Thermal and Non-thermal Signatures from Accretion Disk and Stellar Wind Interactions: the Case of Sgr A*

The Galactic center (GC) is a dense environment which is known to harbor massive, main-sequence stars and is believed to hold a large population of radio pulsars. Interactions between the stellar winds of these objects with the accretion flow surrounding Sgr A* provide an excellent probe into its properties. These interactions lead to the formation of a bow shock structure in the stellar winds, the geometry of which is well described through a semi-analytical model. The application of this model to the pericenter passage of S2, the brightest member of the S-Cluster, shows that the shocked stellar wind may produce a month-long X-ray flare via thermal bremsstrahlung emission, with a peak luminosity above the quiescent X-ray emission of Sgr A*. We also show that the application of this model to one fiducial radio pulsar residing in the inner 0.1 pc of the GC may give rise to a steady radio emission in the few GHz range with a luminosity comparable to current observations.

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