Identified radio flares at centimeter wavelengths (data points) from the Proxima Centauri system against orbital phase of their emission peaks. The dashed vertical lines correspond to the quadrature positions. During our ATCA observationstwo short flares, F1 and F2 (Fig. 2 and Sect. 3.2), and a long-lasting burst, LB (Fig. 2), were observed. The flares labeled “Lim” and “Slee” correspond to the centimeter wavelength flares observed in 1991 and 2000 by Lim et al. (1996) and Slee et al. (2003) (see Sect. 4.3). The error bars indicate the total uncertainties on the phases of the flares, including the contributions due to the uncertainty on the time of the flare peak, on the orbital period, and on the absolute phase reference. The Slee flare peaked before the start of those observations, and only an upper limit to its phase is known. This is indicated by the blue arrow.