The Corpses of Dead Stars Power Intense Gamma Rays

Our Milky Way galaxy contains the sizzling remains of massive stars that have exploded as supernovas. Now, scientists have taken a closer look at what causes supernovas to glow with high-energy gamma rays, investigating what powers these energetic stellar remains.

In order to learn a bit more about supernovas, the researchers turned to NASA's Nuclear Spectroscopic Telescope Array (NuSTAR). In this case, they found that a particular site of powerful gamma rays was being powered by a spinning, dead star called a pulsar. Pulsars are just one of several types of stellar remnants that can be left over when stars explode.

"The energy from this corpse of a star is enough to power the gamma-ray luminosity we are seeing," said Eric Gotthelf, one of the researchers, in a news release.

Over the past few years, researchers have identified more than 80 incredibly powerful sites of gamma rays, called high-energy gamma-ray sources, in our galaxy. While most of these have been associated with supernova explosions, for some of them, the primary source of gamma rays remains unknown.

In this case, the gamma-ray source is one of the most luminous discovered so far. The pulsar produces high-energy rays with its strong magnetic fields, which generate powerful electric fields that accelerate charged particles near the surface to incredible speeds. These particles then interact with the magnetic fields to produce the powerful beams of high-energy gamma rays.

"The discovery of a pulsar engine powering HESS J1640-465 allows astronomers to test models for the underlying physics that result in the extraordinary energies generated by these rare gamma-ray sources," said Gotthelf.

The findings reveal a bit more about the sources for gamma-rays in our galaxy. Currently, the researchers are continuing to hunt for more pulsars with NuSTAR in the hopes of learning a bit more about supernovas.

The findings are published in The Astrophysical Journal.