The atmospheric monitoring program of the Pierre Auger Observatory allows for a targeted measurement of atmospheric conditions shortly after the detection of air showers of special interest. This helps especially to improve the fluorescence detector reconstruction of such events. The paper reports on the implementation of the rapid monitoring program and its status. The rapid monitoring program is found to have a potential for supporting dedicated physics analyses beyond the standard event reconstruction.
Our department contributed by construction, operation and monitoring of the performance of the fluorescence detectors. The group operates the robotic telescope FRAM, which monitors the immediate atmospheric extinction and its wavelength dependence using standard stellar photometry. FRAM is the crucial and efficiently working part of the rapid monitoring program. Our team members are working with the atmospheric monitoring group for a long period, and one of us belongs to the leading authors of this paper.