Ajit Kumar Mehta (Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Potsdam, Germany)
Date & Time
Wed, 11 May 2022, 11:00 to 12:30
Online and Madhava Lecture Hall

The formation mechanism, evolutionary history and mass function of intermediate mass black holes (IMBHs) are still not well known, as it is very difficult to observe them and measure their masses in the electromagnetic window. In this work, we explore the possibility to measure the source parameters of IMBH binaries via gravitational waves in the upcoming O4/O5 LIGO-Virgo observation. We perform parameter estimation (PE) on a large set of non-precessing IMBH binaries and show that the primary source mass can typically be measured with accuracy 10~40%, far better than what might be possible by electromagnetic observations of such binaries.  A particular subset of IMBH population in the mass range ~ 50-130Msun is prohibited from the stellar evolution theory due to what is known as the pair production instability. The limits of this mass range, however, are subject to uncertainties in the nuclear reaction rates. In this work, we also perform evolution of massive Helium stars using the MESA stellar evolution code to understand the susceptibility of the mass gap range to plausible changes in these nuclear rates. Having established the mass gap range, we perform PE study and show that upcoming LIGO-Virgo detectors are capable of robustly identifying binaries with components lying in the mass gap.

Zoom link:
Meeting ID:  885 2703 5879
Passcode: 112212