------------------------------------------------------------------------
From: Siming Liu  liusm@lanl.gov 
To: gcnews@aoc.nrao.edu
Subject: submit ms.tex ApJL, submitted

%astro-ph/0603136
\documentclass[12pt,preprint]{aastex}

\begin{document}

\title{Testing the Stochastic Acceleration Model for Flares in
Sagittarius A*}

\author{Siming Liu,\altaffilmark{1} Vah\'e Petrosian,\altaffilmark{2}
Fulvio Melia,\altaffilmark{3, 4} and Christopher L. Fryer\altaffilmark
{1, 5}
}

\altaffiltext{1}{Los Alamos National Laboratory, Los Alamos, NM 87545;
liusm@lanl.edu}
\altaffiltext{2}{Center for Space Science and Astrophysics, Department
of Physics and Applied Physics, Stanford
University, Stanford, CA 94305; vahe@astronomy.stanford.edu}
\altaffiltext{3}{Physics Department and Steward Observatory, The
University of Arizona,
Tucson, AZ 85721; melia@physics.arizona.edu}
\altaffiltext{4}{Sir Thomas Lyle Fellow and Miegunyah Fellow.}
\altaffiltext{5}{Physics Department, The University of Arizona,
Tucson, AZ 85721; fryer@lanl.gov}

\begin{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 (SSC), 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 $n$,
their ``temperature'' $\gamma_c\,m_e c^2$, and the size of the flare
region $R$. In the context of
stochastic acceleration by plasma waves, the quantities $R\,n^{1/2} B$
and $\gamma_c R n$ 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 formulation we
develop here may also be
applicable to other sources radiating via thermal synchrotron and SSC
processes.

\end{abstract}

\end{document}
-- 
Siming Liu
T-6, MS B227
Los Alamos National Laboratory
Los Alamos, NM 87545
Tel: 505-667-3862
Fax: 505-664-0007