(ORDO NEWS) — In a groundbreaking study published in the journal Nature Astronomy , scientists from the Purple Mountains Observatory (PMO) of the Chinese Academy of Sciences and the Italian National Institute of Astrophysics presented a new method for measuring moderately saturated sources with the Ultraviolet Optical Telescope on board the Swift (Swift/UVOT) satellite. This innovative technique allowed GRB 220101A to be identified as the most energetic ultraviolet/optical flare ever detected.
Gamma-ray bursts (GRBs) are known as the most powerful explosions in the Universe, with their pulsed emission occurring predominantly in the soft gamma-ray range and lasting only a short time. After the first explosion, an afterglow consisting of X-ray, optical and radio waves is observed, which can persist for several weeks or even years.
In 2008, GRB 080319B set a record for ultraviolet/optical emission that was so bright that it could be observed with the naked eye from a dark room. The optical flare emission from this burst provided valuable information about the activity of the central engine. However, GRB 220101A has now surpassed this record.
On New Year’s Day 2022, the Swift satellite detected a new burst, GRB 220101A, at a redshift of 4.618. At such a high redshift, the observed optical photons were in the ultraviolet region and experienced significant absorption. As a result, the flux of its own radiation turned out to be approximately 100 times higher than observed. Just 79 seconds after the flare, Swift/UVOT conducted a rapid 150-second observation in white-band event mode.
Using photometric analysis with high temporal resolution, the researchers discovered a rapid evolution of the flow. It is noteworthy that at the time of the peak, the UVOT telescope was already moderately saturated. To accurately measure the flux, the scientists developed a processing method based on the telescope’s point distribution function, which has proven to be reliable.
“After appropriate corrections for distance and absorption, the ultraviolet/optical absolute magnitude of GRB 220101A reached -39.4, making it the only source to date with an absolute magnitude brighter than -39,” said Professor FAN Yizhong of PMO, author -Research Correspondent This discovery is the first time an extremely energetic ultraviolet/optical flare has been detected using a space telescope.
The luminosity of GRB 220101A is approximately 400 quadrillion times that of the Sun, breaking the previous 14-year record held by GRB 080319B. This remarkable discovery not only highlights the diversity of physical reasons for the occurrence of superbright optical-ultraviolet bursts, but also suggests a new astrophysical process.
Looking ahead, the Sino-French SVOM (Space Variable Objects Monitor) satellite, scheduled to launch in early 2024, is expected to further deepen our understanding of these phenomena by detecting extremely energetic ultraviolet/optical flares at even higher redshifts.
These groundbreaking studies open up new possibilities for studying and understanding the most powerful explosions in the Universe. With advancements in technology and upcoming missions, scientists are poised to uncover even more secrets hidden in these cosmic phenomena.
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