相关论文: Coronal ejection and heating in variable-luminosit…
The outburst cycles of black hole X-ray transients are now generally understood as caused by a thermal instability in the accretion disk, the same mechanism as in dwarf novae outbursts. During quiescence the accretion occurs via a cool disk…
The heating and cooling of transiently accreting neutron stars provides a powerful probe of the structure and composition of their crust. Observations of superbursts and crust cooling of accretion-heated neutron stars require more heat…
We conduct one-dimensional stellar evolution simulations in the mass range $13-20 M_{\odot}$ to late core collapse times and find that an inner vigorous convective zone with large specific angular momentum fluctuations appears at the edge…
In the X-ray spectra of AGNs, a noticeable excess of soft X-rays is typically detected beyond the extrapolation of the power-law trend observed between 2-10 keV. In the scenario of warm Comptonization, observations propose a warm corona…
The X-ray emission from bright active galactic nuclei (AGNs) is believed to originate in a hot corona lying above a cold, geometrically thin accretion disk. A highly concentrated corona located within $\sim10$ gravitational radii above the…
Most of the X-ray emission from luminous accreting black holes emerges from within 20 gravitational radii. The effective emission radius is several times smaller if the black hole is rapidly spinning. General Relativistic effects can then…
We calculate the degree of linear polarization of radiation from stars having planets that may not be resolved spatially. We assume single scattering by water and silicate particulates in the planetary atmosphere. The dilution of the…
The conversion of neutron matter into strange matter in a neutron star occurs through the non-leptonic weak-interaction process. We study the energy loss of the neutron star by the emission of axions in that process. Owing to that process,…
The increase in spin frequency as the burning atmospheres of TypeI X-ray bursts cool provides a strong constraint on the radius of the underlying neutron star. If the change in spin frequency is due to a change in the thickness of the…
The effect of rotation of a star on the distribution of chemical species in radiative zones is discussed. Gravity darkening generates a large radiative force on heavy element ions which is directed toward the equatorial plane. Taking iron…
The existence of hot, X-ray luminous gaseous coronae surrounding present day L* galaxies is a generic prediction of galaxy formation theory in the cold dark matter cosmogony. While extended X-ray emission has been known to exist around…
It is essential that there be coordinated and co-optimized observations in X-rays, gamma-rays, and EUV during the peak of solar cycle 26 (~2036) to significantly advance our understanding of impulsive energy release in the corona. The open…
We present a theoretical model for the thermal X-ray emission and cooling of isolated pulsars, assuming that pulsars are solid quark stars. We calculate the heat capacity for such a quark star, and the results show that the residual thermal…
The time dependent evolution of the accretion disk around black hole is computed. The classical description of the $\alpha$-viscosity is adopted so the evolution is driven by the instability operating in the innermost radiation-pressure…
Context: According to theory, high-energy emission from the coronae of cool stars can severely erode the atmospheres of orbiting planets. No observational tests of the long term effects of erosion have yet been made. Aims: To analyze the…
Recent observations suggest that in black hole X-ray binaries jet/outflow formation is related to the hot plasma in the vicinity of the black hole, either in the form of an advection-dominated accretion flow at low accretion rates or in a…
A subset of ultraluminous X-ray sources (those with luminosities < 10^40 erg/s) are thought to be powered by the accretion of gas onto black holes with masses of ~5-20 M_solar, probably via an accretion disc. The X-ray and radio emission…
Recent studies have indicated that the emission of gravitational waves at the merger of two black holes gives a kick to the final black hole. If the supermassive black hole at the center of a disk galaxy is kicked but the velocity is not…
Because of the tremendous densities that exist in the cores of neutron stars, a significant fraction of the matter in the cores of such stars is likely to exist in the form of hyperons. Depending on spin frequency, the hyperon content…
We study the effects of thermal conduction in a hot, active corona above an accretion disk. We assume that all of the dissipative heating takes place in the corona. We find that the importance of conduction decreases with increases in the…