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The TeV blazar 1ES 1959+650 is very bright in the X-rays again

ATel #8342; Bidzina Kapanadze (Abastumani Astrophysical Observatory at Ilia State University, Tbilisi, Georgia)
on 27 Nov 2015; 18:47 UT
Credential Certification: Bidzina Kapanadze (bidzina_kapanadze@iliauni.edu.ge)

Subjects: X-ray, Blazar

Referred to by ATel #: 9148, 9949, 10430, 10514, 10743, 11059, 11538, 15433, 16087, 16162

In ATel #8289, posted on 2015 November 16, we reported the highest historical brightness state for the TeV-detected BL Lacertae source 1ES 1959+650 recorded in the 0.3 - 10 keV energy range with the X-ray Telescope onboard the Swift satellite. Afterwards, it showed a permanent decay till 6.28+/-0.09 cts/s (November 24), followed by a flare by a factor 3.12 in 3 d. The current X-ray count rate is only by 10 per cent lower than that recorded on November 15, although the 0.3-10 keV spectrum is the most extreme ever observed for this source described well with the logparabola model (reduced Chi-square is 1.001 with 352 d.o.f.) with photon index at 1 keV a=1.54+/-0.03, curvature parameter b=0.47+/-0.05, synchrotron SED peak location Ep=3.09+/-0.12 keV, unabsorbed 0.3-10 keV flux of 7.41\times10^{-10} erg/cm^2/s (versus a=1.78+/-0.06, b=0.31+/-0.09,Ep=2.26+/0.16 keV, the 0.3-10 keV flux of 6.17\times10^{-10} erg/cm^2/s corresponding to the spectrum from the November 15 observation). In ATel #8337 posted on November 25, Trushkin et al. reported The RATAN detection of the increased radio emission from this source. 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 the intensive multiwavelength observations of 1ES 1959+650 are strongly encouraged to study instable processes and emission mechanisms in this source.