Pancharatnam Lecture

Seeing the High Energy Universe

Speaker: Prof. Subir Sarkar (University of Oxford)

Date and time


The past decade has witnessed the opening up of a new window on to the Universe with the coming of age of high-energy neutrino astronomy. The IceCube experiment at the South Pole discovered a diffuse flux of astrophysical neutrinos at TeV-PeV energies, and also identified the first candidate source for this flux: a flaring blazar 5.7 billion light-years away. This was a breakthrough in real-time multi-messenger astronomy and has thrown up significant challenges to astrophysical models of such active galactic nuclei. Intriguingly no neutrinos have been detected from gamma-ray bursts, nor were any seen from the binary neutron star merger detected in gravitational waves. Resolving the high energy neutrino sky and furthering our understanding of such extreme environments in the Universe will require IceCube-Gen2, which will have 8 times the instrumented in-ice volume, in addition to a surface array including radio detectors to extend the energy range by 3–4 orders of magnitude. Such a facility also has immense potential to probe new physics beyond the Standard Model with ultra-high energy cosmic neutrinos. Opportunities for Indian participation in this exciting endeavour will be discussed.


Subir Sarkar received his PhD (1982) from the Tata Institute of Fundamental Research, Bombay, where he was a staff member from 1979-84. Since 1990 he has been at the University of Oxford, where he was appointed Professor in 2006 and Head of the Particle Theory Group 2011-19. His interests lie at the interface of fundamental physics with astrophysics and cosmology - dark matter, dark energy, inflation & the cosmic microwave background, neutrinos, primordial nucleosynthesis, etc. He also works on high energy cosmic rays, neutrinos & gamma-rays and belongs to the IceCube Neutrino Observatory and the Cherenkov Telescope Array collaborations. Earlier, he worked on the Pierre Auger Observatory and the CERN BEBC Beam Dump experiment. In 2017 he was awarded the IUPAP-TIFR Homi Bhabha prize for “distinguished contributions in the field of high energy cosmic ray physics and astroparticle physics over an extended academic career.