A data driven framework for searching long faint astronomical high-energy transients.

HERMES (High Energy Rapid Modular Ensemble of Satellites )-Technologic and Scientific pathfinder (HERMES pathfinder) is an in-orbit demonstration consisting of a constellation of six 3U nano-satellites hosting simple but innovative X-ray detectors for the monitoring of cosmic high-energy transients. The main objective of HERMES pathfinder is to prove that an accurate position of high-energy cosmic transients can be obtained using miniaturized hardware. We present here a new tool to estimate the background, a key step to allow sensitive searches for excesses due to cosmic transients. We employ a Neural Network (NN) to estimate the background light curves on different timescales. We employ subsequently a fast change-point and anomaly detection technique to isolate observation segments where statistically significant excesses in the observed count rate relative to the background estimate exist. We test the new software on archival data from the NASA Fermi Gamma-ray Burst Monitor (GBM). We were able to confirm events in the Fermi GBM catalog, and found events, not present in Fermi GBM database, resembling solar flares, terrestrial flashes, GRBs.