Webinar

Astrophysics with multiple messengers: Photons and Gravitational-waves

Speaker: Kunal P Mooley (Caltech, California)

Date and time
Webinar link
Zoom Meeting ID: 832 2942 9038 Passcode: 364288
Venue
Auditorium

Abstract

The detection of gravitational waves (GWs) and electromagnetic (EM) waves from binary neutron star merger GW170817 delivered a scientific bonanza in fields as wide-ranging as gravitational and nuclear physics, relativistic jets and cosmology, and has ushered a new era of multi-messenger astronomy. The tidally stripped material (outflows) was responsible for the EM radiation. The thermal (blackbody-like) kilonova component of this radiation, which arose from the r-process nucleosynthesis and lasted for a few weeks post-merger, gave insight into the mass and composition of the Newtonian ejecta. The non-thermal (synchrotron) afterglow component of the radiation, which was monitored extensively at radio wavelengths and lasted for more than three years, probed the energy and morphology of the relativistic ejecta (jet). Importantly, the compact radio source associated with GW170817 was seen to move in the sky, implying superluminal motion of the relativistic jet. The EM and GW (multi-messenger) data together gave precise constraints on the geometry of the progenitor binary system and facilitated a measurement of the Hubble constant. Although an unprecedented event, GW170817 represents only an initial exploration of a rich scientific landscape. The upcoming science runs of the LIGO, Virgo and KAGRA GW detectors (and especially after the addition of the LIGO-India detector in 2025) will deliver several binary neutron star and neutron star-black hole mergers every year, and the EM counterparts of these events will further our understanding of binary stellar evolution, physics of jet launching, r-process chemical enrichment, neutron star equation of state and cosmological expansion of the Universe. The advent of the third generation of GW detectors (like the Cosmic Explorer and Einstein Telescope, expected to operate in 2035+) and next-generation EM facilities (like the SKA, ngVLA, TMT, Daksha and Athena) will facilitate the studies of neutron star mergers substantially distant in space and time, when the Universe was much younger.

 

 

Short Biography
Kunal Mooley is an astrophysicist with research interests in gravitational-wave multi-messenger astronomy, compact objects (black holes, neutron stars, white dwarfs), astrophysical jets, astronomical surveys and techniques. His research relies on observations from a wide suite of telescopes such as the Karl G. Jansky Very Large Array (VLA), Very Long Baseline Array, Hubble Space Telescope Chandra and Keck. His recent work has offered key insights into white dwarfs and black holes harboring jets, the physics of neutron star mergers, enabled precision cosmology using gravitational wave sources, and probing the population of compact objects in the Galactic Center. Kunal is curently the co-lead of the JAGWAR program, which is a worldwide collaboration, set up to systematically study the afterglows of neutron star mergers, and co-chair of the VLA Sky Survey implementation commmittee. Kunal obtained his Ph.D. in Astrophysics in 2015 from Caltech, where he discovered new phase space of radio transient phenomena by implementing a new observing mode (On-the-Fly Mosaicking) on the VLA. In 2015, Kunal moved to the University of Oxford as a Hintze Fellow to study relativistic jets in accreting black holes, neutron stars and white dwarfs. From 2018-2020 he was a Jansky Fellow at the National Radio Astronomy Observatory and Caltech, advancing the field of multi-messenger astronomy. In 2021 Kunal took up a long-term position at Caltech and along with astrophysics, he now works on interdisciplinary proects related to cognition and consciousness. Outside of research, Kunal finds great interest in all kinds of sports and performing arts.