Evidence for a Highly Compact X-Ray Source

Abstract

A detailed spectrum of the X-ray source GX 340+0 is presented. The spectrum may be fitted from 1 to 10 keV by a blackbody model at T = 1.5 X 10 K, subject to heavy photoelectric absorption. Unlike X-ray sources previously reported, the spectrum is not also compatible with power-law or thermalbremsstrahlung models. If the source is a blackbody at the distance indicated by its X-ray absorption, its radius is 8 km and luminosity 3 X 10 ergs 1 This source may provide direct evidence for the existence of a neutron star.