Positrons and 511 keV Radiation as Tracers of Recent Binary Neutron Star Mergers
George M Fuller1, Alexander Kusenko2,3, David Radice4,5
1Department of Physics, University of California, San Diego La Jolla, California 92093-0354, USA.
Abstract:
Neutron-rich material ejected from neutron star-neutron star (NS-NS) and neutron star-black-hole (NS-BH) binary mergers is heated by nuclear processes to temperatures of a few hundred keV, resulting in a population of electron-positron pairs. Some of the positrons escape from the outer layers of the ejecta. We show that the population of low-energy positrons produced by NS-NS and NS-BH mergers in the Milky Way can account for the observed 511-keV line from the Galactic center (GC). Moreover, we suggest how positrons and the associated 511-keV emission can be used as tracers of recent mergers. Recent discovery of 511-keV emission from the ultrafaint dwarf galaxy Reticulum II, consistent with a rare NS-NS merger event, provides a smoking-gun signature of our proposal.
Related Concept Videos
Types of Radioactivity
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
Biological Effects of Radiation
Binary Fission
Binary Fission
Radiation: Applications
The average...
Positron Emission Tomography
One of the main requirements of a PET scan is a positron-emitting radioisotope, which is produced in a cyclotron and then attached to a substance used by the part of the body...


