相关论文: X-winds in Action

In this paper we propose and examine a physical mechanism which can lead to the generation of noise in the mass accretion rate of low mass X-ray binaries on time-scales comparable to the orbital period of the system. We consider modulations…

Powerful outflows along the accretion disk, known as disk winds, are sometimes launched in black hole X-ray binaries. These winds often manifest themselves in X-ray spectra as blueshifted, highly ionized absorption lines. Previous…

Weakly magnetized neutron stars (WMNS) are complicated sources with challenging phenomenology. For decades, they have been studied via spectrometry and timing. It has been established that the spectrum of WMNSs consists of several…

We address two outstanding issues in the sequential accretion scenario for gas giant planet formation, the retention of dust grains in the presence of gas drag and that of cores despite type I migration. The efficiency of these processes is…

Variation of mass supply rate from the companion can be smeared out by viscous processes inside an accretion disk. By the time the flow reaches the inner edge, the variation in X-rays needs not reflect the true variation of the rate at the…

We find the Green's functions for the accretion disk with the fixed outer radius and time-independent viscosity. With the Green's functions, a viscous evolution of the disk with any initial conditions can be described. Two types of the…

Enhanced angular momentum transfer through the boundary layer near the surface of weakly magnetised accreting star is required in order to explain the observed accretion timescales in low-mass X-ray binaries, cataclysmic variables or young…

Rings and gaps are being observed in an increasing number of disks around young stellar objects. We illustrate the formation of such radial structures through idealized, 2D (axisymmetric) resistive MHD simulations of coupled disk-wind…

A review of wind accretion in HMXB is presented. We focus on different regimes of quasi-spherical accretion onto a NS: supersonic (Bondi) accretion, which takes place when the captured matter cools down rapidly and falls supersonically…

Wind-fed high-mass X-ray binaries are powered by accretion of the radiatively driven wind on the compact star. Accretion-generated X-rays alter the ionization state of the wind. Because higher ionization states drive the wind less…

We use Smoothed Particle Hydrodynamics to study viscous accretion flows around a weakly magnetic neutron star. We show the formation of multiple ``boundary" layers in presence of both cooling and viscosity. We find that with the…

Identifying generic physical mechanisms responsible for the generation of magnetic fields and turbulence in differentially rotating flows is fundamental to understand the dynamics of astrophysical objects such as accretion disks and stars.…

We present an analysis of ionized X-ray disk winds observed in the Fe K band of four stellar-mass black holes observed with Chandra, including 4U 1630-47, GRO J1655-40, H 1743-322, and GRS 1915+105. High-resolution photoionization grids…

We reconsider the structure of thermally driven rotating Parker wind. Rotation, without \Bf, changes qualitatively the structure of the subsonic region: solutions become non-monotonic and do not extend to the origin. For small angular…

We carry out the first robust numerical simulation of accretion flows on a weakly magnetized neutron star using Smoothed Particle Hydrodynamics (SPH). We follow the Two-Component Advective Flow (TCAF) paradigm for black holes, and focus…

Accretion discs in strong gravity ubiquitously produce winds, seen as blueshifted absorption lines in the X-ray band of both stellar mass X-ray binaries (black holes and neutron stars), and supermassive black holes. Some of the most…

The distribution of neutron stars (NS's) is determined by stationary solution of the Fokker-Planck equation. In this work using the observed period changes for four systems: Vela X-1, GX 301-2, Her X-1 and Cen X-3 we determined D, the…

The accretion process in a typical S-type symbiotic star, targeting~AG Draconis, is investigated through 3D hydrodynamical simulations using the FLASH code. Regardless of the wind velocity of the giant star, an accretion disk surrounding…

Multiple spectroscopic lines of different elements observed in winds from X-ray binaries (XRBs), based on one zone model, indicate super-solar abundance of elements, e.g. Mg, Si, S, Ar, Ca, Cr, Mn, Co. The one zone model considers similar…

We suggest a possible mechanism of efficient transport of the large-scale external magnetic flux inward through a turbulent accretion disk. The outward drift by turbulent diffusion which limits the effectiveness of this process is reduced…