High Energy Physics Seminars

Cosmic-ray origin and propagation in the Galaxy: Implication from new measurements

by Dr. Satyendra Thoudam (Department of Physics & Electrical Engineering, Linnaeus University, Sweden)

Monday, January 28, 2019 from to (Asia/Kolkata)
at TIFR, Mumbai ( AG-66 )
Recent high-precision measurements have revealed several new properties of cosmic rays that challenge the standard model of the origin and propagation of cosmic rays in the Galaxy. New key properties include spectral hardening of cosmic-ray nuclei at about 200 GeV/nucleon, break in the electron spectrum at about 1 TeV, rise in the positron fraction at about 10 GeV, and a dominant contribution of light nuclei at about 1017 eV. I will discuss how these new measurements indicate the importance of various processes, which are commonly neglected in cosmic-ray propagation models. I will then present a model we have proposed to explain the energy spectrum and composition of cosmic rays over the entire energy range up to about 5x1018  eV, taking into account some of the observed new key features. I will also talk about the origin of gamma rays from the Fermi Bubbles, and its possible connection with the distribution of cosmic rays in the Galaxy.