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Title: A LEPTONIC MODEL OF STEADY HIGH-ENERGY GAMMA-RAY EMISSION FROM Sgr A*

Abstract

Recent observations of Sgr A* by Fermi and HESS have detected steady {gamma}-ray emission in the GeV and TeV bands. We present a new model to explain the GeV {gamma}-ray emission by inverse Compton scattering by nonthermal electrons supplied by the NIR/X-ray flares of Sgr A*. The escaping electrons from the flare regions accumulate in a region with a size of {approx}10{sup 18} cm and magnetic fields of {approx}< 10{sup -4} G. Those electrons produce {gamma}-rays by inverse Compton scattering off soft photons emitted by stars and dust around the central black hole. By fitting the GeV spectrum, we find constraints on the magnetic field and the energy density of optical-UV radiation in the central 1 pc region around the supermassive black hole. While the GeV spectrum is well fitted by our model, the TeV {gamma}-rays, whose spectral index is different from that of the GeV emission, may be from different sources such as pulsar wind nebulae.

Authors:
 [1];  [2]
  1. Department of Physics, School of Science and Technology, Kwansei Gakuin University, Sanda 669-1337 (Japan)
  2. Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka 560-0043 (Japan)
Publication Date:
OSTI Identifier:
22016174
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 748; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; COMPTON EFFECT; COSMIC ELECTRONS; DUSTS; ENERGY DENSITY; GALAXIES; GAMMA RADIATION; MAGNETIC FIELDS; NEBULAE; PHOTON EMISSION; PLASMA; PULSARS; SPECTRA; STARS; TEV RANGE; ULTRAVIOLET RADIATION

Citation Formats

Kusunose, Masaaki, and Takahara, Fumio, E-mail: kusunose@kwansei.ac.jp, E-mail: takahara@vega.ess.sci.osaka-u.ac.jp. A LEPTONIC MODEL OF STEADY HIGH-ENERGY GAMMA-RAY EMISSION FROM Sgr A*. United States: N. p., 2012. Web. doi:10.1088/0004-637X/748/1/34.
Kusunose, Masaaki, & Takahara, Fumio, E-mail: kusunose@kwansei.ac.jp, E-mail: takahara@vega.ess.sci.osaka-u.ac.jp. A LEPTONIC MODEL OF STEADY HIGH-ENERGY GAMMA-RAY EMISSION FROM Sgr A*. United States. doi:10.1088/0004-637X/748/1/34.
Kusunose, Masaaki, and Takahara, Fumio, E-mail: kusunose@kwansei.ac.jp, E-mail: takahara@vega.ess.sci.osaka-u.ac.jp. 2012. "A LEPTONIC MODEL OF STEADY HIGH-ENERGY GAMMA-RAY EMISSION FROM Sgr A*". United States. doi:10.1088/0004-637X/748/1/34.
@article{osti_22016174,
title = {A LEPTONIC MODEL OF STEADY HIGH-ENERGY GAMMA-RAY EMISSION FROM Sgr A*},
author = {Kusunose, Masaaki and Takahara, Fumio, E-mail: kusunose@kwansei.ac.jp, E-mail: takahara@vega.ess.sci.osaka-u.ac.jp},
abstractNote = {Recent observations of Sgr A* by Fermi and HESS have detected steady {gamma}-ray emission in the GeV and TeV bands. We present a new model to explain the GeV {gamma}-ray emission by inverse Compton scattering by nonthermal electrons supplied by the NIR/X-ray flares of Sgr A*. The escaping electrons from the flare regions accumulate in a region with a size of {approx}10{sup 18} cm and magnetic fields of {approx}< 10{sup -4} G. Those electrons produce {gamma}-rays by inverse Compton scattering off soft photons emitted by stars and dust around the central black hole. By fitting the GeV spectrum, we find constraints on the magnetic field and the energy density of optical-UV radiation in the central 1 pc region around the supermassive black hole. While the GeV spectrum is well fitted by our model, the TeV {gamma}-rays, whose spectral index is different from that of the GeV emission, may be from different sources such as pulsar wind nebulae.},
doi = {10.1088/0004-637X/748/1/34},
journal = {Astrophysical Journal},
number = 1,
volume = 748,
place = {United States},
year = 2012,
month = 3
}
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