On the Distance to the Bright Nonthermal Radio Sources in the Direction of an Extraordinarily Massive Cluster of Red Giants

Abstract

An extraordinarily massive cluster of red supergiants has been recently reported in the direction of the galactic coordinates $l = 25\rlap.^\circ3$; $b = -0\rlap.^\circ2$. This cluster is associated with an X-ray source, a very high-energy $γ$-ray source, and three bright non-thermal radio sources. The \sl a priori \rm probability of these associations being only line-of-sight coincidences is very small. However, we have analyzed VLA archive data taken toward these three radio sources and find from their HI absorption spectra that they are extragalactic and thus not directly associated with the galactic cluster.