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Wednesday, January 20, 2021
12:00 PM - 1:00 PM
Online Event

Astronomy Colloquium

Mergers, magnetars and multi-messengers
Stephen Smartt, Professor, Queens University Belfast,

Wide-field optical sky surveys are discovering a remarkable diversity in how stars merge, collapse and explode.  A number of unusual and fast declining transients have been found, but their true volumetric rate appears low.  The powering mechanism for many of these requires a source beyond radioactivity, plausibly a magnetic, rapidly spinning neutron star. In addition, the discovery of an electromagnetic counterpart to a pair of merging neutron stars showed that gravitational wave sources produce transients that emit photons from gamma rays to the radio. Spectral analysis provides a method to determine the composition, ejecta velocity and kinetic energy of the transients, which helps constrain their nature. I will highlight our recent searches for degenerate mergers and fast transients with ATLAS and Pan-STARRS. I will also show how spectroscopic analysis can uncover the composition of these unusual objects. 

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