| Name: | Gourav Kumawat |
| Affiliation: | Indian Institute of Science Education and Research Bhopal |
| Conference ID : | ASI2024_46 |
| Title : | Chandra and HST studies of the X-ray sources in the Globular Cluster NGC 362 |
| Authors : | Gourav Kumawat1,2, Craig O. Heinke2, Haldan N. Cohn3, Phyllis M. Lugger3 |
| Authors Affiliation: | 1 Indian Institute of Science Education and Research, Bhopal 462066, India
2 University of Alberta, Edmonton, AB T6G 2G7, Canada
3 Indiana University, 727 E. Third St., Bloomington, IN 47405, USA |
| Mode of Presentation: | Poster |
| Abstract Category : | Stars, Interstellar Medium, and Astrochemistry in Milky Way |
| Abstract : | Globular clusters (GCs) are dense stellar systems where frequent gravitational interactions between stars lead to various dynamical processes, including the formation of exotic binary star systems like millisecond pulsars (MSPs), cataclysmic variables (CVs), and low-mass X-ray binaries (LMXBs). In our analysis of the rich globular cluster NGC 362 using Chandra observations, 33 X-ray sources were found within 1' (equivalent to 1.2 half-mass radii) of the cluster centre. The brightest source (X1) exhibited blackbody-like emission, indicating that it is a quiescent low-mass X-ray binary, and a potential counterpart was identified in the sub-subgiant region. HST UV Globular Cluster Survey (HUGS) photometry was used to identify 15 potential optical/UV counterparts for these X-ray sources, including two background AGNs. No likely CVs were located, probably due to crowding in the core's optical filters. Nevertheless, the analysis predicted the presence of approximately 8 CVs among the detected X-ray sources. Additionally, three other sub-subgiants and two red straggler counterparts were identified, likely powered by coronal activity. Five potential coronally active binary counterparts were also found for three X-ray sources. Lastly, two intriguing counterpart candidates were observed, positioned to the red side of the red giant branch in V606 − I814, and shifted substantially to the blue side of the red giant branch in ultraviolet color-magnitude diagrams. These systems appeared to include a red giant with a complex evolutionary history and a prominent blue light source, potentially a blue straggler star (resembling an Algol-like system) or an accreting white dwarf (akin to a long-period CV or a symbiotic star). |
