Statistical and theoretical studies of flares from Sagittarius A*
Abstract
Multi-wavelength flares have routinely been observed from the supermassive black hole, Sagittarius A* (Sgr A*), at our Galactic center. The nature of these flares remains largely unclear, despite many theoretical models. We study the statistical properties of the Sgr A* X-ray flares and find that they are consistent with the theoretical prediction of the self-organized criticality system with the spatial dimension S = 3. We suggest that the X-ray flares represent plasmoid ejections driven by magnetic reconnection (similar to solar flares) in the accretion flow onto the black hole. Motivated by the statistical results, we further develop a time-dependent magnetohydrodynamic (MHD) model for the multi-band flares from Sgr A* by analogy with models of solar flares/coronal mass ejections (CMEs). We calculate the X-ray, infrared flare light curves, and the spectra, and find that our model can explain the main features of the flares.
- Publication:
-
The Multi-Messenger Astrophysics of the Galactic Centre
- Pub Date:
- January 2017
- DOI:
- 10.1017/S1743921316012540
- Bibcode:
- 2017IAUS..322...31L
- Keywords:
-
- Galaxy: center;
- black hole physics;
- accretion;
- accretion disks;
- methods: statistical;
- MHD