State of the Universe

Cosmic rays from star clusters

by Prof. Biman Nath (RRI, Bengaluru)

Wednesday, March 20, 2024 from to (Asia/Kolkata)
at AG80 and Zoom : Link to join the meeting: https://us02web.zoom.us/j/82512956967?pwd=angyQ0ZDdHZUdzFUbjkybmxsWFNFUT09 Meeting ID: 825 1295 6967 Passcode: 384194
Description
The conventional wisdom is that Galactic cosmic rays are accelerated in supernova shocks of massive stars. However, before they explode, massive stars also produce strong stellar winds. They also appear in clusters, and the collective effect of stellar winds over time can be quite strong, and comparable to the blast wave energy of a supernova explosion. I will argue that stellar winds from massive star clusters offer an alternative site for cosmic ray acceleration, producing up to a quarter of all Galactic cosmic rays, especially in the range of 10^7-10^9 GeV, and can also explain a number of phenomena that cannot be accommodated within the supernova paradigm.