Multiwavelength study of TeV Blazar Mrk421 during giant flare

TL;DR

This study analyzes a major flare of the TeV blazar Mrk421 in February 2010 using multiwavelength data, revealing correlated variability and suggesting a shock in the jet as the flare's cause.

Contribution

First multiwavelength analysis of Mrk421's 2010 flare combining gamma-ray, X-ray, and optical data to understand its physical mechanisms.

Findings

Detected a peak flux of ~7 Crab units during the flare.

Observed correlated variability in X-ray and gamma-ray bands.

Flaring likely caused by a passing shock in the jet.

Abstract

Context: The nearby (z=0.031) TeV blazar Mrk421 was reported to be in a high state of flux activity since November, 2009. Aims: To investigate possible changes in the physical parameters of Mrk421 during its high state of activity using multiwavelength data. Methods: We have observed this source in bright state using High Altitude GAmma Ray (HAGAR) telescope array at energies above 250 GeV during February 13 - 19, 2010. Optical, X-ray and gamma-ray archival data are also used to obtain the SEDs and light curves. Results: Mrk421 was found to undergo one of its brightest flaring episodes on February 17, 2010 by various observations in X-rays and gamma-rays. HAGAR observations during February 13 - 19, 2010 at the energies above 250 GeV show an enhancement in the flux level, with a maximum flux of ~ 7 Crab units being detected on February 17, 2010. We present the spectral energy distributions during this flaring episode and investigate the correlation of the variability in X-ray and gamma-ray bands. Conclusions: Our multiwavelength study suggests that the flare detected during February 16 and 17, 2010 could arise due to a passing shock in the jet.