Very High Energy Cosmic Ray and Neutrino Events from Centaurus A
Abstract
Centaurus A is the nearest radio-loud AGN and is detected from radioto very high energy gamma-rays. Its nuclear spectral energydistribution shows two peaks, one in the far-infrared band and anotherat about 170 keV. Although, the flux from this nuclear region iswell explained by leptonic models, it fails to account for highenergy tail region above few GeV. We show that, within the jet, thecollision of Fermi accelerated high energy protons with the IC photonsaround the second peak region can produce multi-GeV to TeV gamma-raysand GeV neutrinos through delta-resonance which can explainsimultaneously, the observed GeV-TeV tail in the photon flux and theobserved cosmic ray events by Pierre Auger Observatory. We also estimatethe GeV neutrino flux from it.
12/07/2011 at 4:00 pm
Dr. Anurag Sahay
HEP/CMP Seminar
Lecture Hall Block A, Institute of Physics
Document Date:
Thermodynamic geometry, phase transitions and the Widom line`
Thermodynamic geometry, phase transitions and the Widom line`
Abstract
In this talk we propose a novel method to characterize first order phasetransitions using the scalar curvature of the equilibrium thermodynamicstate space. Furthermore, our construction naturally characterizes theWidom line through the maxima of the correlation length. As anillustration, we use it in conjunction with the mean field Van der Waalsequation of state to predict the coexistence curve and the Widom line.Where closely applicable, it provides good agreement with experimentaldata. It generalizes to diverse systems like anti de Sitter black holes,which also exhibit first-order phase transitions.
