E-Paper
LIGO India waits on central govt approvals: IUCAA director
PUNE The proposal for LIGO India has reached many milestones, but further approvals are pending with the central government and as soon as the approvals come, work will begin,” said Professor Somak Raychaudhury, director, Inter University Centre for Astronomy and Astrophysics (IUCAA), during a webinar on Friday
PUNE The proposal for LIGO India has reached many milestones, but further approvals are pending with the central government and as soon as the approvals come, work will begin,” said Professor Somak Raychaudhury, director, Inter University Centre for Astronomy and Astrophysics (IUCAA), during a webinar on Friday.
LIGO-India is a collaboration between the LIGO Laboratory (operated by Caltech and MIT), and three Institutes in India: the Raja Ramanna Centre for Advanced Technology (RRCAT, in Indore), the Institute for Plasma Research (IPR in Ahmedabad), and the Inter-University Centre for Astronomy and Astrophysics (IUCAA, in Pune).
“The process of land acquisition is complete. Due to the pandemic, work has been delayed but talks are ongoing. During the lockdown, the physical work had stopped, but the science was ongoing,” said Raychaudhary.
After 48 collisions between black holes, and two collisions between neutron stars, the discovery of a new source of gravitational waves (GWs) by the LIGO Scientific Collaboration (LSC) is a major breakthrough, the webinar noted.
Scientists noted that this was the first confirmed detection of a pair of hybrid, neutron star-black hole collisions.
During the webinar, scientists shared that although indirect detections of black holes of stellar mass, which result from collapse of a dead star and supermassive black holes, which are central engines of massive galaxies, were found, it was not known until recently whether intermediate mass black holes (IMBH) can exist.
Archana Pai from IIT Bombay said that this was first detected on May 21, 2019 (event GW190521), and announced on September 2, 2020.
“This led to a hunt for IMBH binaries in the year-long data run of Advanced LIGO-Virgo detectors. The results were announced by LIGO-Virgo-Kagra (LVK) collaboration of GW detectors (LVK) on May 31, 2021. In addition to confirmation of the previous results, it led to a revised understanding of how rare such massive mergers are,” said Pai.
During the webinar, Dr Anupreeta More from IUCAA said that on May 13, this year, LVK announced the results of the search for lensing of GWs - the bending of GWs by gravity itself.
“So far there have been no promising lens candidates which is consistent with our expectations, but even the absence of detectable lensing effects has already improved our knowledge of the compact binary merger rate in the distant universe,” said Dr More.
Professor KG Arun from Chennai Mathematical Institute (CMI), Chennai, said that among the other science we can learn from observations of GWs, are tests for theories of gravity.
“High speed collisions of black holes/neutron stars are excellent test-beds for general relativity (GR) and Einstein’s theory of gravity. Results from current observing runs show no hint of GR violation which means Einstein is still right. But, analyses are still ongoing. Significant contributions from several Indian institutes in these efforts, and LIGO-India can play a crucial role in certain tests of GR which use data from multiple detectors,” said Arun.
