Multiwavelength study of TeV Blazar Mrk421 during giant flare and observations of TeV AGNs with HAGAR

TL;DR

This study uses the HAGAR telescope to observe TeV blazars, focusing on Mrk421's giant flare, to better understand gamma-ray emission mechanisms and derive physical parameters of these energetic sources.

Contribution

First detailed multiwavelength analysis of Mrk421's 2010 flare using HAGAR, including spectral energy distribution and data analysis methods for TeV blazars.

Findings

Detected flux enhancement during Mrk421 flare, reaching 6-7 Crab units.

Presented spectral energy distribution during the flare.

Discussed data analysis procedures for HAGAR gamma-ray observations.

Abstract

The radiation mechanism of very high energy $\gamma$-ray emission from blazars and crucial parameters like magnetic field, and size of the emitting region are not well understood yet. To understand the above mentioned properties of blazars, we observed five nearby TeV $\gamma$-ray emitting blazars (Mrk421, Mrk501, 1ES2344+514, 1ES1218+304 and 3C454.3) and one radio galaxy (M87) using the High Altitude GAmma Ray (HAGAR) telescope. HAGAR is an array of seven telescopes located at Hanle, India to detect Cherenkov light caused by extensive air showers initiated by $\gamma$-rays. Mrk421 was observed to undergo one of its brightest flaring episodes on 2010 February 17, and detected by various experiments in X-rays and $\gamma$- rays. HAGAR observations of this source during 2010 February 13 - 19, in the energies above 250 GeV show an enhancement in the flux level, with a flux of 6-7 Crab units being detected on 2010 February 17. We present the spectral energy distribution of the source during this flaring episode. In addition to this, the analysis procedure to extract $\gamma$-ray signal from HAGAR data is discussed and preliminary results on all the AGNs are presented.