Speaker
Description
We present a spectral study of extreme blazars (also eHBL) which are
known to exhibit hard intrinsic X-ray/TeV spectra and extreme SED peak
energies. We study four eHBLs 1ES 0120+340, RGB J0710+591, 1ES 1101-
232, 1ES 1741+196 and one HBL 1ES 2322-409 using new X-ray data from
AstroSat, together with quasi-simultaneous Fermi-LAT and other archival
multi-frequency data. Three of the eHBLs are non-variable, as is typically attributed. On the contrary, RGB J0710+591 shows spectral softening in both X-ray and GeV bands indicating a significant change in the synchrotron cut-off. Typically, a standard one-zone synchrotron self-Compton (SSC) model reproduces well eHBL SEDs, but often requires a large value of the Doppler factor and minimum electron energy. We have thus conducted a detailed investigation of the broadband SEDs under both leptonic and (lepto-)hadronic scenarios. We employ 1) a steady-state one-zone synchrotron-self-Compton (SSC) code and 2) a one-zone hadro-leptonic (OneHaLe) code. The latter is solved for two cases of the high energy emission – a pure hadronic case (proton synchrotron) and a lepto-hadronic case (synchrotron emission of secondary electrons from pion decay and Bethe-Heitler pair production). We find that all models can reproduce the
SEDs of eHBLs. For the normal HBL, SSC and proton synchrotron models
are superior to the lepto-hadronic model.
| Track | AGN |
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