Testing the Radiatively Inefficient Accretion Flow Model for Sagittarius A* Using the Size Measurements

Graduate School, Chinese Academy of Sciences, Peping, Beijing, China
The Astrophysical Journal (Impact Factor: 5.99). 12/2008; 642(1):L45. DOI: 10.1086/504475
Source: arXiv


Recent radio observations by the Very Long Baseline Array 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. We find that after taking into account the scattering of the interstellar electrons, the predicted sizes are consistent with the observations. We further predict an image of Sgr A* at 1.3 mm that can be tested by future observations.

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    • "All such theoretical interpretations have observational support as it was recently reported that both X-ray flares and the outflows are originated from the vicinity of the black hole (Junor et al. 1999;Biretta et al. 2002;Falcke 1999). The typical size of the post-shock flow which possibly responsible for various diverse phenomenon is reasonably coherent with the observational results (Yuan et al. 2006). In this work, we use pseudo-Kerr potential introduced by (Mondal and Chakrabarti 2006) that successfully describe the similar space time geometry around a Kerr black hole as far as the transonic properties of the flow is concerned. "
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