High energy astrophysics during the multi-messenger era

	IceCube, the largest neutrino telescope has detected 82 high energy starting events (HESE) in the energy range of 20 TeV- 2 PeV. The origin of these cosmic neutrinos is one of the outstanding puzzles in recent years. An astrophysical origin is possible if they show ignificant angular correlation with their possible counterparts in high energy gamma rays and extreme energy cosmic rays. We have studied the angular correlation of the HESE events with the high energy gamma ray sources detected by Fermi LAT and the extreme energy cosmic ray events detected by extensive air shower arrays to find out whether there is any significant correlation. I will discuss our results and future prospects in my talk. I will also discuss about high energy neutrino production in one of the most energetic astrophysical object, Gamma Ray Bursts (GRBs). Adding implication of GRB classification as a outcome of GW170817.