B.S. Sathyaprakash - Bert Elsbach Professor of Physics - Faculty
- IGC Executive Committee
Office: 312 Whitmore Laboratory
Address: Department of Physics
Professor Physics and Professor of Astronomy & Astrophysics, Pennsylvania State University, University Park, USA 2016
School of Physics and Astronomy, Cardiff University, Cardiff, UK Professor of Gravitational Physics 2003
Associate Director, Institute for Gravitation and the Cosmos, Pennsylvania State University, University Park, USA 2017-2021
Lecturer, Senior Lecturer & Reader, Cardiff University, Cardiff, UK Professor of Gravitational Physics, UK, 1996-2003
Visiting Professor, California Institute of Technology, Pasadena, USA, 1996
Assistant Professor, Inter-University Centre for Astronomy & Astrophysics, Pune, India 1993-1995
Postdoctoral Fellow, International Centre for Theoretical Physics, Trieste, Italy 1992
Postdoctoral Fellow, Inter-University Centre for Astronomy & Astrophysics, Pune, India 1989-1991
Council for Scientific & Industrial Research, Postdoctoral Fellow, Indian Institute of Science, Bangalore, India 1988
1987 PhD, Theoretical Physics, Indian Institute of Science, Bangalore, India
1981 MSc, Physics, Indian Institute of Technology, Madras, India
1979 BSc, Major in Physics, Chemistry and MathematicsBangalore University, Bangalore, India
"Comparison of post-Newtonian templates for compact binary inspiral signals in gravitational-wave detectors." Phys. Rev. D 80 (2009)
"Improved filters for gravitational waves from inspiralling compact binaries." Phys. Rev. D 57 (1998)
"Observation of Gravitational Waves from a Binary Black Hole Merger." Phys. Rev. Lett. 116 6 (2016)
"GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2." Phys. Rev. Lett. 118 22 (2017)
"GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral." Phys. Rev. Lett. 119 16 (2017)
"Tests of General Relativity with GW170817." Phys. Rev. Lett. 123 1 (2019)
"Parametrized tests of post-Newtonian theory using Advanced LIGO and Einstein Telescope." Phys. Rev. D 82 (2010)
"Matched filtering of gravitational waves from inspiraling compact binaries: Computational cost and template placement." Phys. Rev. D 60 (1999)
"Choice of filters for the detection of gravitational waves from coalescing binaries." Phys. Rev. D 44 (1991)
"Scientific Objectives of Einstein Telescope." Class. Quant. Grav. 29 (2012)
The largest catalog of gravitational wave events ever assembled has been released by an international collaboration that includes members of the Institute for Gravitation and the Cosmos. Gravitational waves are ripples in space time produced as aftershocks of huge astronomical events, such as the collision of two black holes. Using a global network of detectors, the research team identified 35 gravitational wave events, bringing the total number of observed events to 90 since detection efforts began in 2015.
The LIGO-Virgo-KAGRA Scientific Collaboration, has announced the discovery of two neutron star-black hole mergers in the data from the third observing run, separated by 10 days on 5 and 15 January 2021. The IGC LIGO group played a crucial role in this new discovery: Both of these mergers were detected as part of real-time gravitational wave processing conducted by members of the IGC LIGO group. LIGO and Virgo detectors have previously observed the merger of dozens of binary black holes and two binary neutron stars. Neutron star-black hole binaries were believed to exist but this is the first time ever astronomers have witnessed such a phenomena. In each case, the neutron star was likely swallowed whole by its black-hole partner without emitting any electromagnetic radiation. The system observed on January 5 had companion masses of 1.5 solar mass for the neutron star and 5.6 solar mass for the black hole, while the one observed on January 15 had masses 1.9 solar mass for the neutron star and 8.7 solar mass for the black hole. Both the systems came from roughly a distance of 300 Mpc. The details of the announcement can be found in the Penn State News Article.
Chad Hanna, associate professor of physics and of astronomy and astrophysics; B.S. Sathyaprakash, Elsbach Professor of Physics and Professor of Astronomy and Astrophysics; and graduate students Rebecca Ewing, Rachael Huxford and Divya Singh discuss discoveries made in the third LIGO-Virgo run that increased the number of observed binary coalescences from 11 to 50.
The merging black holes being roughly 85 and 66 times as heavy as our sun, are among the heaviest ones seen yet. The LIGO group at PSU played a significant role in the observation of this very short and difficult to detect signal which lasted for about one tenth of a second. The remnant produced by the merger is as heavy as about 142 times the mass of our sun which places it in the category of intermediate-mass black holes, an elusive type of heavy black holes that had not been observed directly so far. Being heavier than the black holes observed which have masses comparable to our sun, but less heavy than the supermassive black holes that occupy the centres of galaxies, these intermediate-mass black holes and their formation methods are not well understood by astrophysicists. In fact this discovery is also unusual because it questions existing astrophysical models of black hole formation and stands to open new doors in our understanding of these objects.
On August 14, 2019, the two Advanced LIGO detectors in the US, at Hanford, Washington and Livingston, Louisiana, and the Advanced Virgo detector in Cascina, Italy, observed a gravitational wave signal produced by the inspiral and merger of two compact objects - one, a black hole, and the other of undetermined nature. The mass measured for the lighter compact object makes it either the lightest black hole or the heaviest neutron star ever discovered in a system of two compact objects, but we can’t be sure which it is. This is also the most asymmetric system observed in gravitational waves as of now. This event was detected in real time by the GstLAL inspiral pipeline which is developed and operated largely by the LIGO group at Penn State.
Gravitational waves detected on April 25, 2019, by the LIGO Livingston Observatory were likely produced by a collision of two neutron stars, according to a new study by an international team including Penn State researchers. IGC members Patrick Godwin, Ryan Magee, B. Sathyaprakash and Surabhi Suchdev explain why this discovery is so exciting. This detection was made possible by the GSTLAL online software developed by faculty and postdocs at the Institute for Gravitation and the Cosmos. The total mass of the binary is significantly larger than all such systems we know in our galaxy and challenging astrophysical models of the formation of binary black holes.
Two new probable gravitational waves — ripples in the fabric of spacetime caused by cataclysmic cosmic events and first predicted by Albert Einstein over 100 years ago — have been detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo observatory in Italy in the first weeks after the detectors were updated. The IGC team of LIGO scientists, led by Chad Hanna, played a critical role.
B. Sathyaprakash has been elected Fellow of the International Society on General Relativity and Gravitation
B. Sathyaprakash has been elected Fellow of the International Society on General Relativity and Gravitation “for his wide-ranging contributions to all aspects of theoretical investigations of gravitational waves, outstanding service to the international gravitational community, and for his leadership in shaping the future of the field through third-generation detectors both in Europe and the US.”