1303.3893 (A. Sadowski et al.)

Location of the bow shock ahead of cloud G2 at the Galactic Center    [PDF]

A. Sadowski, R. Narayan, L. Sironi, F. Ozel

We perform detailed magnetohydrodynamic simulations of interaction between the gas cloud G2 with the accretion flow around the Galactic Center black hole Sgr A$^*$. We take as our initial conditions a steady-state, converged solution of the accretion flow we obtained using the general-relativistic magnetohydrodynamic code HARM. Using the observed parameters for the cloud's orbit, we compute the interaction of the cloud with the ambient gas and identify the shock structure that forms ahead of the cloud. We show that for many configurations, the cloud front crossed the orbit pericenter around January 2013 and that the first signatures of the shock, i.e., synchrotron radio emission from electrons accelerated at the bow shock, should already be visible. We argue that the radio emission is likely to reach peak values in February/March 2013.

View original: http://arxiv.org/abs/1303.3893