{"id":15393,"date":"2024-04-08T14:16:19","date_gmt":"2024-04-08T12:16:19","guid":{"rendered":"https:\/\/igfae.usc.es\/~igfae-old\/?p=15393"},"modified":"2024-04-08T14:47:03","modified_gmt":"2024-04-08T12:47:03","slug":"gw-230529-igfae","status":"publish","type":"post","link":"https:\/\/igfae.usc.es\/~igfae-old\/gw-230529-igfae\/","title":{"rendered":"An intriguing gravitational wave: IGFAE participates in the detection of an unusual collision of two cosmic objects"},"content":{"rendered":"

On 29 May 2023, a detector from LIGO collaboration<\/a> located in Livingston, (Lousiana, USA), observed a signal coming from 650 million light-years away. After nearly a year of analysis, the results, presented last Friday at the monthly meeting of the American Physical Society, were intriguing: the mass of one of the two compact objects whose collision generated this gravitational wave is in a nearly unexplored range: too heavy to be a neutron star, but much lighter than any previously known black hole.<\/p>\n

For now, the LIGO-Virgo-Kagra (LVK) collaboration, consisting of nearly 3 000 scientists from the three observatory networks involved in gravitational-wave detection, has not been able to reveal the nature of this object. Only future detections of similar events, especially those accompanied by bursts of electromagnetic radiation, could hold the key to solve this cosmic mystery.<\/p>\n

A team of researchers from the Instituto Galego de F\u00edsica de Altas Enerx\u00edas (IGFAE), a joint centre of the University of Santiago de Compostela and the Xunta de Galicia, participated in this analysis. “\u201cOur work at IGFAE has improved the search methods used by LVK for binary merger signals like GW230529, and we are excited to see such an interesting result already. Whenever detectors or analysis methods are upgraded, there is a higher chance that we will see something new and surprising\u201d, says Dr Thomas Dent, leader of the gravitational-wave research programme at the IGFAE.<\/p>\n

The mass gap between neutron stars and black holes<\/strong><\/h5>\n

Both neutron stars and black holes are extremely dense ‘compact’ objects, originating from the collapse and explosion of massive stars. Even before the first direct observation of gravitational waves in 2015, each of these objects was detected in a different way: while the masses of neutron stars were determined by radio observations, the masses of black holes were calculated from X-ray data.<\/p>\n

Analysis of the signal GW230529 shows that it came from the merger of two compact objects, one with a mass between 1.2 to 2 times that of our Sun and the other slightly more than twice as massive. While the gravitational-wave signal does not provide enough information to determine with certainty whether these compact objects are neutron stars or black holes, it seems likely that the lighter object is a neutron star and the heavier object a black hole. Scientists in the LVK Collaboration are confident that the heavier object is within the mass gap.<\/p>\n

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Gravitational-wave observations have now provided almost 200 measurements of compact-object masses. Of these, only one other merger may have involved a mass-gap compact object \u2013 the signal GW190814 came from the merger of a black hole with a compact object exceeding the mass of the heaviest known neutron stars and possibly within the mass gap.<\/p>\n

While previous evidence for mass-gap objects has been reported both in gravitational and electromagnetic waves, this system is especially exciting because it\u2019s the first gravitational-wave detection of a mass-gap object paired with a neutron star. It also implies a higher chance of seeing electromagnetic radiation emitted by neutron-star–black-hole mergers in future,\u201d says Dr. Sylvia Biscoveanu from Northwestern University.<\/p>\n