Using an array of ground and space-based telescopes, including the NASA/ESA/CSA James Webb Space Telescope, NASA’s Fermi Gamma-ray Space Telescope, and NASA’s Neil Gehrels Swift Observatory, astronomers observed GRB 230307A, the second-brightest gamma-ray burst ever seen, which was caused by a neutron star merger. In the aftermath of the explosion, the researchers detected the heavy chemical element tellurium. Other elements such as iodine and thorium are also likely to be amongst the material ejected by the explosion, also known as a kilonova.
First detected by Fermi in March 2023, GRB 230307A is the second brightest gamma-ray burst observed in over 50 years of observations, about 1,000 times brighter than a typical gamma-ray burst that Fermi observes.
The event also lasted for 200 seconds, placing it firmly in the category of long duration gamma-ray bursts, despite its different origin.
“This burst is way into the long category. It’s not near the border. But it seems to be coming from a merging neutron star,” said Fermi team member Dr. Eric Burns, an astronomer at Louisiana State University.
The collaboration of many telescopes on the ground and in space allowed scientists to piece together a wealth of information about this event as soon as the burst was first detected.
It is an example of how satellites and telescopes work together to witness changes in the Universe as they unfold.
After the first detection, an intensive series of observations from the ground and from space, including with Swift, swung into action to pinpoint the source on the sky and track how its brightness changed.
These observations in the gamma-ray, X-ray, optical, infrared, and radio showed that the optical/infrared counterpart was faint, evolved quickly, and became very red — the hallmarks of a kilonova.
“This type of explosion is very rapid, with the material in the explosion also expanding swiftly,” said Dr. Om Sharan Salafia, an astronomer at the INAF – Brera…
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