The Position of Sgr A$^*$ at the Galactic Center
Abstract
The absolute position of the compact radio source at the dynamical center of the Galaxy, Sgr A, was known only to an accuracy of in spite of its accurate location with respect to near-IR stellar sources to within 30 milliarcsecond (mas). To remedy this poor positional accuracy, we have selected 15 high-resolution, high-frequency VLA observations of Sgr A carried out in the last 13 years and determined the weighted average position with the average epoch 1992.4 to be at , [1950] = 29\dsec3076, , or , [2000] = 40\dsec0383, which agrees with earlier published values to within the error bars of the earlier measurements. An accurate absolute position of Sgr A can be useful for its identification with sources at other wavelengths, particularly, in soft and hard X-rays with implications for the models of a massive black hole at the Galactic center.
Cite
@article{arxiv.astro-ph/9904142,
title = {The Position of Sgr A$^*$ at the Galactic Center},
author = {F. Yusef-Zadeh and D. Choate and W. Cotton},
journal= {arXiv preprint arXiv:astro-ph/9904142},
year = {2009}
}
Comments
11 pages, one figure and one table. ApJL (in press)