RSAA Colloquia / Seminars / Feast-of-Facts: Tuesday, 05 February 2019, 11:00-12:00; CSO Common Room

Matthew Baring

"A Time Evolution Picture of Multi-wavelength Flares in Blazars"

Acceleration at relativistic shocks is likely to be important in various astrophysical jet sources, including blazars and other radio-loud active galaxies. Recent work on combining multi-wavelength (MW) leptonic emission models with complete simulated distributions from shock acceleration theory has resulted in new insights into plasma conditions in blazars. This has demonstrated the ability to infer the cyclotron frequency, the plasma density and thus also the Alfven speed, thereby determining the rapidity of particle energization. An important inference was that turbulence levels decline with remoteness from jet shocks, assessed for blazars such as Mrk 501 and Bl Lac. In this talk, an overview of the MW modeling that yielded these insights is presented, including a recent extension to a two-zone, time-evolving construction. In this development, both extended, enhanced emission states from larger radiative regions, and prompt flare events from compact acceleration zones proximate to shocks are treated. An application to the LBL blazar 3C 279 is addressed: as the acceleration first proceeds and then abates, the radiative simulations obtain spectral hysteresis in the hardness-flux diagram in all wavebands. Distinctive temporal correlations and lags between radio and optical/gamma-ray bands are identified, yielding potential observational diagnostics.