A study of unknown X-ray sources

Abstract

We analyze the X-ray spectra and light curves of five unknown X-ray sources found in the observations obtained by the XMM-Newton satellite. For two objects we have found X-ray flares. Three other objects have X-ray spectra similar to those of enigmatic 𝛾 Cas analogs and may be new candidates for such stars. All the considered sources are faintly visible in the DSS optical images. We suggest that all the studied objects can be either very distant stars or transient sources. Multifaceted