This artists impression reveals a kilonova produced by two colliding neutron stars. While studying the after-effects of a long gamma-ray burst (GRB), 2 independent groups of astronomers utilizing a host of telescopes in space and in the world have uncovered the unexpected hallmarks of a kilonova, the gigantic surge activated by clashing neutron stars. Credit: NOIRLab/NSF/AURA/ J. da Silva/Spaceengine
The NASA Neil Gehrels Swift Observatory, whose Mission Operations Center is situated at Penn State University, found a blast of high-energy light from a galaxy around 1 billion light-years away on December 11, 2021. The occasion, which was likewise selected up by the Fermi Gamma-ray Space Telescope, calls into question what was previously believed to be settled science worrying gamma-ray bursts (GRBs), the most energetic surges in the cosmos.
” It was something we had actually never ever seen prior to,” stated Simone Dichiara, assistant research teacher of astronomy and astrophysics at Penn State and member of the Swift team. “We understood it wasnt related to a supernova, the death of a massive star since it was too close. It was an entirely different sort of optical signal, one that we connect with a kilonova, the explosion triggered by colliding neutron stars.”
The Swift team was able to quickly determine the surges place, in the constellation Boötes, allowing other facilities to rapidly react with follow-up observations. Their observations have supplied the earliest look yet at the first phases of a kilonova, according to a NASA release. Their findings were just recently published in the journal Nature.
While studying the after-effects of a long gamma-ray burst (GRB), 2 independent groups of astronomers using a host of telescopes in space and on Earth have uncovered the unforeseen hallmarks of a kilonova, the enormous surge set off by clashing neutron stars. It was a completely different kind of optical signal, one that we associate with a kilonova, the surge activated by colliding neutron stars.”
Researchers previously understood long GRBs, which last a couple of seconds to one minute, as forming when a supermassive star explodes as a supernova. Short GRBs, which last less than 2 seconds, were previously thought to just occur when two compact objects– like two neutron stars or a neutron star and a black hole– clash to form a kilonova.
Gamma-ray bursts been available in two varieties: long and short. Scientists previously understood long GRBs, which last a couple of seconds to one minute, as forming when a supermassive star takes off as a supernova. Brief GRBs, which last less than 2 seconds, were formerly believed to just take place when two compact objects– like 2 neutron stars or a neutron star and a black hole– collide to form a kilonova.
The revelation that a kilonova might trigger a long gamma-ray burst rewrites the decades-long paradigm of cosmic surges: that long GRBs are strictly the signature of the death of enormous stars, Dichiara described. The discovery suggests not all long GRBs are made by supernovae, some are produced by the merger of neutron stars.
” This occasion was a game-changer that revealed to us how our reputable knowledge of the universe was in fact only a incomplete and partial view,” stated Eleonora Troja, an astronomer at the University of Rome Tor Vergata and lead author on the paper. “This outcome was difficult to absorb initially and we invested months trying to find out alternative descriptions, however in the end, this is the only one that works well. We have been studying GRBs for decades, it is incredible to see how the universe can shock us in the most unforeseen ways.”
Referral: “A close-by long gamma-ray burst from a merger of compact items” by E. Troja, C. L. Fryer, B. OConnor, G. Ryan, S. Dichiara, A. Kumar, N. Ito, R. Gupta, R. T. Wollaeger, J. P. Norris, N. Kawai, N. R. Butler, A. Aryan, K. Misra, R. Hosokawa, K. L. Murata, M. Niwano, S. B. Pandey, A. Kutyrev, H. J. van Eerten, E. A. Chase, Y.-D. Hu, M. D. Caballero-Garcia and A. J. Castro-Tirado, 7 December 2022, Nature.DOI: 10.1038/ s41586-022-05327-3.
The research study was funded by the European Research Council through the Consolidator grant BHianca and by the National Science Foundation.
