University of Maryland
Atlantic Building, Room 2400
4:30 PM Monday, October 3, 2016
Coffee, Tea & Snacks 4:15-4:30 PM

Peter Biermann
MPIfR, Bonn; KIT, Karlsruhe; Univ. of Alabama, Tuscaloosa; Univ. of Bonn
Massive star explosions, cosmic rays and gravitational waves

Massive stars explode via a mechanism which we do not know. All of them are in binary star systems. A fraction of them blow up as Gamma Ray Bursts. Massive stars, depending on their heavy element abundance, commonly produce stellar black holes. When two such black holes are produced they finally merge in a gigantic burst of gravitational waves, now observed. All of these stars have powerful magnetic winds, that throw out most of their zero-age mass before the explosion. When they blow up the shock races through this wind and the surrounding shell to produce cosmic ray particles: The supernova shock speed through the wind and the magnetic field in the wind are observed, both for blue super-giant star explosions as well as for red super-giant star explosions: numbers for both kinds of stars are essentially the same. The implied characteristic particle energies are EBohm = 1015.3 ± 0.3 Z eV; and EJokipii = 1017.3 ± 0.2 Z eV, just what the data require for knee and ankle. Thus, by studying the cosmic ray particles, their abundances at knee energies, and their spectra, we can learn about what drives these stars to produce the most powerful outbursts yet known in the universe.

Sponsored by: Department of Physics and the Institute for Physical Science and Technology, University of Maryland. For information call Catha Stewart at (301) 405-4811 or go to the UMD Space Physics group seminar web site.

There is free parking after 4:00 PM in lot B (the big parking garage across the street from the ATL building). There are a limited number of spaces in lot Q next to the new ATL wing with free parking after 4PM even when there is a basketball game on campus.