Tracking Zombie Stars With Gamma Rays

The sizzling remains of countless dead stars in our Universe still pulse with some radioactive activity, namely high-energy pulses of gamma rays. Now astronomers and researchers believe they are one step closer to understanding why this stellar phenomenon occurs.

Researchers recently used NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) to measure and confirm the source of a particularly high energy gamma ray emission. They determined it was coming from a pulsar - which is technically a dead star, or "stellar remnant" that is left after a dying star goes supernovae.

It has long been known that pulsars emit huge streams of gamma radiation and radio waves, however researchers believe that with practice, the tracking method most recently used with the NuSTAR can help them better understand how and why these zombie stars emit gamma rays in the first place.

"The energy from this corpse of a star is enough to power the gamma-ray luminosity we are seeing," researcher Eric Gotthelf of Columbia University said in a statement.

He explained that confirming suspected pulsars with NuSTAR can help whittle down pulsar locations, as there are many other sources of gamma radiation in the Universe, many of which we still don't understand.

The results were detailed in The Astrophysical Journal earlier this year.

The gamma-ray source pinpointed in this new study, called HESS J1640-465, is one of the most luminous discovered so far. It was already known to be linked with a supernova remnant, but the source of its power was unclear.

"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-rays sources," added Gotthelf.

With the NuSTAR tracking technique being used to complement other pulsar searches using devices like the Chandra orbital observatory and the XMM-Newton, researchers hope to have a better chance at finding more pulsars, determining new ways to distinguish their emissions from the rest of the Universe.