Scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) – an international observatory operated by the US National Science Foundation’s National Radio Astronomy Observatory (NRAO) – have recorded for the first time millimeter-wavelength light from a fiery explosion. Merger of a neutron star with another star. The team also confirmed that this flash of light is one of the most energetic short-period gamma-rays ever observed, leaving behind one of the brightest afterglows on record. The research results will be published in the upcoming edition of The Astrophysical Journal Letters,
Gamma-ray bursts (GRBs) are the brightest and most energetic bursts in the universe, capable of emitting more energy in just a few seconds than our Sun emits in its entire lifetime. GRB 211106A belongs to a GRB subclass known as short-lived gamma-ray burst, These explosions – which scientists believe are responsible for the formation of the heaviest elements in the universe, such as platinum and gold – result from the catastrophic merger of a binary star system with a neutron star. “These mergers are caused by gravitational wave radiation that removes energy from the orbit of binary stars, causing the stars to move toward each other,” said Tanmay Laskar, who will soon be an assistant professor of physics and astronomy. will start work. University of Utah. “The jets move close to the speed of light with the resulting explosion. When one of these jets is pointed at Earth, we observe a short pulse of gamma-ray radiation, or a short duration GRB.”
A short duration GRB usually lasts only a few tenths of a second. The scientists then look for an afterglow, an emission of light caused by the jet’s interaction with the surrounding gas. Still, they are difficult to detect; Only half a dozen short duration GRBs have been detected. radio wavelength, and so far none had been detected in millimeter wavelengths. Lasker, who led the research as an Excellence Fellow at Radboud University in the Netherlands, said the difficulty lies in the extreme distance to GRBs and the technical capabilities of the telescopes. “Short-period GRB afterglows are very bright and energetic. But these outbursts occur in distant galaxies, meaning the light from them may be too short for our telescopes on Earth. Prior to ALMA, the Millimeter Telescope of the Afterglow were not sensitive enough to detect.”
About 20 billion light years away from Earth, GRB 211106a is no exception. The light of this short-duration gamma-ray burst was so faint that the explosion was seen in early X-ray observations with NASA’s Neil Gehrels Swift Observatory, host galaxy That wavelength was undetectable, and scientists had not been able to determine where the explosion was coming from. “The afterglow light is essential to figure out which galaxy the explosion comes from and to learn more about the explosion itself. Initially, when only the X-ray equivalent was discovered, astronomers thought this explosion was Could come from a nearby galaxy.” A significant amount of dust in the region obscured the object from detection in optical observations with the Hubble Space Telescope, Lasker said.
Each wavelength added a new dimension to scientists’ understanding of GRBs, and the millimeter, in particular, was crucial to uncovering the truth about the explosion. “Hubble observations revealed an uncharacteristic region of galaxies. The unique sensitivity of ALMA allowed us to pinpoint the location of the GRB in that region with much greater precision, and it turned out to be in another faint galaxy, which is further away.” That, in turn, means that this short-duration gamma-ray burst is much more powerful than we thought, making it the brightest and most energetic on record,” Lasker said.
Wen-Fi Fong, assistant professor of physics and astronomy at Northwestern University, said, “This short gamma-ray burst was the first time we tried to observe such an event with ALMA. It was fantastic to catch this event shining so brightly. After many years of observing these explosions, this surprising discovery opens up a new field of study, as it allows us to see many of these with ALMA. inspire, and others Telescope arrays, in the future.”
“These observations are spectacular on many levels,” said NRAO/ALMA National Science Foundation Program Officer Joe Pace. They provide more information to help us understand the mysterious gamma-ray burst (and neutron-star astrophysics in general). and they demonstrate how important and complementary multi-wavelength observations with space- and ground-based telescopes are in understanding astrophysical phenomena.”
And with both the new GRBs and GRB 211106A, there is still a lot of work to be done at many wavelengths, which may uncover additional surprises about these bursts. “The study of short-duration GRBs requires the rapid coordination of telescopes operating at all wavelengths around the world and in space,” said Edo Berger, professor of astronomy at Harvard University.
“In the case of GRB 211106A, we used some of the most powerful telescopes available—ALMA, the National Science Foundation’s Carl G. Jansky Very Large Array (VLA), NASA’s Chandra X-ray Observatory, and the Hubble Space Telescope. Next-generation VLAs such as the powered James Webb Space Telescope (JWST), and future 20-40 meter optical and radio telescopes (NGVLAs) will be able to produce a more complete picture of these cataclysmic events and study them at unprecedented distances. “
Lasker said, “With JWST, we can now take a spectrum of the host galaxy and easily know the distance, and in the future, we can also use JWST to capture infrared afterglows and study their chemical composition.” With ngVLA, we will be able to study in unprecedented detail the geometric structure of afterglows and the star-forming fuels found in their host environments. I look forward to these upcoming discoveries in my field.”
Tanmay Laskar et al, The first short GRB millimeter afterglow: the wide-angled jet of the extremely energized SGRB 211106A. arXiv:2205.03419v2 [astro-ph.HE], arxiv.org/abs/2205.03419
National Radio Astronomy Observatory
Citation: Explosive neutron star merger captured for the first time in millimeter light (2022, Aug. 3), Aug. 4, 2022 from https://phys.org/news/2022-08-explosive-neutron-star-merger-captured.html taken.
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