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Friday, March 18, 2016
2:00 PM - 3:00 PM
Cahill 370

TAPIR Seminar

The link between fluid instabilities in a core-collapse supernova and asymmetric accretion flows in a collapsing progenitor
Kazuya Takahashi, JSPS Fellow, High-Energy Astrophysics Group, Waseda University,

The explosion mechanism of core-collapse supernova has been debated for many decades. The main topic is how the stalled shock wave in an iron core revives and goes through the core.  In the most promising scenario, neutrinos that diffuse out of a proto-neutron star heat the shocked matter and, as a result, push the stagnant shock wave. This neutrino-heating mechanism is known to be insufficient in spherically symmetric systems, however, where the stalled shock fails to revive.  Hence, multi-dimensional fluid instabilities such as convections and standing accretion shock instabilities are thought to play an important role to help the shock revival by enhancing the efficiency of the neutrino heating.

These instabilities are induced even in a collapse of spherically symmetric progenitors. However, researchers have revealed that core-collapse progenitors are strongly spherically asymmetric because of violent convections that develop in Si/O layers due to nuclear burnings (e.g. Arnett & Meakin 2011). Furthermore, some authors recently performed numerical simulations of the collapse of such non-spherically symmetric progenitors and found that such asymmetric structures lead a successful shock revival even if the shock fails to revive in spherically symmetric case (e.g. Couch & Ott 2013, 2014, Muller & Janke 2014).

In the above context, we performed a linear analysis to investigate the link between multi-dimensional fluid instabilities and the asymmetric accreting matter.  In this talk, I review our analysis and how asymmetric inflows affect the shock dynamics.

 

For more information, please contact JoAnn Boyd by phone at 4280 or by email at joann@caltech.edu.