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arXiv · 1509.06251

Detecting Stars at the Galactic Centre via Synchrotron Emission

Idan Ginsburg·Xiawei Wang·Abraham Loeb·Ofer Cohen
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Abstract

Stars orbiting within 1$\arcsec$ of the supermassive black hole in the Galactic Centre, Sgr A*, are notoriously difficult to detect due to obscuration by gas and dust. We show that some stars orbiting this region may be detectable via synchrotron emission. In such instances, a bow shock forms around the star and accelerates the electrons. We calculate that around the 10 GHz band (radio) and at 10$^{14}$ Hz (infrared) the luminosity of a star orbiting the black hole is comparable to the luminosity of Sgr A*. The strength of the synchrotron emission depends on a number of factors including the star's orbital velocity. Thus, the ideal time to observe the synchrotron flux is when the star is at pericenter. The star S2 will be $\sim 0.015\arcsec$ from Sgr A* in 2018, and is an excellent target to test our predictions.

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Idan Ginsburg, Xiawei Wang, Abraham Loeb, Ofer Cohen. 2015-09-21. Detecting Stars at the Galactic Centre via Synchrotron Emission. https://doi.org/10.1093/mnrasl/slv138

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