Multiwavelength variability analysis of the blazar 3C 273

Abstract

We analysed the broadband light curves of the flat spectrum radio quasar (FSRQ) 3C 273 between September 2008 and August 2012. The discrete correlation function (DCF) probed the correlation between light curves at different frequencies. This method showed a correlation between the gamma-ray emission and the radio mm-emission, as well as with the optical polarisation. This result indicated a non-thermal origin for the gamma-ray emission. Using the time lags from the correlation results, we found the relative separation distance between the gamma-ray and the radio emission regions. Our results showed that the gamma-ray emission is coming from a compact region close to the core (1.2 ± 0.9 pc from the jet apex). The X-ray emission has two components, one coming from the jet through inverse Compton mechanisms while the other is coming most probably from the hot corona through reflection off the disk. The radio emission at high frequencies is coming from regions downstream the jets and is leading the emission at cm-radio bands.