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Research Seminar: Unveiling Interaction in Globular Clusters and their Impact on Compact Binary Evolution

Speaker Dr. Kwangmin OH
Affiliation Michigan State University & Chungnam National University
Date July 27, 2023 (Thursday)
Time 3:00 p.m.
Venue Room 522, Chong Yuet Ming Physics Building, The University of Hong Kong

Abstract

Our study presents a comprehensive investigation of the dynamical influence on the compact binaries, specifically millisecond pulsars (MSPs) and cataclysmic variables (CVs), in globular clusters (GCs). We examine the properties of MSPs in core-collapsed (CCed) and non-core-collapsed (Non-CCed) GCs, finding that MSPs in CCed GCs generally rotate slower than those in Non-CCed GCs. This is attributed to enhanced secondary encounters in CCed GCs, leading to a prevalence of isolated MSPs and fewer X-ray binaries in these clusters. In comparing the radio luminosities of MSPs in GCs, we found that those reside in CCed GCs are significantly more luminous in L-band. Together with the indication of their broader pulse profiles, this suggests the magnetic field structure of the MSPs in CCed and Non-CCed GCs are different.
In parallel, we explore the dynamical formation of CVs in GCs using a Monte Carlo code. Our findings identify three distinct groups based on core density evolution over time, with a significant fraction of bright CVs emerging during the core contraction phase and notable disparities in X-ray luminosity across the groups are revealed, underscoring the need for detailed theoretical modeling of CV formation and evolution in various dynamical environments.
Our research provides new insights into the dynamical influence on the evolution of compact binaries in GCs, highlighting the need for further investigation into the emission geometry of MSPs as well as the formation and evolution of CVs in diverse dynamical environments.
 

Biography

Dr Kwangmin earned his Bachelor, Master, and PhD degrees in Astronomy from Chungnam National University (CNU) He is moving to Michigan State University for postdoctoral research. His research interests are in high-energy astrophysics, particularly with regards to the study of compact objects within globular clusters. Beyond his individual research, he is also a member of the LIGO-VIRGO-KAGRA collaboration, contributing to advancements in gravitational wave research.

Anyone interested is welcome to attend.