Researchers say light signal from space suggests merging black holes

Saturday, January 10, 2015

Artist's depiction of two supermassive black holes merging.
Image: NASA.

On Wednesday, George Djorgovski and collaborators reported in the journal Nature on an unusual light signal they say suggests two supermassive black holes are merging, a phenomenon never seen before, though theorized.

The discovery could clarify how black holes merge and galaxies evolve, and could also provide a better understanding of the so-called "final parsec problem" — the inability of theories to predict how, or even how quickly, the final phases of black hole mergers happen.

The team discovered the light coming from quasar PG 1302-102 in data from the Catalina Real-time Transient Survey (CTRS), which is able to study light sources from four fifths of the night sky using three ground-based US and Australian telescopes.

Coauthor and Caltech computational scientist Matthew Graham emphasized the final stages of these black hole mergers are not well understood.

Sine wave

Image: Geek3

CTRS has so far identified 20 quasars with similar signals, but Graham said this one is the best example because it has a clear signal that recurs about every five years, similar to a sine wave (see the 2D graph shown on the left).


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