Free Meson Seminars

Probing neutron star mergers with gravity and light

by Dr. Soumi De (Los Alamos National Laboratory)

Thursday, July 22, 2021 from to (Asia/Kolkata)
at Zoom
Description Please contact rishi(at)theory(dot)tifr(dot)res(dot)in for the zoom meeting id and the password for this seminar.

Observations of black hole and neutron star mergers in the era of multimessenger astronomy has enabled us to solve several problems in physics. LIGO-Virgo’s first observations of a binary neutron merger, GW170817, was also the first ever event observed by both gravitational waves and light. Gravitational waves from compact binary coalescences encode information about physical properties of the component objects---such as masses, spins, and tidal deformabilities---in the source binary system. Measuring these parameters from neutron star merger observations can help us address several long-standing questions such as---what is the nature of matter at highest densities in the observable universe? The merger of two neutron stars or a neutron star and a black hole typically leads to the formation of a post-merger accretion disk. Outflows from such disks are a major source of r-process nuclei, fueling electromagnetic transients such as kilonovae. With gravitational-wave detectors starting to sample the neutron star merger parameter space, it is necessary to create disk models spanning the variety of neutron star binaries, that can be used to study engines triggering electromagnetic transients from future observations. In this talk, I will review LIGO-Virgo’s first observations of a binary neutron merger, GW170817, and discuss what we have learned about properties of neutron stars from the spectacular multimessenger observations of the event. I will then describe the variety of neutron star post-merger accretion disks, their outflows, and r-process yields with the help of three-dimensional general-relativistic magnetohydrodynamic (GRMHD) simulations. Finally, I will point out what future observations might tell us.