A testable stochastic acceleration model for flares in sagittarius A*

Siming Liu, Vahé Petrosian, Fulvio Melia, Christopher L. Fryer

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

The near-IR and X-ray flares in Sagittarius A* are believed to be produced by relativistic electrons via synchrotron and synchrotron self-Comptonization, respectively. These electrons are likely energized by turbulent plasma waves through second-order Fermi acceleration that, in combination with the radiative cooling processes, produces a relativistic Maxwellian distribution in the steady state. This model has four principal parameters, namely the magnetic field B, the electron density n and temperature γcmec2, and the size of the flare region R. In the context of stochastic acceleration, the quantities Rn1/2B and γcRn should remain nearly constant in time. Therefore, simultaneous spectroscopic observations in the NIR and X-ray bands can readily test the model, which, if proven to be valid, may be used to determine the evolution of the plasma properties during an eruptive event with spectroscopic observations in either band or simultaneous flux density measurements in both bands. The formulae can be applied to other isolated or confined systems, where electrons are accelerated to relativistic energies by plasma wave turbulence and produce most of the emission via synchrotron processes.

Original languageEnglish (US)
Pages (from-to)1020-1025
Number of pages6
JournalAstrophysical Journal
Volume648
Issue number2 I
DOIs
StatePublished - Sep 10 2006

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flares
synchrotrons
plasma waves
plasma
electron
Maxwell-Boltzmann density function
electrons
electron density
x rays
flux density
turbulence
magnetic field
cooling
magnetic fields
energy
temperature
parameter
distribution
test

Keywords

  • Acceleration of particles
  • Black hole physics
  • Galaxy: center
  • Plasmas
  • Radiation mechanisms: thermal
  • Turbulence

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

A testable stochastic acceleration model for flares in sagittarius A*. / Liu, Siming; Petrosian, Vahé; Melia, Fulvio; Fryer, Christopher L.

In: Astrophysical Journal, Vol. 648, No. 2 I, 10.09.2006, p. 1020-1025.

Research output: Contribution to journalArticle

Liu, Siming ; Petrosian, Vahé ; Melia, Fulvio ; Fryer, Christopher L. / A testable stochastic acceleration model for flares in sagittarius A*. In: Astrophysical Journal. 2006 ; Vol. 648, No. 2 I. pp. 1020-1025.
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