| Name: CHANDAN KUMAR DAS |
| Affiliation: Indian Institute of Technology Indore |
| Conference ID: ASI2026_794 |
| Title: On the Origin of Ultra-High-Energy Neutrinos in Relativistic Blazar Jets |
| Abstract Type: Poster |
| Abstract Category: High Energy Phenomena, Fundamental Physics and Astronomy |
| Author(s) and Co-Author(s) with Affiliation: Chandan Kumar Das(Indian Institute of Technology Indore, Indore - 453552, India), Sushmita Agarwal(Tata Institute of Fundamental Research, Mumbai - 400005, India), Amit Shukla(Indian Institute of Technology Indore, Indore - 453552, India), Bhargav Vaidya(Indian Institute of Technology Indore, Indore - 453552, India) |
| Abstract: The detection of very high-energy astrophysical neutrinos provides crucial insight into the most powerful particle accelerators in the Universe. In particular, the ~2 PeV IceCube neutrino event IC35 and the recent KM3NeT event KM3-230213A, with an inferred energy of 220 PeV, place strong constraints on the physical conditions required for neutrino production. Relativistic jets from active galactic nuclei (AGNs), especially blazars, are among the leading candidate sources; however, the mechanisms that can accelerate particles to such extreme energies remain uncertain. In this work, we present a unified theoretical study of high-energy neutrino production in blazar jets. We constrain the relevant physical parameters of the jet environment by systematically comparing particle acceleration timescales with cooling timescales associated with the dominant energy-loss processes. In particular, we focus on photo-pion interactions, which are expected to be the primary channel for producing high-energy neutrinos in astrophysical sources. This timescale-based approach enables us to identify the conditions under which protons can be accelerated efficiently to PeV-EeV energies without suffering significant energy losses, thereby allowing for the observability of this ultra-high-energy neutrino event by KM3NeT. We further apply this framework to a comparative study of two major flaring episodes of the blazar PKS B1424-418. The first flare (2012–2013) is spatially and temporally coincident with the event IC35, whereas a second, brighter gamma-ray flare in 2021 shows no clear neutrino association. By comparing these two flares, we examine how differences in jet parameters influence neutrino production efficiency and assess the conditions required for observable neutrino emission. |
