Infrared variability of the BL Lacertae object OJ287 since its outburst in 1983

In early 1983, OJ 287 was seen to undergo an outburst in its optical and infrared emission. The authors have monitored the near-infrared emission since the outburst. The fluxes have fluctuated considerably, with the lowest recordings being an order of magnitude less than those measured during the outburst. The authors have found an excellent correlation between infrared flux and spectral index; as the source gets fainter the spectrum gets steeper, and vice versa. They interpret this in terms of outbursts being due to injection or reacceleration of electrons with a constant energy index which subsequently steepens as the electrons are affected by radiation losses