Magnetar Giant Flares: A New Site of R-Process Nucleosynthesis

Pacific
Speaker(s) Brian Metzger (Columbia)
Description

Please contact erule@berkeley.edu for zoom links.

Although much progress has been made in recent years, the astrophysical origin(s) of the rapid neutron capture (r-process) remain elusive.  Thanks to observations of several kilonovae (one being associated with a gravitational wave source), neutron star mergers are now confirmed sites of the r-process; however, other sources may contribute, particularly at low metallicity. I will discuss a new r-process source that occurs from the ejection of neutron star crust material following a magnetar giant flare, such as that which occurred from SGR 1806-20 in December 2004. Radioactive decay of these ejecta gives rise to an extremely brief (~minutes long) optical/UV transient akin to a scaled-down kilonova, which may be detectable with rapidly slewing UV space satellites such as ULTRASAT.  Additional motivation for sizable baryonic ejection from magnetar giant flares comes from their observed radio afterglows and the known magneto-ionic environments of some fast radio bursts (speculated to be powered by exceptionally active magnetars).