Related papers: SS433: Observation of the circumbinary disc and ex…
The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with…
Stellar mass black holes (SMBHs), forming by the core collapse of very massive, rapidly rotating stars, are expected to exhibit a high density accretion disk around them developed from the spinning mantle of the collapsing star. A wide…
We have found that the bulge of the large, nearby Sb galaxy NGC 7331 rotates retrograde to its disk. Analysis of spectra in the region of the near-IR Ca II triplet along the major axis shows that, in the radial range between 5'' and ~20'',…
We analyzed two observations of the low-mass black hole X-ray binary MAXI J1348-630 from Nuclear Spectroscopic Telescope Array (NuSTAR) during low hard state and hard intermediate state in the 2019 outburst. The reflection components are…
Accreting black holes produce powerful relativistic plasma jets which emit radiation across all observable wavelengths but the details of the initial acceleration and confinement of the jet are uncertain. We apply an innovative new model…
High-dispersion spectroscopic monitoring of HESS J0632+057 has been carried out over four orbital cycles in order to search for orbital modulation, covering the entire orbital phase. We have measured radial velocity of H$\alpha$ emission…
In some Seyfert Galaxies, the hard X-rays that produce fluorescent emission lines are thought to be generated in a hot corona that is compact and located at only a few gravitational radii above the supermassive black hole. We consider the…
A typical galaxy is thought to contain tens of millions of stellar-mass black holes, the collapsed remnants of once massive stars, and a single nuclear supermassive black hole. Both classes of black holes accrete gas from their…
We performed two-dimensional radiation hydrodynamic simulations of supercritical accretion flows around neutron stars (NSs). In contrast with the accretion flows onto black holes (BHs), we find that the shell-shaped high-density regions…
The system TIC 470710327 is comprised of three main-sequence OB stars, with an inner compact 1.10 d eclipsing binary and a non-eclipsing tertiary on a 52.04 d orbit. With the tertiary mass of 14.5-16 $M_{\odot}$ and both components in the…
The X-ray luminosity of black holes is produced through the accretion of material from their companion stars. Depending on the mass of the donor star, accretion of the material falling onto the black hole through the inner Lagrange point of…
Cygnus X-3 is a strong X-ray source (L_X about 10^38 erg/s) which is thought to consist of a compact object, accreting matter from a helium star. We find analytically that the estimated ranges of mass-loss rate and orbital-period derivative…
We have carried out high-resolution spectroscopic observations of the carbon star V Hya, covering the 4.6 micron band of CO. These data, taken over 7 epochs, show that the circumstellar environment of V Hya consists of a complex…
The proto-planetary Red Rectangle nebula is powered by HD 44179, a spectroscopic binary (P = 318 d), in which a luminous post-AGB component is the primary source of both luminosity and current mass loss. Here, we present the results of a…
We used a model of a relativistic accretion disk around a supermassive black hole (SMBH), based on ray-tracing method in the Kerr metric, to study the variations of the composite Fe K$\alpha$ line emitted from two accretion disks around…
We have imaged the X-ray binary SS433 with unprecedented Fourier-plane coverage at 6cm using simultaneously the VLBA, MERLIN, and the VLA, and also at 20cm with the VLBA. At both wavelengths we have securely detected smooth, low-surface…
An object discovered during an infrared survey of the field near the quasar B2 0149+33 has an emission line at 2.25$\mu$m that we interpret as H$\alpha$ at a redshift of 2.43. The K-band image shows two compact components 10 kpc apart…
In this brief note I draw attention to the structure of the stationary Halpha line as a function of orbital phase, using a data set compiled over some years. These data are compared with a set of nightly observations over some 2 orbits. The…
We present a study based on more than 2500 uvby-measurements collected on HD 172189, a new eclipsing binary system with a Delta Sct-type pulsating component that belongs to the open cluster IC 4756. The great interest of this object lies in…
The particle acceleration mechanism in $S^2 \times\mathbb{R}^1$ topology, namely in the spacetime of the five-dimensional compact black string has been studied. The expression of center-of-mass energy of the colliding neutral particles near…