DescriptionThe LAT instrument onboard the Fermi satellite is monitoring the universe in high-energy (~GeV) gamma rays. The data is made available to the community only a few hours after the photons have been recorded. FLaapLUC is an automatized pipeline that analyzes the public Fermi-LAT data in search for flaring activity of a list of pre-defined sources.
Currently, the used source list has been developed with the H.E.S.S. collaboration and is thus focusing on sources visible from the Southern hemisphere. An extension to an extended source list is under discussion.
FLaapLUC comprises a two-step processing of the data: twice a day an aperture photometric analysis is performed around each source using the most recent photon list from Fermi-LAT. This basically assumes that the data set, within 1 degree around the source, is background-free. As soon as the source flux is surpassing a threshold (set to 3sigma above the long-term flux average), a dedicated likelihood analysis of the ROI is started.
In Astro-COLIBRI, these two steps are represented by two different notification types: 'alerts' (i.e. standing for the aperture photometry analysis) and 'analysis results' (i.e. reporting the results from the likelihood analysis). The produced lightcurves, SEDs and a figure showing the energy of the recorded photons as function of time are stored within the Astro-COLIBRI databases and are updated after every new FLaapLUC processing.