Скачать или смотреть New detector finds gamma rays from surprising cosmic sources

(21 May 2021) FOR CLEAN VERSION SEE STORY NUMBER: 4327017

On a windswept Tibetan plateau, a new $175 million observatory in southwestern China has already discovered something that is tantalizing astronomers even before the observatory is technically complete.
Scientists detected bursts of gamma rays from outer space that may someday help explain how matter is created and distributed across the universe.
Astrophysicist Cao Zhen opens a steel hatch and climbs down a ladder into inky darkness. His flashlight picks out a boat floating on a pool of purified water above thousands of glittering orbs the size of beachballs.
He's inside the Large High Altitude Air Shower Observatory, the biggest device of its kind, that has detected a dozen sources of ultra high-energy gamma rays, according to a study in the journal Nature, from what Cao calls "many hot spots," in our Milky Way galaxy.
Gamma rays with such high energy have never been detected before, and the findings suggest these rays can come not just from dying stars, but are also generated inside massive young stars.
Cao's team traced 530 high-energy gamma rays to 12 sources including a massive cluster of young stars called the Cygnus Cocoon and the interstellar cloud called the Crab Nebula.
Gamma rays are a type of extreme radiation generated by the hottest and brightest explosions in the universe, like when a large star implodes. Those implosions also create the matter that make up planets — and everything that lives on them, including us.
Of all the electromagnetic waves in the universe, gamma rays have the smallest wavelengths and the most energy. They can release more energy in 10 seconds than our sun in 10 billion years.
The pool of purified water at LHAASO that Cao paddled across measures the subatomic shrapnel — the "air shower" in the observatory's name — created when gamma rays and high energy particles called cosmic rays crash into the Earth's atmosphere.
The shrapnel includes mysterious particles called muons that can be seen as faint blue flashes known as Cherenkov radiation in the observatory's dark water. The array of 3,120 beachball-sized globes contain tiny sensors that measure the radiation.
Cao, dressed in blue scrubs to keep the water clean, said these gamma rays can be traced back to find something new.
LHAASO is one of dozens of devices on Earth and in orbit — suspended in ice tunnels in Antarctica or inside toaster-sized satellites — trying to understand how matter such as carbon, oxygen and iron came to be.
Located near the 4,400-meter-tall (14,500-foot-tall) Haizi Mountain, it houses separate instruments that can study different phenomena, including cosmic rays, high energy subatomic particles that scientists believe come from the same sources as gamma rays.
It's not yet complete, however. Cao said that by the end of June the instruments will be in place, including 5,195 electromagnetic detectors, 1,188 muon detectors, and 18 Cherenkov telescopes each the size of a shipping container that will study air showers in the sky.

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