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相关论文: Modeling Dipolar Post-Shock Accretion Columns for …

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In order to confirm the anisotropic effect of resonance photons in hot accretion columns on white dwarfs in magnetic cataclysmic variables, proposed by Terada etal (2001), systematic studies with ASCA of 7 polars and 12 intermediate polars…

天体物理学 · 物理学 2015-06-24 Yukikatsu Terada , Manabu Ishida , Kazuo Makishima

We describe a geometric model for synchrotron and synchrotron self-Compton (SSC) radiation from blazar jets, involving multiple emission zones with turbulent magnetic fields and fully self-consistent seed photon mixing for SSC. Including…

高能天体物理现象 · 物理学 2020-01-08 A. L. Peirson , R. W. Romani

We investigate the global structure of the advection dominated accretion flow around a Schwarzschild black hole where the accretion disc is threaded by toroidal magnetic fields. We consider synchrotron radiative process as an effective…

高能天体物理现象 · 物理学 2017-11-29 Biplob Sarkar , Santabrata Das , Samir Mandal

We explore conditions and structure of accretion disks in short-period Cata- clysmic Variables (CVs), which have evolved beyond the period minimum. We show that accretion discs in systems with extreme mass ratios grow up to the size of…

太阳与恒星天体物理 · 物理学 2010-10-04 Sergey Zharikov , Gaghik Tovmassian , Andres Aviles , Mauricio Tapia , Miguel Roth

We performed geometric pulsar light curve modeling using static, retarded vacuum, and offset polar cap (PC) dipole $B$-fields (the latter is characterized by a parameter $\epsilon$), in conjunction with standard two-pole caustic (TPC) and…

高能天体物理现象 · 物理学 2017-01-12 Monica Barnard , Christo Venter , Alice K. Harding

We perform 2D axisymmetric radiative relativistic MHD simulations of radiation pressure supported neutron star accretion columns in split-monopole magnetic fields. The accretion columns exhibit quasi-periodic oscillations, which manifest in…

高能天体物理现象 · 物理学 2023-02-01 Lizhong Zhang , Omer Blaes , Yan-Fei Jiang

The disc instability model (DIM) has been very successful in explaining the dwarf nova outbursts observed in cataclysmic variables. When, as in intermediate polars (IP), the accreting white dwarf is magnetized, the disc is truncated at the…

太阳与恒星天体物理 · 物理学 2017-06-28 J. -M. Hameury , J. -P. Lasota

We present a grid of models of accreting brown dwarf systems with circumstellar discs. The calculations involve a self-consistent solution of both vertical hydrostatic and radiative equilibrium along with a sophisticated treatment of dust…

太阳与恒星天体物理 · 物理学 2015-05-19 Nathan Mayne , Tim Harries

Metals in the photospheres of white dwarfs with Teff between 12,000 and 25,000 K should gravitationally settle out of these atmospheres in 1-2 weeks. Temporal variations in the line strengths of these metals could provide a direct…

天体物理学 · 物理学 2011-02-11 Ted von Hippel , Susan E. Thompson

A number of cool white dwarfs with metal traces, of spectral types DAZ, DBZ, and DZ have been found to exhibit infrared excess radiation due to circumstellar dust. The origin of this dust is possibly a tidally disrupted asteroid that formed…

太阳与恒星天体物理 · 物理学 2015-05-13 D. Koester

Hydrogen atmosphere white dwarfs with metal lines, so-called DAZs, require external accretion of material to explain the presence of weak metal line absorption in their photospheres. The source of this material is currently unknown, but…

天体物理学 · 物理学 2009-06-23 J. H. Debes , S. Sigurdsson , B. Hansen

Despite the fact that pulsars have been observed for almost half a century, many questions have remained unanswered. We use the analysis of X-ray observations in order to study the polar cap region of radio pulsars. The size of the hot…

高能天体物理现象 · 物理学 2013-04-19 Andrzej Szary

We have calculated the structures and the emergent spectra of stationary, geometrically thin accretion disks around 100 and 1000 M_sun black holes in both the Schwarzschild and extreme Kerr metrics. Equations of radiative transfer,…

天体物理学 · 物理学 2009-11-10 Y. Hui , J. H. Krolik , I. Hubeny

We present relativistic, radiation magnetohydrodynamic simulations of supercritical neutron star accretion columns in Cartesian geometry, including temperature-dependent, polarization-averaged Rosseland mean opacities accounting for…

高能天体物理现象 · 物理学 2023-07-26 Xin Sheng , Lizhong Zhang , Omer Blaes , Yan-Fei Jiang

The main purpose of this paper is to obtain analytical solutions for radiative transfer equations related to the vertical structure of accretion discs with finite optical depth. In the non-gray atmosphere, we employ the optical-depth…

高能天体物理现象 · 物理学 2020-06-24 Maryam Samadi , Fahimeh Habibi , Shahram Abbassi

We have developed a 3D computer model of polars which includes the accretion stream, the accretion column, the secondary star, and the white dwarf. Each component is represented by a fine grid of surface elements. With brightness values…

天体物理学 · 物理学 2007-05-23 Jens Kube , Boris T. Gaensicke , Klaus Beuermann

It has long been thought that black hole accretion flows are driven by magnetohydrodynamic (MHD) turbulence, and there are now many general relativistic global simulations illustrating the dynamics of this process. However, many challenges…

高能天体物理现象 · 物理学 2026-03-11 Chris Nagele , Julian H. Krolik , Rongrong Liu , Brooks E. Kinch , Jeremy D. Schnittman

We propose a novel theoretical model to describe a physical identity of the soft X-ray excess, ubiquitously detected in many Seyfert galaxies, by considering a steady-state, axisymmetric plasma accretion within the innermost stable circular…

高能天体物理现象 · 物理学 2016-08-17 Keigo Fukumura , Douglas Hendry , Peter Clark , Francesco Tombesi , Masaaki Takahashi

We consider a method for obtaining information on polarization of astronomical objects radiation at diffraction limited resolution - differential speckle polarimetry. As an observable we propose to use averaged cross spectrum of two…

天体物理仪器与方法 · 物理学 2015-06-12 Boris Safonov

We present the black hole accretion code (BHAC), a new multidimensional general-relativistic magnetohydrodynamics module for the MPI-AMRVAC framework. BHAC has been designed to solve the equations of ideal general-relativistic…

广义相对论与量子宇宙学 · 物理学 2017-06-20 Oliver Porth , Hector Olivares , Yosuke Mizuno , Ziri Younsi , Luciano Rezzolla , Monika Moscibrodzka , Heino Falcke , Michael Kramer