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Simultaneous Multi-Wavelength Observations of Sgr A* During 2007 April 1-11
- Source :
- The Astrophysical Journal, The Astrophysical Journal, American Astronomical Society, 2009, 706, pp.348-375. ⟨10.1088/0004-637X/706/1/348⟩, The Astrophysical Journal, 2009, 706, pp.348-375. ⟨10.1088/0004-637X/706/1/348⟩
- Publication Year :
- 2009
- Publisher :
- HAL CCSD, 2009.
-
Abstract
- We report the detection of variable emission from Sgr A* in almost all wavelength bands (i.e. centimeter, millimeter, submillimeter, near-IR and X-rays) during a multi-wavelength observing campaign. Three new moderate flares are detected simultaneously in both near-IR and X-ray bands. The ratio of X-ray to near-IR flux in the flares is consistent with inverse Compton scattering of near-IR photons by submillimeter emitting relativistic particles which follow scaling relations obtained from size measurements of Sgr A*. We also find that the flare statistics in near-IR wavelengths is consistent with the probability of flare emission being inversely proportional to the flux. At millimeter wavelengths, the presence of flare emission at 43 GHz (7mm) using VLBA with milli-arcsecond spatial resolution indicates the first direct evidence that hourly time scale flares are localized within the inner 30$\times$70 Schwarzschild radii of Sgr A*. We also show several cross correlation plots between near-IR, millimeter and submillimeter light curves that collectively demonstrate the presence of time delays between the peaks of emission up to three hours. The evidence for time delays at millimeter and submillimeter wavelengths are consistent with the source of emission being optically thick initially followed by a transition to an optically thin regime. In particular, there is an intriguing correlation between the optically thin near-IR and X-ray flare and optically thick radio flare at 43 GHz that occurred on 2007 April 4. This would be the first evidence of a radio flare emission at 43 GHz delayed with respect to the near-IR and X-ray flare emission.<br />replaced with revised version 57 pages, 28 figures, ApJ (in press)
- Subjects :
- [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]
Photon
Astrophysics::High Energy Astrophysical Phenomena
black hole physics
Flux
FOS: Physical sciences
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
01 natural sciences
law.invention
Relativistic particle
accretion
law
0103 physical sciences
Astrophysics::Solar and Stellar Astrophysics
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
Physics
High Energy Astrophysical Phenomena (astro-ph.HE)
Galaxy: center
010308 nuclear & particles physics
accretion disks
[SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]
Compton scattering
Astronomy and Astrophysics
Light curve
Astrophysics - Astrophysics of Galaxies
Wavelength
13. Climate action
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
Millimeter
Astrophysics::Earth and Planetary Astrophysics
Astrophysics - High Energy Astrophysical Phenomena
Flare
Subjects
Details
- Language :
- English
- ISSN :
- 0004637X and 15384357
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal, The Astrophysical Journal, American Astronomical Society, 2009, 706, pp.348-375. ⟨10.1088/0004-637X/706/1/348⟩, The Astrophysical Journal, 2009, 706, pp.348-375. ⟨10.1088/0004-637X/706/1/348⟩
- Accession number :
- edsair.doi.dedup.....91d32bd215c8e19734e95141b221e492