Since October 9, 2022, all telescopes capable of contributing something to research have been participating in the observation of GRB 221009A… A gamma burst of extraordinary power, which has a hard time fitting into the boxes. A complex adventure, even if we are lucky enough to have high-performance tools!
At nearly 50 years, we missed it, or almost…
One flash to light them all
It was quickly nicknamed the BOAT: GRB 221009A became, on October 9, 2022, the “brightest of all time”, the brightest gamma-ray burst ever observed. Whether they are generated by two neutron stars colliding, by a star collapsing in on itself in a supernova or a black hole, it is generally necessary to quickly mobilize significant resources to locate and observe them… These phenomena can be extremely short. But last October, the complete opposite happened. Whether distant Voyager 1, Martian orbiters or other space observatories, 25 probes and satellites have detected it! The GRB 221009A gamma-ray burst, emitted about 2 billion years ago, hit our atmosphere with an intensity comparable to a small solar flare.
He doesn’t look like the others
If the gamma-ray burst was not long, the echo in other frequency bands continues to reach us, so since the detection of GRB 221009A, a large number of sensors have been turned towards it. Including Hubble and the James Webb telescope, which provide superb images… But not the most usable in this field. X-band emissions, for example (measured by the Swift observatory), showed an intensity ten times greater than “usual” gamma-ray bursts! And the differences do not stop there, a team from the University of Utah has shown, in a multi-frequency study, that the radio waves of this burst will still be present for several years by dint of echoes. On the other hand, to reach us, GRB 221009A has crossed many environments, in particular clouds of dust and gas in its own galaxy… And in ours! A fine analysis of the signal also allows to know more.
What is the origin of this gamma-ray burst?
Overall, laboratories around the world emphasize the difference between this burst and the others, especially since its origin is not yet unanimous: the models explain our measurements rather poorly. The icing on the cake, after two months of observation, we had to stop measuring GRB 221009A, for a very simple reason, which is that it was hidden from us by the Sun itself. The measurements did not resume (hopefully) until after January, and obviously have not yet been published. Visible, UV and infrared light emissions also show that the star at the source of this impressive wave of energy would not have transformed into a supernova… Even if for the first time on this scale, the small IXPE space telescope was able to observe the polarization of this burst (and subsequent emissions). All of the articles specially dedicated to GRB 221009A have been compiled in an edition of the “Astrophysical Research Letters” (peer-reviewed journal) published a few days ago, and this is one of the most more followed and studied in recent months in this scientific community. Researchers estimate that this is an event whose measurement occurrence is approximately once every 10,000 years…
Source : skyandtelescope.org
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