Scientists detect gravitational waves from black holes devouring neutron stars

Scientists have discovered gravitational waves created by black hole and neutron star mergers for the first time. In January 2020, a team of researchers discovered two gravitational wave incidents in a 10-day period from distances of more than 900 million light-years. The results of the research were reported in the Astrophysical Journal Letters journal. The Center for Computational Relativity and Gravitation (CCRG) at Rochester Institute of Technology-assisted in identifying crucial aspects of the merger occurrences.

Anjali Yelikar, an Indian PhD student in astrophysical sciences and technology, was substantially involved in the research. To find the mass, spin, distance from Earth, and position in the sky of the black holes and neutron stars involved, she used parameter estimation code developed by Associate Professor Richard O'Shaughnessy and alumnus Jacob Lange '18 MS (astrophysical sciences and technology), '20 PhD (astrophysical sciences and technology).

Scientists detect gravitational waves from black holes

Yelikar said, "It's a real dream come true to be a part of a discovery like this." She added, "I was an undergraduate student when LIGO announced the first gravitational wave detection in 2016. It's amazing to see how far the science has come and I am excited to see what new developments await as the scientific community develops more sensitive detectors."

Due to the Coronavirus pandemic in March 2020, the year-long third observing run was cut short by a month, and the fourth is set to begin in the summer of 2022, bringing more advanced detectors into the fold.

While the mergers announced today provide hints about their origins, scientists hope to find more confirmation in subsequent observing runs. Two main theories suggest how neutron stars and black holes could merge—one starting with two stars already orbiting each other and the other starting with unrelated supernova explosions—and while the mergers announced today provide hints about their origins, scientists hope to find more confirmation in subsequent observing runs.

"These elusive systems have long been missing from astronomers' family portrait of compact binaries," said O'Shaughnessy. "Now that we see the whole family, we can use this portrait to try to understand their relationships and lineage. For example, at least one of the neutron stars in these objects is relatively big, compared to neutron stars found before. That may be a clue into how cosmic explosions work and how these objects form."

Gravitational waves in black holes

Despite observations from several observatories, scientists were unable to detect electromagnetic wave equivalents to the gravitational waves created by the events. However, scientists will keep an eye out for this throughout future observations.

Yosef Zlochower, an associate professor in the School of Mathematical Sciences who develops simulations used to compare against gravitational-wave signals, noted, "This discovery is very exciting, not only because it confirms the existence of black-hole-neutron-star binaries, but also because such binaries are potential sources of extremely intense gamma-ray bursts. This leads to the real possibility of future combined gravitational-wave and electromagnetic observations of these sources."

Professor John Whelan, the RIT group's primary investigator in the LIGO Scientific Community, commented, "With this observation of gravitational waves from yet another type of astrophysical system, the LIGO, Virgo and now KAGRA collaborations continue to broaden the field of gravitational-wave astronomy. We look forward to furthering discoveries as we analyze data from this and future observing runs."

(with inputs from ANI)

Picture Credit: ANI