Speaker
Description
We have performed a detailed analysis of the X-ray spectra of the blazar Mkn 421
using Swift-XRT observations taken between 2005 and 2020, to quantify the correla-
tions between spectral parameters for different models. In an earlier work, it has been
shown that such spectral parameter correlations obtained from a single short flare
of duration ∼ 5-days of Mkn 421, can be used to distinguish spectrally degenerate
models and provide estimates of physical quantities. In this work, we show that the
results from the long-term spectral parameter correlations are consistent with those
obtained from the single flare. In particular, that the observed spectral curvature is
due to maximum cutoff energy in the particle distribution is ruled out. Instead, models
where the curvature is due to the energy dependence of escape or acceleration time-
scale of the particles are favored. The estimated values of the physical parameters for
these models are similar to the ones obtained from the single flare analysis and are
somewhat incompatible with the physical assumption of the models, suggesting that
more complex physical models are required. The consistency of the results obtained
from the long and short-term evolution of the source, underlines the reliability of the
technique to use spectral parameter correlations to distinguish physical models.
