Brightest Cosmic Explosion Reveals Possible Clues to Dark Matter

Hen Sunday, October 9, Judith Racusin He was 35,000 feet in the air on his way to a high-energy astrophysics conference when the biggest cosmic explosion in history happened. “I landed, looked at my phone and got dozens of messages,” said Rakusin, an astrophysicist at NASA’s Goddard Space Flight Center in Maryland. “It was truly exceptional.”

The explosion was a long gamma-ray burst, a cosmic event in which a massive dying star releases powerful jets of energy as it collapses into a black hole or neutron star. This particular burst was so bright that it partially oversaturated the Fermi Gamma-ray Space Telescope, an orbiting NASA telescope designed to observe such events. “There were so many photons per second that they couldn’t catch up,” they said Andrew LevanAstrophysicist at Radboud University in the Netherlands. It even seems that the explosion of the Earth’s ionosphere, which is the upper layer of the Earth’s atmosphere swells in size a few hours. “It’s pretty incredible that you can change the Earth’s ionosphere from an object halfway across the universe,” he said. Doug WelchAstronomer at McMaster University in Canada.

Astronomers called it the “brightest of all time” and pressed it for information about gamma-ray bursts and more about the cosmos. “Even 10 years from now, there will be new insights from this data set,” they said Eric Burns, an astrophysicist at Louisiana State University. “It still hasn’t hit me that this is actually happening.”

Preliminary analysis suggests that there are two reasons why BOAT is so brilliant. First, it occurred about 2.4 billion light-years from Earth, close enough to gamma-ray bursts (although well outside our galaxy). Most likely, the powerful jet of the BOAT was directed towards us. Two factors combined to make this a once-in-a-hundred-years event.

Perhaps the most impressive observation occurred in China. There, the Large High Altitude Air Shower Observatory (LHAASO) in Sichuan Province tracks high-energy particles from space. In the history of gamma-ray burst astronomy, researchers have seen only a few hundred high-energy photons come from these objects. LHASO I saw 5000 from this one event. “The gamma-ray burst basically exploded directly in the sky above them,” they said Sylvia ZhuAstrophysicist at the German Electron Synchrotron (DESY) in Hamburg.

Among those detections was a suspiciously high-energy photon at 18 teraelectron volts (TeV) — four times higher than anything seen before the gamma-ray burst and more energetic than the highest energy the Large Hadron Collider can achieve. Such a high-energy photon would have to be lost on its way to Earth as a result of interactions with the background light of the universe.

But how did it get here? one opportunity that is, after the gamma-ray burst, the high-energy photon turned into an axion-like particle. stocks are hypothesized light particles could explain dark matter; particles like axion are thought to be slightly heavier. Could be high energy photons becomes such particles strong magnetic fields, such as those around an exploding star. A particle like an axion would move unimpeded through space. When it reaches our galaxy, its magnetic fields will turn it back into a photon, which will then make its way to Earth.

During the week after the initial detection, many groups of astrophysicists proposed this mechanism In articles uploaded to the scientific preprint site arxiv.org. “It would be a very incredible discovery,” said Giorgio Galanti, an astrophysicist at the National Institute of Astrophysics (INAF) in Italy. the first of these documents.

Other researchers wonder if the detection of LHAASO could be a case of mistaken identity. Perhaps the high-energy photon came from somewhere else and the exact timing of its arrival was just a coincidence. “I’m very skeptical,” they said Milena Crnogorcevic, an astrophysicist at the University of Maryland. “At this point, I’m leaning towards it being a background event.” (To complicate matters further, a Russian observatory informed a shock from a higher-energy 251 TeV photon from the explosion. “The jury’s still out on that,” said Rakusin, deputy project scientist at the Fermi telescope. “I’m a little skeptical.”)

So far, the LHAASO team has not released detailed results of their observations. Burns, who is coordinating the global collaboration to study BOAT, hopes. “I’m very interested to see what they have,” he said. But he understands why some degree of caution might be warranted. “If I was sitting on data that had a few percent chance of identifying evidence of dark matter, I would be extraordinarily cautious at this point,” Burns said. If the photon can be associated with BOAT, “it will likely be evidence of new physics and potentially dark matter,” Crnogorčević said. The LHAASO team did not respond to a request for comment.

Even without data from LHAASO, the amount of visible light from the event could allow scientists to answer some of the biggest questions about gamma-ray bursts, including key puzzles about the jet itself. “How is a plane launched? What happens in a jet that spreads into space?” he said Tyler Parsons, an astrophysicist at Goddard. “These are really big questions.”

Other astrophysicists hope to use BOAT to learn just why some stars produce gamma-ray bursts on their way to supernova. “This is one of the great mysteries,” they said Yvette Cendez, an astronomer at the Harvard-Smithsonian Center for Astrophysics. “It must be a very big star. A galaxy like ours will produce a gamma-ray burst perhaps once every million years. Why such a rare population of gamma-ray bursts?”

Whether gamma-ray bursts lead to a black hole or a neutron star in the core of a collapsed star is also an open question. A preliminary analysis of BOAT suggests that the former occurred in this study. “There’s so much energy in the jet that it should basically be a black hole,” Burns said.

What is certain is that this is a cosmic event that will not be captured for many lifetimes. “By the time we get a chance to do this again, we’ll all be long dead,” Burns said.

Lead image: The rings around the explosion, visible in color data from NASA’s Swift observatory, were formed when X-rays scattered hidden dust in our Milky Way galaxy. Credit: NASA Swift Observatory; Processing: Jon Miller.

This was the article originally published where How many abstractions blog.