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Related papers: Self-Similar Hot Accretion Flow onto a Neutron Sta…

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We present analytical and numerical solutions which describe a hot, viscous, two-temperature accretion flow onto a rotating neutron star or any other rotating compact star with a surface. We assume Coulomb coupling between the protons and…

Astrophysics · Physics 2009-11-06 Mikhail Medvedev , Ramesh Narayan

We consider hot, two-temperature, viscous accretion onto a rotating, unmagnetized neutron star. We assume Coulomb coupling betweenthe protons and electrons, and free-free cooling from the electrons. We show that the accretion flow has an…

Astrophysics · Physics 2009-10-31 Mikhail V. Medvedev , Ramesh Narayan

(Abridged) A new type of self-similar hot viscous radiative accretion flow onto a rapidly spinning neutron star has recently been discovered. This ``hot brake'' flow forms in the two-temperature zone (close to a central object), but at a…

Astrophysics · Physics 2007-05-23 Mikhail V. Medvedev

We consider hot accretion onto a rapidly spinning neutron star (or any other compact object with a surface). A radiative hot settling flow has been discovered at low accretion rates in the early work by Medvedev & Narayan (2001) and…

Astrophysics · Physics 2009-11-10 Mikhail V. Medvedev

Medvedev & Narayan have described a hot accretion flow onto a spinning neutron star in which the gas viscously brakes the spin of the star. Their self-similar solution has the surprising property that the density, temperature and angular…

Astrophysics · Physics 2009-11-07 Ramesh Narayan , Mikhail V. Medvedev

Numerical simulations of radiative two-temperature hot accretion flows (HAFs) around Neutron stars (NSs) are performed. We assume that all of the energy carried by the HAF around a NS will be thermalized and radiated out at the surface of…

High Energy Astrophysical Phenomena · Physics 2020-02-26 De-Fu Bu , Erlin Qiao , Xiao-Hong Yang

We investigate two-temperature accretion flows onto strongly magnetized compact stars. Matter is accreted in the form of an accretion disc upto the disc radius ($r_{\rm d}$), where, the magnetic pressure exceeds both the gas and ram…

High Energy Astrophysical Phenomena · Physics 2023-04-19 Shilpa Sarkar , Kuldeep Singh , Indranil Chattopadhyay , Philippe Laurent

We perform as the first time hydrodynamic simulations to study the properties of hot accretion flow (HAF) around a neutron star (NS). The energy carried by the HAF will eventually be radiated out at the surface of the NS. The emitted…

High Energy Astrophysical Phenomena · Physics 2019-05-01 De-Fu Bu , Er-Lin Qiao , Xiao-Hong Yang

We describe hot, optically-thin solutions for one-temperature accretion disks around black holes. We include cooling by synchrotron, bremsstrahlung, and Comptonization. Our solutions are thermally and viscously stable, with gas temperatures…

Astrophysics · Physics 2016-08-30 A. A. Esin , R. Narayan , E. Ostriker , I. Yi

We describe new optically thin solutions for rotating accretion flows around black holes and neutron stars. These solutions are advection dominated, so that most of the viscously dissipated energy is advected radially with the flow. We…

Astrophysics · Physics 2009-10-22 Ramesh Narayan , Insu Yi

We present here the solutions of magnetized accretion flows on to a compact object with hard surface such as neutron stars. The magnetic field of the central star is assumed dipolar and the magnetic axis is assumed to be aligned with the…

High Energy Astrophysical Phenomena · Physics 2018-03-14 Kuldeep Singh , Indranil Chattopadhyay

The fundamental difference between accretion around black holes and neutron stars is the inner boundary condition, which affects the behavior of matter very close to the compact objects. This leads to formation of additional shocks and…

High Energy Astrophysical Phenomena · Physics 2021-01-06 Ayan Bhattacharjee , Sandip K. Chakrabarti

Recently, Medvedev & Narayan (2001) discovered a new type of accretion flow, a hot settling flow around a rapidly rotating neutron star. The flow is cooling-dominated and energetically similar to the Shapiro, Lightman, & Eardley (1976, SLE)…

Astrophysics · Physics 2007-05-23 Mikhail V. Medvedev , Ramesh Narayan

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…

High Energy Astrophysical Phenomena · Physics 2019-03-20 Ayan Bhattacharjee , Sandip K. Chakrabarti

Here we study the accretion process around a neutron star, especially for the cases where shock does form in the accretion disk. In case of accretion flows around a black hole, close to the horizon matter is supersonic. On the other hand…

Astrophysics · Physics 2009-11-07 Banibrata Mukhopadhyay

The effectiveness of the thermal coupling of ions and electrons in the context of optically thin, hot accretion flows is investigated. In the limit of complete coupling, we focus on the one-temperature accretion flows. Based on a global…

Astrophysics · Physics 2009-11-13 Feng Yuan , Ronald E. Taam , Yongquan Xue , Wei Cui

Matter falling onto black holes is hot, fully ionized and has to be necessarily transonic. Since the electrons are responsible for radiative cooling via processes like synchrotron, bremsstrahlung and inverse-Compton, therefore the electron…

High Energy Astrophysical Phenomena · Physics 2019-02-20 Shilpa Sarkar , Indranil Chattopadhyay

We study the structure and properties of hot MHD accretion onto a Kerr black hole. In such a system, the hole is magnetically coupled to the inflowing gas and exerts a torque onto the accretion flow. A hot settling flow can form around the…

Astrophysics · Physics 2011-05-10 Mikhail V. Medvedev , Norman Murray

The existence of hot, two-temperature accretion flows is essential to the recent discussions of the low luminosity, hard X-ray emission from accreting neutron stars and black holes in Galactic binaries and massive black holes in low…

Astrophysics · Physics 2009-10-31 Jongmann Yang , Insu Yi

We consider viscous rotating accretion flows in which most of the viscously dissipated energy is stored as entropy rather than being radiated. Such advection-dominated flows may occur when the optical depth is either very small or very…

Astrophysics · Physics 2009-10-22 Ramesh Narayan , Insu Yi
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