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NEAR-INFRARED POLARIMETRY OF FLARES FROM Sgr A* WITH SUBARU/CIAO
- Source :
- The Astrophysical Journal. 702:L56-L60
- Publication Year :
- 2009
- Publisher :
- American Astronomical Society, 2009.
-
Abstract
- We have performed near-infrared monitoring observations of Sgr A*, the Galactic center radio source associated with a supermassive black hole, with the near-infrared camera CIAO and the 36-element adaptive optics system on the Subaru telescope. We observed three flares in the Ks band (2.15micron) during 220 min monitoring on 2008 May 28, and confirmed the flare emission is highly polarized, supporting the synchrotron radiation nature of the near-infrared emission. Clear variations in the degree and position angle of polarization were also detected: an increase of the degree of polarization of about 20 %, and a swing of the position angle of about 60 - 70 degrees in the declining phase of the flares. The correlation between the flux and the degree of polarization can be well explained by the flare emission coming from hotspot(s) orbiting Sgr A*. Comparison with calculations in the literature gives a constraint to the inclination angle i of the orbit of the hotspot around Sgr A*, as 45 < i < 90 degrees (close to edge-on).<br />14 pages, 4 figures, Accepted for publication in ApJ Letters. For higher resolution, see http://www.kusastro.kyoto-u.ac.jp/~shogo/paper/ApJ/SgrAS08/09NishiyamaSgrASNIRPol.pdf
- Subjects :
- Physics
Supermassive black hole
Astrophysics::High Energy Astrophysical Phenomena
Galactic Center
FOS: Physical sciences
Synchrotron radiation
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
Polarization (waves)
Position angle
Astrophysics - Astrophysics of Galaxies
law.invention
Space and Planetary Science
law
Astrophysics of Galaxies (astro-ph.GA)
Astrophysics::Solar and Stellar Astrophysics
Degree of polarization
Subaru Telescope
Astrophysics::Galaxy Astrophysics
Flare
Subjects
Details
- ISSN :
- 15384357 and 0004637X
- Volume :
- 702
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal
- Accession number :
- edsair.doi.dedup.....e08dd0579cf9eb1d616b602d068ad6e3