Unusual gamma-ray burst reveals previously undetected hybrid neutron-star merger event

[fred8615]

The standard view of gamma-ray bursts as a signature for different types of dying stars might need a rewrite. Recent astronomical observations, supported by theoretical modeling, reveal a new observational fingerprint of neutron-star mergers, which may shed light on the production of heavy elements throughout the universe.

"Astronomers have long believed that gamma-ray bursts fell into two categories: long-duration bursts from imploding stars and short-duration bursts from merging compact stellar objects," said Chris Fryer, an astrophysicist and Laboratory Fellow at Los Alamos National Laboratory. Fryer is coauthor and leader of the modeling team on a paper about the phenomenon published in Nature. "But in a recently observed event, we've found a kilonova along with a long-duration gamma-ray burst, and that has thrown a wrench into this simple picture."

Hypernovae/supernovae are the visible-light, transient objects produced in these explosions from imploding objects, while kilonovae are visible-light transients produced by merging compact objects where at least one is a neutron star. Gamma-ray bursts can accompany both types of transients. Supernovae are produced when a massive star explodes; only a small subset of supernovae arise from the explosion mechanism that produces gamma-ray bursts.

Read more: https://www.spacedaily.com/reports/Unus ... t_999.html