| Abstract : | The broadband spectral energy distribution (SED) of Blazars is generally characterized by a double-peak structure, extending from radio to γ−ray energies. The low energy SED component is attributed to synchrotron radiation emission by relativistic electrons in the jet and the high energy component is usually interpreted as due to inverse Compton (IC) scattering of low energy radiations. 1ES 1959+650 is an extensively studied High energy peaked blazar and its synchrotron component is peaks at X-ray. The X-ray spectra of this source exhibit significant curvature and the spectrum around the peak is well described by a log-parabolic functional form. In this work, we find the spectral indices of 1ES 1959+650 before and after the synchrotron peak using Swift−XRT observations. We find a negative correlation between low-energy index and high-energy index. If blazar spectral peak energy is decided by the radiative loss, then one would expect a positive correlation between high-energy and low energy indices. Thus, this study raises serious concerns regarding the origin of the synchrotron spectral peak of the blazar 1ES1959+650. |
