High energy astrophysical phenomena, such as blazars, gamma-ray burst and pulsar wind nebulae, show emission signatures of non-thermal particle distribution indicating efficient particle acceleration. They also share a common feature --- strong magnetic fields with magnetic energy content of the order of the rest mass energy.
Under such conditions relativistic magnetic reconnection (RMR) is the most efficient mechanism for particle acceleration. By means of kinetic simulations, previous studies of steady-state RMR have demonstrated its ability for producing highly energetic non-thermal particle distributions.
These energetic particles are mainly contained within plasmoids, also known as magnetic islands.
A chain of plasmoids with stochastic properties is continuously generated by tearing instability within the reconnecting layer.
Plasmoid statistics have been used to model the broad band and highly variable emission observed in blazars.
However in the regime of high emission efficiency, radiative cooling influences particle dynamics, and thus it may also affect plasmoids properties.
We present the results of 2D PIC simulations of steady state RMR which include synchrotron radiation reaction and calculation of the resulting emission signatures.
We show that radiative cooling affects mainly the dense cores of large plasmoids, which are also the main sites of synchrotron emission.
Synchrotron lightcurves show rapid bright flares that can be identified as originating from tail-on mergers between a small/fast plasmoid and a large/slow target.