TeV gamma-ray observations of Markarian 421 using TACTIC during 2009–10

Chandra, P.; Rannot, R. C.; Yadav, K. K.; Tickoo, A. K.; Singh, Krishna Kumar; Chanchalani, K.; Kothari, M.; Agarwal, Nikita; Goyal, A.; Goyal, H. C.; Kotwal, S.; Kumar, Naveen; Marandi, P.; Venugopal, K.; Bhat, C. L.; Bhatt, N.; Bhattacharya, Souradeep; Borwankar, C.; Chouhan, N.; Dhar, V. K.; Kaul, S. R.; Koul, Sukhwinder; Koul, M. K.; Koul, R.; Mitra, Abhas; Sahayanathan, S.; Sharma, M.

doi:10.1088/0954-3899/39/4/045201

Cited by 17 publications

(14 citation statements)

References 62 publications

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“…The VHE observations of the source during this flare have also been reported by various IACT groups like VERITAS [27], HESS [28] and TACTIC [23]. Long term VHE observations of the source during 2009-10 with TACTIC have also been reported [29]. [32] in leptohadronic single zone model.…”

Section: Introductionsupporting

confidence: 68%

Numerical study on the variation of pressure on India Bhabha Atomic Research Center (BARC) and Imperial College plasma focus machines

Singh¹,

Saw²,

Lee

2017

AIP Conference Proceedings

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A time dependent approach to model X-ray and γ-ray light curves of Mrk 421 observed during the flare in Abstract Strong X-ray and γ-ray flares have been detected in February 2010 from the high synchrotron peaked blazar Mrk 421 (z=0.031). With the motivation of understanding the physics involved in this flaring activity, we study the variability of the source in X-ray and γ-ray energy bands during the period February 10-23, 2010(MJD 55237-55250). We use near simultaneous X-ray data collected by MAXI, Swift-XRT and γ-ray data collected by Fermi-LAT and TACTIC along with the optical V-band observations by SPOL at Steward Observatory. We observe that the variation in the one day averaged flux from the source during the flare is characterized by fast rise and slow decay. Besides, the TeV γ-ray flux shows a strong correlation with the X-ray flux, suggesting the former to be an outcome of syn-chrotron self Compton emission process. To model the observed X-ray and γ-ray light curves, we numerically solve the kinetic equation describing the evolution of particle distribution in the emission region. The injection of particle distribution into the emission region, from the putative acceleration region, is assumed to be a time dependent power law. The synchrotron and synchrotron self Compton emission from the evolving particle distribution in the emission region are used to reproduce the X-ray and γ-ray flares successfully. Our study suggests that the flaring activity of Mrk 421 can be an outcome of an efficient acceleration process associated with the increase in underlying non-thermal particle distribution.

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Section: Introductionsupporting

confidence: 68%

Numerical study on the variation of pressure on India Bhabha Atomic Research Center (BARC) and Imperial College plasma focus machines

Singh¹,

Saw²,

Lee

2017

AIP Conference Proceedings

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“…Mrk 421 was detected during the flare, exhibiting different flux states above 250 GeV from 2010 February 13-17 by the HAGAR telescope array located at Hanle, India (Shukla et al 2012). Activity of the source for these days was also reported by the TACTIC telescope (in operation at Mount Abu in Western India) above 1 TeV (Singh et al 2015;Chandra et al 2012). Both HAGAR and TACTIC observed Mrk 421 on 2010 February 16 and reported an enhancement in flux compared to previous days.…”

Section: Very High Energy (Vhe) Gamma-ray Datamentioning

confidence: 85%

Time-dependent spectral modelling of Markarian 421 during a violent outburst in 2010

Banerjee

Joshi

Majumdar

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present the results of extensive modeling of the spectral energy distributions (SEDs) of the closest blazar (z=0.031) Markarian 421 (Mrk 421) during a giant outburst in February 2010. The source underwent rapid flux variations in both X-rays and very high energy (VHE) gamma-rays as it evolved from a low-flux state on 2010 February 13-15 to a high-flux state on 2010 February 17. During this period, the source exhibited significant spectral hardening from X-rays to VHE gamma-rays while exhibiting a "harder when brighter" behavior in these energy bands. We reproduce the broadband SED using a time-dependent multi-zone leptonic jet model with radiation feedback. We find that an injection of the leptonic particle population with a single power-law energy distribution at shock fronts followed by energy losses in an inhomogeneous emission region is suitable for explaining the evolution of Mrk 421 from low-to high-flux state in February 2010. The spectral states are successfully reproduced by a combination of a few key physical parameters, such as the maximum & minimum cutoffs and power-law slope of the electron injection energies, magnetic field strength, and bulk Lorentz factor of the emission region. The simulated light curves and spectral evolution of Mrk 421 during this period imply an almost linear correlation between X-ray flux at 1-10 keV energies and VHE gamma-ray flux above 200 GeV, as has been previously exhibited by this source. Through this study, a general trend that has emerged for the role of physical parameters is that, as the flare evolves from a low-to a high-flux state, higher bulk kinetic energy is injected into the system with a harder particle population and a lower magnetic field strength.

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“…Recent VHE observations of this source are reported by various groups [12,13,14,15,16]. Long term observations of Mrk 421 during 2009-10 with T ACT IC have been reported in [17]. The source was observed in high flaring state during February 2010 in X-ray and γ-ray bands [18,19,20,21].…”

Section: Introductionmentioning

confidence: 98%

Multi-wavelength study of Mrk 421 TeV flare observed with TACTIC telescope in February 2010

Singh

Yadav

Chandra

et al. 2015

Astroparticle Physics

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TeV gamma-ray observations of Markarian 421 using TACTIC during 2009–10

Cited by 17 publications

References 62 publications

Numerical study on the variation of pressure on India Bhabha Atomic Research Center (BARC) and Imperial College plasma focus machines

Numerical study on the variation of pressure on India Bhabha Atomic Research Center (BARC) and Imperial College plasma focus machines

Time-dependent spectral modelling of Markarian 421 during a violent outburst in 2010

Multi-wavelength study of Mrk 421 TeV flare observed with TACTIC telescope in February 2010

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