Related papers: Observing the Accretion Stream in Polars
An extended magnetosphere of a strongly magnetized accreting white dwarf (known as a polar) prevents the formation of an accretion disk and the matter is channelled to the magnetic pole(s). A few such sources show quasi-periodic…
We present a simple heuristic model for the time-averaged soft X-ray temperature distribution in the accretion spot on the white dwarf in polars. The model is based on the analysis of the Chandra LETG spectrum of the prototype polar AM Her…
Recent works recognized lidars as an inherently streaming data source and showed that the end-to-end latency of lidar perception models can be reduced significantly by operating on wedge-shaped point cloud sectors rather then the full point…
One of the fundamental properties of an intermediate polar is the dynamical nature of the accretion flow as it encounters the white dwarf's magnetosphere. Many works have presumed a dichotomy between disk-fed accretion, in which the WD…
The spectroscopic features of white dwarfs are formed in the thin upper layer of their stellar photosphere. These features carry information about the white dwarf's surface temperature, surface gravity, and chemical composition (hereafter…
Spectral properties of super-Eddington accretion flows are investigated by means of a parallel line-of-sight calculation. The subjacent model, taken from two-dimensional radiation hydrodynamic simulations by Ohsuga et al. (2005), consists…
We have developed a model of the high-energy accretion region for magnetic cataclysmic variables and applied it to {\it Extreme Ultraviolet Explorer} observations of 10 AM Herculis type systems. The major features of the EUV light curves…
We present a pilot study of atmospheres of accreting magnetic white dwarfs irradiated by intense fluxes at ultraviolet to infrared wavelengths. The model uses a standard LTE stellar atmosphere code which is expanded by introducing an…
{Abridged} We investigate the observability of cold accretion streams at redshift 3 via Lyman-alpha (Lya) emission and the feasibility of cold accretion as the main driver of Lya blobs (LABs). We run cosmological zoom simulations focusing…
An accretion flow onto a supermassive black hole is the primary process powering quasars. However, a geometry of this flow is not well constrained. Both global MHD simulations and observations suggest that there are several emission…
We present optical photometry of six intermediate polars that exhibit transitions to a low-flux state. For four of these systems, DW Cnc, V515 And, V1223 Sgr and RX J2133.7+5107, we are able to perform timing analysis in and out of the low…
The origin of the hard, bright X-ray emission that defines the gamma Cas analog class of Be stars remains an outstanding question in Be star literature. This work explores the possibility that the X-ray flux is produced by accretion onto a…
We present the Transiting Exoplanet Surveying Satellite (TESS) light curve of the intermediate polar YY Draconis (YY Dra, also known as DO Dra). The power spectrum indicates that while there is stream-fed accretion for most of the…
A significant fraction of white dwarfs show metal lines indicative of pollution with planetary material but the accretion process remains poorly understood. The main aim of this paper is to produce a road-map illustrating several potential…
We follow the time dependent thermal evolution of a white dwarf (WD) undergoing sudden accretion in a dwarf nova outburst, using both simulations and analytic estimates. The post-outburst lightcurve clearly separates into early times when…
In a previous paper, we presented the global solution of a new accretion flow model, namely luminous hot accretion flows (LHAFs). In this {\em Letter}, we first show the corresponding thermal equilibrium curve of LHAFs in the mass accretion…
We present a new mapping algorithm, the Accretion Stream Mapping, which uses the complete emission-line light curve to derive spatially resolved intensity distributions along the stream on a surface created as a duodecadon shaped tube. We…
We present the results of a set of high-resolution simulations of the merging process of two white dwarfs. In order to do so, we use an up-to-date Smoothed Particle Hydrodynamics code which incorporates very detailed input physics and an…
We examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the…
A proposed setting for thermonuclear (Type Ia) supernovae is a white dwarf that has gained mass from a companion to the point of carbon ignition in the core. In the early stages of carbon burning, called the simmering phase, energy released…