gamma rays tagged posts

A team of researchers, including UvA physicists and astronomers, has studied gamma rays caused by the Sagittarius Dwarf, a small neighbouring galaxy of our Milky Way. They showed that all the observed gamma radiation can be explained by millisecond pulsars, and can therefore not be interpreted as a smoking gun signature for the presence of dark matter. The results were published in Nature Astronomy this week.

The center of our galaxy is blowing a pair of colossal bubbles ...

Unprecedented observations of a nova outburst in 2018 by a trio of satellites, including two NASA missions, have captured the first direct evidence that most of the explosion’s visible light arose from shock waves — abrupt changes of pressure and temperature formed in the explosion debris.

A nova is a sudden, short-lived brightening of an otherwise inconspicuous star...

This artist’s conception shows a blazar – the core of an active galaxy powered by a supermassive black hole. Scientists using the VERITAS array have detected gamma rays from the blazar TXS 0506+056, which is also thought to be a source of neutrinos. Credit: M. Weiss/CfA

The VERITAS array has confirmed the detection of gamma rays from the vicinity of a supermassive black hole. While these detections are relatively common for VERITAS, this black hole is potentially the first known astrophysical source of high-energy cosmic neutrinos, a type of ghostly subatomic particle.

On September 22, 2017 the IceCube Neutrino Observatory, a cubic-kilometer neutrino telescope located at the South Pole, detected a high-energy neutrino of potential astrophysical origin...

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...