Optical flux densities (R band, top panel), after correction for Galactic extinction and host galaxy contamination, compared to radio flux densities at different frequencies. Blue circles represent GASP data; red diamonds indicate data from the VLA/VLBA PCD. The vertical green line corresponds to the XMM-Newton pointing of May 16–17; the yellow strip highlights the period of Swift observations, from 2008 August 20 to October 2.