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Seminar
Speaker
Sreekanth Harikumar (Nicolaus Copernicus Astronomical Center, Poland)
Date & Time
Thu, 11 December 2025, 15:30 to 17:00
Venue
Feynman Lecture Hall
Resources
Abstract

Gravitational waves (GW) can be distorted by intervening massive structures, a phenomenon known as GW lensing. This effect provides a novel way into the nature of dark matter (DM) and the properties of dense star clusters. In this talk, I will present two complementary applications of GW lensing.
First, I will focus on long-duration, quasi-monochromatic GW signals from rapidly rotating, neutron stars - a promising yet undetected source of GWs. When microlensed by DM, these signals acquire a characteristic time-dependent amplification, known as the Paczyński curve. Using a Time-Domain F-Statistic framework, I will show how this microlensing imprint can serve as a  probe of the fundamental nature of dark matter.
In the second part, I will discuss the lensing of compact binary merger signals by globular clusters (GCs). Such lensing events may encode information about the internal dynamics of GCs, including their velocity dispersion. I will discuss how lensed GW events could be used as a complementary tool to study GC.

Zoom link:  https://icts-res-in.zoom.us/j/93555246640?pwd=puKgHnhiZOSERCADa8YvNbRF5qD3Hf.1
Meeting ID: 935 5524 6640
Passcode: 517664