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Session: Cosmology and Relativistic Astrophysics

Name: Ms. Cloe Mahe (Universite de la Cote d'Azur)
Coauthors: No coauthors were included.
Type: Poster
Title: A synchrotron cooling model for the NIR/X-ray flares of Sgr A*
Abstract:

Sgr A*, the supermassive black hole at the center of our Galaxy, is accreting mass from its surroundings at an extremely low rate of about 3e-13 M_sun/yr. Sgr A* is therefore a unique laboratory to study the physical processes at work in quiescent accreting systems. The observation of flares with hour-long duration in the near-infrared and X-ray wavelengths from Sgr A* suggests the formation of active flaring regions in the accretion flow of Sgr A* filled with relativistic electrons that produce non-thermal radiation. The aim of this project is to fit the 2014 NIR/X-ray flare from Sgr A* with a synchrotron cooling model using Markov-Chain Monte Carlo simulations. By obtaining the posterior distributions for the parameters describing the flaring region, such as size and magnetic field strength, we are able to study the degeneracies between model parameters and their evolution with time. Our results support a scenario where a hot spot in the accretion of Sgr A* with kG magnetic fields and size of ~1/1000 of the Schwarzschild radius is the production site of the non-thermal flares. Our method can be easily applied to a larger sample of NIR/X-ray flares in order to extract a statistical sample for the properties of the flaring regions.