Light curves of AB Dor A observed on 25 Nov. 2009: a) 5.5 GHz radio flux from ATCA observations binned to 120 s; b) and c) Ca ii K flux and Hα equivalent widths calculated from UVES spectra; d) OM light curve; e) EPIC (combined MOS and pn) light curve; f) EPIC hardness ratio. Light curves d) to f) are binned to 100 s. The vertical lines in panel e) indicate the time segment corresponding to the events discussed in the article. Plotted at the top is the arbitrary rotation phase.