A new search strategy for microquasar candidates using NVSS/2MASS and XMM-Newton data

TL;DR

This paper introduces a refined search method utilizing NVSS, 2MASS, and XMM-Newton data to identify new microquasar candidates, successfully finding 62 previously unidentified sources with potential for further study.

Contribution

The study presents an improved, restrictive cross-identification strategy using modern radio and X-ray data to efficiently discover new microquasar candidates in our Galaxy.

Findings

86 sources with positional coincidence found

24 known objects identified

At least 3 candidates show high-mass X-ray binary characteristics

Abstract

Microquasars are ideal natural laboratories for understanding accretion/ejection processes, studying the physics of relativistic jets, and testing gravitational phenomena. Nevertheless, these objects are difficult to find in our Galaxy. The main goal of this work is to increase the number of known systems of this kind. We have developed an improved search strategy based on positional cross-identification with very restrictive selection criteria to find new MQs, taking advantage of more sensitive modern radio and X-ray data. We find 86 sources with positional coincidence in the NVSS/XMM catalogs at |b|<10 deg. Among them, 24 are well-known objects and the remaining 62 sources are unidentified. For the fully coincident sources, whenever possible, we analyzed color-color and hardness ratio diagrams and found that at least 3 of them display high-mass X-ray binary characteristics, making them potential microquasar candidates.