The Size of Sgr A

摘要：

The nonthermal radio source Sgr A at the Galactic center has been known to be extremely compact since its discovery. Following a brief introduction to its size measurements (including its discovery, interstellar scattering effect and its elongated structure), we describe the detection of an intrinsic size of only l AU for Sgr A. When combined with the mass estimate of Sgr A, these size measurements provide strong evidence that Sgr A is a super-massive black hole. Results from the simulation of the black hole shadow image and the corresponding visibility analysis indicate that future sub-millimeter VLBI experiments are critical and promising to probe the Galactic center black hole. High quality multi-epoch radio interferometric images of Sgr A with a wavelength coverage from long centimeter to short millimeter are needed in order to pursue the two- dimensional structure for the scattering angle and the intrinsic source structure, and the corresponding size variation.

关键词： Galactic center Radio Interferometry

作者: Zhi-Qiang Shen

作者单位: Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai 200030, China

会议类型: 国际会议

会议名称: 紧凑型物体的天体物理学国际会议(International Conference on Astrophysics of Compact Objects)

会议地点: 安徽黄山

会议语种:英文

页码: 340-347

在线出版日期: 2007-07-01（万方平台首次上网日期，不代表论文的发表时间）