A global team involving ICUB-Tech researchers detects a type of unidentified astronomical object
Researchers from the international collaborations LIGO and Virgo, in which the Institute of Cosmos Sciences of the UB (ICCUB) takes part under the coordination of Jordi Portell –co-director of the ICCUB Technology Unit, based in the Barcelona Science Park– have announced the discovery of an object of 2.6 solar masses, placing it firmly into so-called mass gap. That is an interval between the mass of the heaviest neutron star and the lightest blackhole, from which there were no observations yet.
When the most massive stars die, they collapse under their own gravity and leave behind black holes; when stars that are a bit less massive die, they explode in supernovas and leave behind dense, dead remnants of stars called neutron stars. For decades, astronomers have been puzzled by a the so-called mass gap, that lies between neutron stars and black holes: the heaviest known neutron star is no more than 2.5 times the mass of our sun, or 2.5 solar masses, and the lightest known black hole is about 5 solar masses.
Now, in a new study from the Laser Interferometer Gravitational-Wave Observatory (LIGO) in USA and the Virgo Collaboration in Europa, scientists have announced the discovery of an object of 2.6 solar masses, placing it firmly in this mass gap, an interval between the mass of the heaviest neutron star and the lightest blackhole, according to current astrophysical models.
This finding, carried out thanks to the three detectors of gravitational waves with which both collaborations work, has been published in The Astrophysical Journal Letters (DOI: https://doi.org/10.3847/2041-8213/ab960f).
“Thanks to the improvements to be applied in EGO-Virgo observatory in Pisa (Italy), in the data analysis techniques and dynamic astrophysical models, —areas where ICCUB plays an important role— we expect to detect more events like this, which allow us to understand the exact nature of these intriguing astrophysical objects”, notes Jordi Portell, coordinator of the Virgo group at ICCUB-Tech Unit, based in the Barcelona Science Park.
The nature of the object, detected in the gravitational event tagged as GW190814, is still a mystery. This event happened about 800 million years ago, when the object merged with a blackhole of about 23 solar masses. When this happened, it created a final blackhole of about 25 times the mass of the Sun. The merge generated an intense gravitational wave the three instruments of the network detected on August 14, 2019.
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