Near-infrared Polarimetry of flares from Sgr A* with Subaru-CIAO - Astrophysics > Astrophysics of GalaxiesReportar como inadecuado




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Abstract: We have performed near-infrared monitoring observations of Sgr A*, theGalactic center radio source associated with a supermassive black hole, withthe near-infrared camera CIAO and the 36-element adaptive optics system on theSubaru telescope. We observed three flares in the Ks band 2.15micron during220 min monitoring on 2008 May 28, and confirmed the flare emission is highlypolarized, supporting the synchrotron radiation nature of the near-infraredemission. Clear variations in the degree and position angle of polarizationwere 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 decliningphase of the flares. The correlation between the flux and the degree ofpolarization can be well explained by the flare emission coming from hotspotsorbiting Sgr A*. Comparison with calculations in the literature gives aconstraint to the inclination angle i of the orbit of the hotspot around SgrA*, as 45 < i < 90 degrees close to edge-on.



Autor: Shogo Nishiyama, Motohide Tamura, Hirofumi Hatano, Tetsuya Nagata, Tomoyuki Kudo, Miki Ishii, Rainer Schödel, Andreas Eckart

Fuente: https://arxiv.org/







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