Testing RIAF model for Sgr A* using the size measurements

Feng Yuan(1,2), Zhi-Qiang Shen(1,2) and Lei Huang(1,3)

(1) Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, China;fyuan,zshen,muduri@shao.ac.cn
(2) Joint Institute for Galaxy and Cosmology (JOINGC) of SHAO and USTC
(3) Graduate School of Chinese Academy of Sciences, Beijing 100039, China

Paper: ApJL, 2006 in press

Weblink: http://www.shao.ac.cn/fyuan

EPrint Server: astro-ph/0603683


Recent radio observations by the VLBA at 7 and 3.5 mm produced the high-resolution images of the compact radio source located at the center of our Galaxy--Sgr A*, and detected its wavelength-dependent intrinsic sizes at the two wavelengths. This provides us with a good chance of testing previously-proposed theoretical models for Sgr A*. In this Letter, we calculate the size based on the radiatively inefficient accretion flow (RIAF) model proposed by Yuan, Quataert & Narayan (2003). We find that the predicted sizes after taking into account the scattering of the interstellar electrons are consistent with the observations. We further predict an image of Sgr A* at 1.3 mm which can be tested by future observations.

Preprints available from the authors at fyuan@shao.ac.cn , or the raw TeX (no figures) if you click here.

Back to the gcnews home-page.