hole supersonically. This feature exclusively present in strong gravity limit makes its marks in…
Recent observations of protostellar cores suggest that most of the material in the protostellar phase is accreted along streamers. Streamers in this context are defined as velocity coherent funnels of denser material potentially connecting…
The phenomenology of accretion disc, coronnae and jets in X-ray binaries is rather well established. However the structure of the accretion flow in the various spectral states is still debated and the connection between the hot flow and…
Young close binaries open central gaps in the surrounding circumbinary accretion disc, but the stellar components may still gain mass from gas crossing through the gap. It is not well understood how this process operates and how the stellar…
Geometrically thick accretion flows may be present in black hole X-ray binaries observed in the low/hard state and in low-luminosity active galactic nuclei. Unlike in geometrically thin disks, the angular momentum axis in these sources is…
We describe the most general nature of accretion and wind flows around a compact object and emphasize on the properties which are special to black hole accretion. The angular momentum distribution in the most general solution is far from…
Topology establishes a unifying framework for a diverse range of scientific areas including particle physics, cosmology, and condensed matter physics. One of the most fascinating manifestations of topology in the context of condensed matter…
High resolution radio imaging of AGN have revealed that some sources present motion of superluminal knots and transverse stratification of their jet. Recent observational projects have provided new observational constraints on the central…
Most powerful jets are observed to emanate from accreting black hole systems. Recent quasi-stationary radiative MHD calculations reveal that jet-launching start in the innermost region of a transition layer (:TL), which is located between…
A model is presented in which the strongest radio-emitting jet outflows are produced in black hole systems when the accretion is a geometrically thick ($H/R \sim 1$) inflow ({\it e.g.}, ADAF, CDAF) {\em and} if the black hole is rotating.…
We calculated the expected microlens light curves for several accretion-flow models and compared the results to find what aspects of distinct flow structures can be extracted from the microlens light curves. As for the flow models, we…
We review the current understanding of accretion flows around compact objects with a special emphasis on advective disks. We discuss the influence of the centrifugal pressure supported high density region around compact objects (where…
Recent observations suggest that mass ejection and mass accretion both decline significantly with time during early protostellar evolution (Bontemps et al. 1996). In the present paper, we propose that this rapid decay of accretion/ejection…
We use local stratified shearing-box simulations to elucidate the impact of two-temperature thermodynamics on the thermal structure of coronae in radiatively efficient accretion flows. Rather than treating the coronal plasma as an…
Using three-dimensional general relativistic magnetohydrodynamic simulations with electron and proton thermodynamics and an electron cooling function, we probe the inner radial and vertical structure of weakly magnetized geometrically thin…
Orbiting matter misaligned with a spinning black hole undergoes Lense-Thirring precession, due to the frame-dragging effect. This phenomenon is particularly relevant for type-C QPOs observed in the hard states of low-mass X-ray binaries.…
Recent observations from Parker Solar Probe have revealed that the solar wind has a highly variable structure. How this complex behaviour is formed in the solar corona is not yet known, since it requires omnipresent fluctuations, which…
Large scale magnetic field threading an accretion disk is a key ingredient in the jet formation model. The most attractive scenario for the origin of such a large scale field is the advection of the field by the gas in the accretion disk…
Light orbiting an accreting black hole may impact the disk or jet multiple times before escaping to the observer, at a variety of angles with respect to the local magnetic field. In this letter, we characterize the imprints of these long…
Solar flare electron acceleration is an efficient process, but its properties (mechanism, location) are not well constrained. Via hard X-ray (HXR) emission, we routinely observe energetic electrons at the Sun, and sometimes we detect…