LIGO may announce detection of merging neutron stars…

Speculation is running rampant about potential new discoveries of gravitational waves, just as the latest search wound down August 25.

Publicly available logs from astronomical observatories indicate that several telescopes have been zeroing in on one particular region of the sky, potentially in response to a detection of ripples in spacetime by the Advanced Laser Interferometer Gravitational-Wave Observatory, LIGO. These records have raised hopes that, for the first time, scientists may have glimpsed electromagnetic radiation — light — produced in tandem with gravitational waves. That light would allow scientists to glean more information about the waves’ source. Several tweets from astronomers reporting rumors of a new LIGO detection have fanned the flames of anticipation and amplified hopes that the source may be a cosmic convulsion unlike any LIGO has seen before.

“There is a lot of excitement,” says astrophysicist Rosalba Perna of Stony Brook University in New York, who is not involved with the LIGO collaboration. “We are all very anxious to actually see the announcement.”

An Aug. 25 post on the LIGO collaboration’s website announced the end of the current round of data taking, which began November 30, 2016. Virgo, a gravitational wave detector in Italy, had joined forces with LIGO’s two on August 1 (SN Online: 8/1/17). The three detectors will now undergo upgrades to improve their sensitivity. The update noted that “some promising gravitational-wave candidates have been identified in data from both LIGO and Virgo during our preliminary analysis, and we have shared what we currently know with astronomical observing partners.”

When LIGO detects gravitational waves, the collaboration alerts astronomers to the approximate location the waves seemed to originate from. The hope is that a telescope could pick up light from the aftermath of the cosmic catastrophe that created the gravitational waves — although no light has been found in previous detections.

LIGO previously detected three sets of gravitational waves from merging black holes (SN: 6/24/17, p. 6). Black hole coalescences aren’t expected to generate light that could be spotted by telescopes, but another prime candidate could: a smashup between two remnants of stars known as neutron stars. Scientists have been eagerly awaiting LIGO’s first detections of such mergers, which are suspected to be the sites where the universe’s heaviest elements are formed. An observation of a neutron star crash also could provide information about the ultradense material that makes up neutron stars.