LIGO detects gravitational waves of largest black hole merger yet
The LIGO gravitational wave detector, spread across several continents, successfully detected the largest black hole merger yet on November 23, 2023.
The two black holes that merged were approximately 100 and 140 times the mass of the Sun. In addition to their high masses they are also rapidly spinning, making this a uniquely challenging signal to interpret and suggesting the possibility of a complex formation history. “This is the most massive black hole binary we’ve observed through gravitational waves, and it presents a real challenge to our understanding of black hole formation,” says Professor Mark Hannam, from Cardiff University and a member of the LIGO Scientific Collaboration. “Black holes this massive are forbidden through standard stellar evolution models. One possibility is that the two black holes in this binary formed through earlier mergers of smaller black holes.”
To date, approximately 300 black-hole mergers have been observed through gravitational waves, including candidates identified in the ongoing O4 run. Until now the most massive confirmed black-hole binary was the source of GW190521, with a much smaller total mass of “only” 140 times that of the sun.
As noted by the press release as well as this news article, present theories of stellar evolution say that these black holes could not have come from single stars, which are predicted to never be this massive. It is posited that each black hole might have formed from earlier mergers, but there is also a lot of uncertainty in the data. To quote the release again: “Extracting accurate information from the signal required the use of theoretical models that account for the complex dynamics of highly spinning black holes.”
That this detection was almost two years ago and only announced now makes me wonder if the timing of the announcement has more to do with lobbying and less to do with science. Trump’s proposed budget eliminates the U.S. funding portion for this project, and it is standard operating procedure for such projects to suddenly announce big discoveries timed to correspond to when Congress is considering the budget.
The LIGO gravitational wave detector, spread across several continents, successfully detected the largest black hole merger yet on November 23, 2023.
The two black holes that merged were approximately 100 and 140 times the mass of the Sun. In addition to their high masses they are also rapidly spinning, making this a uniquely challenging signal to interpret and suggesting the possibility of a complex formation history. “This is the most massive black hole binary we’ve observed through gravitational waves, and it presents a real challenge to our understanding of black hole formation,” says Professor Mark Hannam, from Cardiff University and a member of the LIGO Scientific Collaboration. “Black holes this massive are forbidden through standard stellar evolution models. One possibility is that the two black holes in this binary formed through earlier mergers of smaller black holes.”
To date, approximately 300 black-hole mergers have been observed through gravitational waves, including candidates identified in the ongoing O4 run. Until now the most massive confirmed black-hole binary was the source of GW190521, with a much smaller total mass of “only” 140 times that of the sun.
As noted by the press release as well as this news article, present theories of stellar evolution say that these black holes could not have come from single stars, which are predicted to never be this massive. It is posited that each black hole might have formed from earlier mergers, but there is also a lot of uncertainty in the data. To quote the release again: “Extracting accurate information from the signal required the use of theoretical models that account for the complex dynamics of highly spinning black holes.”
That this detection was almost two years ago and only announced now makes me wonder if the timing of the announcement has more to do with lobbying and less to do with science. Trump’s proposed budget eliminates the U.S. funding portion for this project, and it is standard operating procedure for such projects to suddenly announce big discoveries timed to correspond to when Congress is considering the budget.