# Multi-wavelength study of Mrk 421 TeV flare observed with \\emph{TACTIC} telescope in February 2010

Source: [Multi-wavelength study of Mrk 421 TeV flare observed with \\emph{TACTIC} telescope in February 2010](<https://www.sota2.com/research/paper/68fa31601e209131ce87e1be>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-24T18:48:58.806Z

Authors: K.K. Singh, K.K. Yadav, P. Chandra, S. Sahayanathan, N. Bhatt, R.C. Rannot, A.K. Tickoo, R. Koul

Published: 2014-07-09T05:28:47.000Z

## Abstract

We present results from multi-wavelength study of intense flaring activity from a high frequency peaked BL Lac object Mrk 421. The source was observed in its flaring state on February 16, 2010 with the $TACTIC$ at energies above 1.5 TeV. Near simultaneous multi-wavelength data were obtained from high energy (MeV-GeV) $\\gamma$--ray observations with \\emph{Fermi}--LAT, X--ray observations by the \\emph{Swift} and \\emph{MAXI} satellites, optical V-band observation by SPOL at \\emph{Steward Observatory} and radio 15 GHz observation at OVRO 40 meter-telescope. We have performed a detailed spectral and temporal analysis of $TACTIC$, \\emph{Fermi}--LAT and \\emph{Swift}--XRT observations of Mrk 421 during February 10--23, 2010 (MJD 55237-55250). The flaring activity of the source is studied by investigating the properties of daily light curves from radio to $TeV$ energy range and we present the correlation and variability analysis in each energy band. The $TeV$ flare detected by $TACTIC$ on February 16, 2010 is well correlated with the activity in lower energy bands. The differential energy spectrum of the source, in the energy range 1.5-11 TeV, as measured by $TACTIC$ on this night is described by a power law ($dN/dE \\propto E^{-\\Gamma}$) with spectral index $\\Gamma = 2.6\\pm0.3$. After accounting for absorption of $TeV$ photons by low energy extragalactic background light photons via pair production, the intrinsic $TeV$ spectrum reveals a power law index of $2.3\\pm0.3$. Finally the broad band spectral energy distribution of the source in flaring state is reproduced using a simple emission model involving synchrotron and synchrotron self Compton processes. The obtained parameters are then used to understand the energetics of the source during the flaring episode.

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/1407.2359>)

[PDF](<https://arxiv.org/pdf/1407.2359.pdf>)