FACT - Database-based Analysis and Spectrum Calculations

The First G-APD Cherenkov Telescope (FACT) is located at the Observatory Roque de los Muchachos on the Canary island La Palma. It uses the imaging air Cherenkov technique to detect gamma rays. With the help of silicon based photosensors in the camera, FACT is an ideal instrument to monitor a small sample of sources with a good time coverage. The automatic operation of the telescope allows an increase of the duty cycle of the instrument. An SQL database is part of the automatic analysis chain, where data on an event basis are stored. This way of storing the data has a several advantages. It can provide easy web-access to all data with no need of creating different user accounts for the analysers and without using special software. The data selection is done via simple queries to the database. This allows very flexible and powerful queries with, for example, user-defined time binning or background suppression. By using observed and simulated events, the complete analysis chain can be done, including the calculation of the measured energy spectrum. This could also be implemented to the Quick-Look Analysis to provide spectral information during the night with a low latency.