Shock wave dynamics and breakout in stellar explosions

Tamar Faran (HUJI)
Friday, September 17, 2021 - 11:00am to 12:00pm

Shock waves are ubiquitous in high-energy astrophysics. The first electromagnetic signal observed in different types of stellar explosions, such as supernovae and gamma ray bursts, is released upon emergence of a shock wave from an opaque stellar envelope, enshrouding a central source. The breakout is followed by expansion of the envelope and the release of energy that was deposited there by the shock wave. The escaping radiation shortly after breakout carries direct information on the properties of the progenitors, their surroundings and the explosion, which can be uncovered by confronting observations with analytic models.

In this talk I will first present our model for the early phase radiation following a Newtonian shock breakout in core-collapse supernovae. Through a self similar description of the radiation, we deduce a faster evolving and significantly lower radiation temperature than predicted by previous models. Moving on to the relativistic regime, I will discuss a hydrodynamic solution for the interiors of a spherical ultra-relativistic blast wave. I will end with relativistic shock breakout, where the creation of electron-positron pairs play an important role in regulating the photon temperature. I will highlight applications of this work to low luminosity gamma ray bursts and gamma ray emission in neutron star mergers.

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