VHE observation of Mrk 421 with TACTIC during 2012; multiwavelength study

Abstract The nearby ( z = 0.031 ) TeV γ -ray emitter BL Lac object Mrk 421 has been observed with the TACTIC telescope for nearly 118 hours during 01 February to 26 April, 2012 (MJD 55958–56044). Detailed analysis reveals the detection of 529 ± 76 γ -rays with 6.9 σ significance above 850  GeV energy threshold during the period of 15–26 March, 2012 (MJD 56001–56013). Nearly simultaneous multiwavelength observations of the source also indicate a comparatively higher flux state during this period (MJD 56001–56013). In this paper, we present the study of Mrk 421 during this period in very high energy (VHE) domain along with the results from high energy (HE), X-ray, optical and radio observations. We reproduce the spectral energy distribution (SED) of the source during this period using the synchrotron and synchrotron self-Compton (SSC) process. The model parameters of the emission region of the source are found to be consistent with the values reported in the literature.