A Radio Nebula Surrounding the Ultra-luminous X-ray Source in NGC 5408
Abstract
New radio observations of the counterpart of the ultraluminous X-ray source in NGC 5408 show for the first time that the radio emission is resolved with an angular size of 1.5 to 2.0 arcseconds. This corresponds to a physical size of 35-46 pc, and rules out interpretation of the radio emission as beamed emission from a relativistic jet. In addition, the radio spectral index of the counterpart is well determined from three frequencies and found to be alpha=-0.8 pm 0.2. The radio emission is likely to be optically-thin synchrotron emission from a nebula surrounding the X-ray source. The radio luminosity of the counterpart is 3.8 x 10^34 erg/s and the minimum energy required to power the nebula is ~1 x 10^49 erg. These values are two orders of magnitude larger than in any Galactic nebula powered by an accreting compact object.
Keywords
Cite
@article{arxiv.0705.1978,
title = {A Radio Nebula Surrounding the Ultra-luminous X-ray Source in NGC 5408},
author = {Cornelia C. Lang and Philip Kaaret and Stephane Corbel and Allison Mercer},
journal= {arXiv preprint arXiv:0705.1978},
year = {2019}
}
Comments
6 pages, 6 figures, to appear in ApJ, 1 Sept 2007