SYNCHROTRON BLOB MODEL OF INFRARED AND X-RAY FLARES FROM SAGITTARIUS A*

Journal Article · Sat Jan 01 00:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/726/1/54· OSTI ID:21567707

Kusunose, Masaaki ^[1]; Takahara, Fumio ^[2]

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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)

Sagittarius A* in the Galactic center harbors a supermassive black hole and exhibits various active phenomena. Besides quiescent emission in radio and submillimeter radiation, flares in the near-infrared (NIR) and X-ray bands are observed to occur frequently. We study a time-dependent model of the flares, assuming that the emission is from a blob ejected from the central object. Electrons obeying a power law with the exponential cutoff are assumed to be injected in the blob for a limited time interval. The flare data of 2007 April 4 were used to determine the values of model parameters. The spectral energy distribution of flare emission is explained by nonthermal synchrotron radiation in the NIR and X-ray bands. The model light curves suggest that electron acceleration is still underway during the rising phase of the flares. GeV {gamma}-rays are also emitted by synchrotron self-Compton scattering, although their luminosity is not strictly constrained by the current model. If the GeV emission is faint, the plasma blob is dominated by the magnetic energy density over the electron kinetic energy density. Observations in the GeV band will clarify the origin of the blob.

• OSTI ID: 21567707
• Journal Information: Astrophysical Journal, Vol. 726, Issue 1; Other Information: DOI: 10.1088/0004-637X/726/1/54; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCELERATION
BLACK HOLES
COMPTON EFFECT
DENSITY
ELECTRONS
EMISSION
ENERGY DENSITY
ENERGY SPECTRA
GALAXIES
GAMMA RADIATION
INFRARED RADIATION
KINETIC ENERGY
LUMINOSITY
SYNCHROTRON RADIATION
X RADIATION
BASIC INTERACTIONS
BREMSSTRAHLUNG
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY
FERMIONS
INTERACTIONS
IONIZING RADIATIONS
LEPTONS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SCATTERING
SPECTRA