The nature of the X-ray sources in dwarf galaxies in nearby clusters from the KIWICS

• Published in: arXiv.org 2023-07
• Main Authors: \c{S}eyda \c{S}en, Göğüş, Ersin, Peletier, Reynier F, Choque-Challapa, Nelvy, Amiri, Amirnezam
• Format: Article
• Language: English
• Subjects: Dwarf galaxies; Field cameras; Galactic clusters; Luminosity; Neutron stars; Stellar mass; X ray sources; X-ray astronomy; X-rays
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2307.14230

We present a deep search for and analysis of X-ray sources in a sample of dwarf galaxies (M\(_{r}\) < -15.5 mag) located within twelve galaxy clusters from the Kapteyn IAC WEAVE INT Cluster Survey (KIWICS) of photometric observations in the \(\textit{r}\) and \(\textit{g}\) using the Wide Field Camera (WFC) at the 2.5-m Isaac Newton telescope (INT). We first investigated the optical data, identified 2720 dwarf galaxies in all fields and determined their characteristics; namely, their colors, effective radii, and stellar masses. We then searched the \(\textit{Chandra}\) data archive for X-ray counterparts of optically detected dwarf galaxies. We found a total of 20 X-ray emitting dwarf galaxies, with X-ray flux ranging from 1.7\(\times10^{-15}\) to 4.1\(\times10^{-14}\) erg cm\(^{-2}\) s\(^{-1}\) and X-ray luminosities varying from 2\(\times10^{39}\) to 5.4\(\times10^{41}\) erg s\(^{-1}\). Our results indicate that the X-ray luminosity of the sources in our sample is larger than the Eddington luminosity limit for a typical neutron star, even at the lowest observed levels. This leads us to conclude that the sources emitting X-rays in our sample are likely black holes. Additionally, we have employed a scaling relation between black hole and stellar mass to estimate the masses of the black holes in our sample, and have determined a range of black hole masses from 4.6\(\times10^{4}\) to 1.5\(\times10^{6}\) M\(_\odot\). Finally, we find a trend between X-ray to optical flux ratio and X-ray flux. We discuss the implications of our findings and highlight the importance of X-ray observations in studying the properties of dwarf galaxies.