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We explore possible physical origin of correlation between radio wave and very-high-energy neutrino emission in active galactic nuclei (AGN), suggested by recently reported evidence for correlation between neutrino arrival directions and…

High Energy Astrophysical Phenomena · Physics 2021-02-03 Andrii Neronov , Dmitry Semikoz

It has been suggested that optically thin and geometrically thick accretion flows are responsible for the observed radio/X-ray luminosity relation of the X-ray bright galactic nuclei. If this is the case then central supermassive black hole…

Astrophysics · Physics 2007-05-23 Heon-Young Chang , Chul-Sung Choi , Insu Yi

We compute X-ray emission lines from thermal plasma in hot accretion flows. We show that line profiles are strong probes of the gas dynamics, and we present line-ratio diagnostics which are sensitive to the distribution of mass with…

Astrophysics · Physics 2009-10-31 Rosalba Perna , John Raymond , Ramesh Narayan

To explain the broad-band spectral energy distributions (SED) of Seyfert nuclei and QSOs, we study the emission spectrum emerging from a vertical disk-corona structure composed of a two-temperature plasma by solving hydrostatic equilibrium…

Astrophysics · Physics 2009-10-31 T. Kawaguchi , T. Shimura , S. Mineshige

The millimeter bump, as found in high-resolution multi-waveband observations of M87, most possibly comes from the synchrotron emission of thermal electrons in advection dominated accretion flow(ADAF). It is possible to constrain the…

High Energy Astrophysical Phenomena · Physics 2017-07-26 Jianchao Feng , Qingwen Wu

Electron-positron pair production by collision of photons is investigated in view of application to pulsar physics. We compute the absorption rate of individual gamma-ray photons by an arbitrary anisotropic distribution of softer photons,…

High Energy Astrophysical Phenomena · Physics 2018-01-24 Guillaume Voisin , Fabrice Mottez , Silvano Bonazzola

Magnetic reconnection in current layers that form intermittently in radiatively inefficient accretion flows onto black holes is a promising mechanism for particle acceleration and high-energy emission. It has been recently proposed that…

High Energy Astrophysical Phenomena · Physics 2025-12-23 Hayk Hakobyan , Amir Levinson , Lorenzo Sironi , Alexander Philippov , Bart Ripperda

We consider the behavior of matter in the accretion column that emerges under accretion in binary systems near the surface of a white dwarf. The plasma heated in a standing shock wave near the white dwarf surface efficiently radiates in the…

High Energy Astrophysical Phenomena · Physics 2013-12-18 Andrey Semena , Mikhail Revnivtsev

X-ray continuum spectra of super-Eddington accretion flow are studied by means of Monte Carlo radiative transfer simulations based on the radiation hydrodynamic simulation data, in which both of thermal and bulk Compton scatterings are…

High Energy Astrophysical Phenomena · Physics 2017-12-20 Takaaki Kitaki , Shin Mineshige , Ken Ohsuga , Tomohisa Kawashima

Rather than accreting via a disk, some White Dwarfs (WDs) in quiescent Dwarf Novae (DN) could accrete via an Advection-Dominated Accretion Flow (ADAF) possibly responsible for the X-ray Bremsstrahlung emission observed. Such a hot accretion…

Astrophysics · Physics 2009-10-31 Kristen Menou , Rosalba Perna , John Raymond

We derived simple analytical parametrizations for energy distributions of photons, electrons, and neutrinos produced in interactions of relativistic protons with an isotropic monochromatic radiation field. The results on photomeson…

Astrophysics · Physics 2009-01-16 S. R. Kelner , F. A. Aharonian

Sagittarius A* is a compact radio source at the Galactic center, powered by accretion of fully ionized plasmas into a supermassive black hole. However, the radio emission cannot be produced through the thermal synchrotron process by a…

High Energy Astrophysical Phenomena · Physics 2009-04-02 Kyle W. Martin , Siming Liu , Chris Fragile , Cong Yu , Chris L. Fryer

Accreting sources such as AGN, X-ray binaries or gamma-ray bursts are known to be strong, high energy emitters. The hard emission is though to originate from plasmas of thermal and/or non-thermal high energy particles. Not only does this…

Astrophysics · Physics 2008-11-03 R. Belmont , J. Malzac , A. Marcowith

The avalanche mechanism of plasma production in active galactic nuclei (AGNs) is detailed, and constraints on system parameters needed for efficient electron-positron pair cascades are explored. Whether an AGN falls within this favorable…

High Energy Astrophysical Phenomena · Physics 2026-02-03 Mikhail V. Medvedev , Andrzej A. Zdziarski

In this Letter we investigate the properties of advection-dominated accretion flows (ADAFs) fed by the evaporation of a Shakura-Sunyaev accretion disk (SSD). In our picture the ADAF fills the central cavity evacuated by the SSD and extends…

Astrophysics · Physics 2009-10-31 R. Turolla , C. P. Dullemond

We consider electron acceleration by obliquely propagating fast mode waves in magnetically dominated accretion disk coronae. For low coronal plasma densities, acceleration can exceed Coulomb drag at lower energies and energize electrons out…

Astrophysics · Physics 2016-08-30 Hui Li , James A. Miller

The energy spectrum for high energy $\gamma$-rays ($E_\gamma \geq 10$ MeV) from the process $pp \to \gamma \gamma X$ emitted at $90^0$ in the laboratory frame has been measured at an energy below the pion production threshold, namely, at…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. S. Khrykin

Clusters of galaxies are believed to be capable to accelerate protons at accretion shocks to energies exceeding 10^18 eV. At these energies, the losses caused by interactions of cosmic rays with photons of the Cosmic Microwave Background…

High Energy Astrophysical Phenomena · Physics 2016-08-17 G. Vannoni , F. A. Aharonian , S. Gabici , S. R. Kelner , A. Prosekin

In this work, we investigate synchrotron emission and the observational signatures of anisotropic non-thermal electrons during magnetic-flux eruptions in a magnetically arrested disk, using 3D GRMHD simulations. Non-thermal electrons are…

High Energy Astrophysical Phenomena · Physics 2026-05-18 Fan Zhou , Jiewei Huang , Yuehang Li , Zhenyu Zhang , Yehui Hou , Minyong Guo , Bin Chen

We present global radiation GRMHD simulations of strongly magnetized accretion onto a spinning, stellar mass black hole at sub-Eddington rates. Using a frequency-dependent Monte Carlo procedure for Compton scattering, we self-consistently…

High Energy Astrophysical Phenomena · Physics 2021-10-04 Jason Dexter , Nicolas Scepi , Mitchell C. Begelman