TAPIR Seminar

I will describe recent work on the observable signatures of compact object birth in two situations.  The first scenario is the formation of a rapidly rotating, strongly magnetized neutron star (a 'millisecond magnetar') following the core collapse of a massive star.  The birth of such objects has been suggested to explain a recently discovered class of 'super-luminous' supernovae.  I will present a model for the evolution of young millisecond pulsar wind nebulae that describes how their non-thermal radiation 'thermalizes' with the surrounding opaque ejecta, producing anomalously bright optical emission.  Nebular X-rays may be sufficiently luminous to re-ionize--and hence to escape from--the ejecta within months after the explosion, providing a potential test of the magnetar model.

The second source I will describe is the coalescence of binary neutron stars, the primary source for the direct detection of gravitational waves by Advanced LIGO.  A generic feature of such mergers and their aftermath is the ejection of neutron-rich material, which synthesizes heavy radioactive elements as it expands away from the merger site.  Thermal emission produced by the decay of these nuclei powers a dim optical transient known as a 'kilonova.'  I will show how the colors and duration of the kilonova may encode information about the post-merger evolution (in particular, the time of black hole formation) not otherwise available in the detected gravitational waveform.