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Dead stars in Milky Way’s companion galaxy cause gamma-ray cocoon | Space

The Fermi bubbles are massive structures extending from the Milky Way, reaching 50,000 light-years in length.

Mysterious ultrabright gamma-ray emissions in the giant bubbles blown out by our galaxy may finally have an explanation.

Researchers used data from the Gaia and Fermi space telescopes to search through the Fermi bubbles, a pair of colossal hourglass-shaped bubbles that extend from the poles of the Milky Way and span 50,000 light-years, to trace the source of the very bright gamma-ray emission spots.

They discovered that one of the brightest of these spots, dubbed the “Fermi cocoon,” located in the southern bubble, was caused by emissions from rapidly spinning dead stars called pulsars in the Milky Way’s satellite galaxy Sagittarius. The finding could shed light on how these collapsed dead stars act as cosmic particle accelerators, blasting out high-energy particles that go on to cause gamma-ray emissions.  …