X-ray Flare in Markarian 421
ATel #7654; Bidzina Kapanadze (Abastumani Astrophysical Observatory at Ilia State University, Tbilisi, Georgia)
on 17 Jun 2015; 17:35 UT
Credential Certification: Bidzina Kapanadze (bidzina_kapanadze@iliauni.edu.ge)
Subjects: X-ray, AGN, Blazar
The nearby TeV-detected high-energy peaked BL Lacertae object Markarian 421 (z=0.031) was targeted four times by the Swift satellite between 2015 June 8 and June 16. During this campaign, the pointing-averaged 0.3-10 keV count rate increased by a factor of 3.8, reaching the value of 58.6+/-0.10 on June 16. The latter is by 70% higher compared to the mean count rate since the start of Swift-XRT monitoring of the object. The spectra extracted from these observations fit well with the logparabola model with the photon index at 1 keV \alpha=2.23-2.34, the curvature parameter b=0.18-0.35, the position of synchrotron SED peak E_p=0.10-0.46 keV (for the Hydrogen column density fixed to the Galactic Value of 1.90\times 10^{20} cm^{-2}), the unabsorbed 2-10 keV and 0.3-10 keV fluxes of (0.61-4.78)\times 10^{-10} erg/cm^2/s and (2.16-15.91)\times 10{-10} erg/cm^2/s, respectively. In the framework of one-zone SSC models, an increased activity is also expected in the UV-radio and gamma-ray parts of the spectrum and intensive multiwavelength observations of Markarian 421 are strongly encouraged to study instable processes and emission mechanisms in this source.
