gamma rays tagged posts

This image illustrates the “multi-messenger” emission from a gigantic reservoir of cosmic rays that are accelerated by powerful jets from a supermassive black hole. Credit: Kanoko Horio

New model connects the origins of very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays with black-hole jets embedded in their environments. One of the biggest mysteries in astroparticle physics has been the origins of ultrahigh-energy cosmic rays, very high-energy neutrinos, and high-energy gamma rays. Now, a new theoretical model reveals that they all could be shot out into space after cosmic rays are accelerated by powerful jets from supermassive black holes.

The model explains the natural origins of all three types of “cosmic messenger” particles simultaneously, and is the...

Sequence showing two white dwarfs spiraling into one another, merging and then exploding as a supernova. As they spiral around each other, they emit gravitational waves causing them to grow ever closer. Credit: GSFC/Dana Berry.

A team of international astrophysicists led by ANU has shown how most of the antimatter in the Milky Way forms. Antimatter is material composed of the antiparticle partners of ordinary matter – when antimatter meets with matter, they quickly annihilate each other to form a burst of energy in the form of gamma-rays. Scientists have known since the early 1970s that the inner parts of the Milky Way galaxy are a strong source of gamma-rays, indicating the existence of antimatter, but there had been no settled view on where the antimatter came from.

ANU researcher Dr R...

Penn State University astronomers have discovered that the mysterious “cosmic whistles” known as fast radio bursts can pack a serious punch, in some cases releasing a billion times more energy in gamma-rays than they do in radio waves and rivaling supernovae in their explosive power. The discovery, the first-ever finding of non-radio emission from any fast radio burst, drastically raises the stakes for models of fast radio bursts and is expected to further energize efforts to chase down long-lived counterparts to FRBs using X-ray, optical, and radio telescopes.

FRBs, were first discovered in 2007, and in the years since radio astronomers have detected a few dozen of these events...