Sarira Sahu

Hadronic-origin orphan TeV flare from 1ES 1959+650

The 1ES 1959+650 is a high-peaked BL Lacertae object. On 4th of June, 2002, it exhibited a strong TeV flare without any low energy counterpart, providing for the first time an example of an orphan flare from a blazar. Observation of this orphan flare is in striking disagreement with the predictions of the leptonic models thus challenging the conventional synchrotron self-Compton (SSC) interpretation of the TeV emission. Here we propose that, the low energy tail of the SSC photons in the blazar jet serve as the target for the Fermi-accelerated high energy protons of energy . 100 TeV, within the jet to produce the TeV photons through the decay of neutral pions from the delta resonance. Our model explains very nicely the observed TeV flux from this orphan flare and we also estimate the high energy neutrino flux from this flaring event.

Hadronic-Origin TeV -Rays and Ultra-High Energy Cosmic Rays from Centaurus A

Centaurus A (Cen A) is the nearest radio-loud AGN and is detected from radio to very high energy gamma-rays. Its nuclear spectral energy distribution (SED) shows a double-peak feature, which is well explained by the leptonic synchrotron + synchrotron self-Compton model. This model however cannot account for the observed high energy photons in the TeV range, which display a distinct component. Here we show that ~ TeV photons can be well interpreted as the neutral pion decay products from p-gamma interactions of Fermi accelerated high energy protons in the jet with the seed photons around the second SED peak at ~170 keV. Extrapolating the inferred proton spectrum to high energies, we find that this same model is consistent with the detection of 2 ultra-high-energy cosmic ray events detected by Pierre Auger Observatory from the direction of Cen A. We also estimate the GeV neutrino flux from the same process, and find that it is too faint to be detected by current high-energy neutrino detectors.

Effect of a random magnetic field on active-sterile neutrino conversion in the supernova core

The active-sterile neutrino conversion is studied for neutrino propagating in the axial potential generated by magnetised electron plasma in the supernova medium. We consider the effect of random magnetic field

NUCLEON PROPERTIES IN CHIRAL COLOR DIELECTRIC MODEL

B_{rms}

HIGHER ORDER CORRECTION TO THE NEUTRINO SELF-ENERGY IN A MEDIUM AND ITS ASTROPHYSICAL APPLICATIONS

on the average neutrino conversion probability. We obtained the constraint on

COSMIC RAYS PROPAGATION IN A PSEUDO-SCALAR MEDIUM

Delta m^2

NEUTRINO PROPAGATION IN AGN ENVIRONMENT

and

Beyond the standard model: working group report

sin^2 2theta

Neutrino propagation in a random magnetic field

for different strength of the random magnetic fields, by considering the positive definiteness of the average neutrino conversion probability inside the supernova core. Our calculation shows that,

Cherenkov radiation of longitudinal photons by neutrinos

B_{rms}le 0.63times 10^{14}