POLARIZED EMISSION OF SAGITTARIUS A

We explore the parameter space of the two-temperature pseudo-Newtonian Keplerian accretion flow model for the millimeter and shorter wavelength emission from Sagittarius A*. A general relativistic (GR) ray-tracing code is used to treat the radiative transfer of polarized synchrotron emission from the flow. The synchrotron self-Comptonization and bremsstrahlung emission components are also included. It is shown that the model can readily account for the millimeter to submillimeter emission characteristics with an accretion rate of similar to 6 x 10(17) g s(-1) and an inclination angle of similar to 40 degrees. However, the corresponding model-predicted near-infrared (NIR) and X-ray fluxes are more than one order of magnitude lower than the observed quiescent state values. While the extended quiescent-state X-ray emission has been attributed to thermal emission from the large-scale accretion flow, the NIR emission and flares are likely dominated by emission regions either within the last stable orbit of a Schwarzschild black hole or associated with outflows. With the viscous parameter derived from numerical simulations, there is still a degeneracy between the electron heating rate and the magnetic parameter. A fully GR treatment with the black hole spin incorporated will resolve these issues.