Real time aperture photometry with Cherenkov telescope array

This thesis concerns the detection of transient phenomena on very short timescales exploiting the Cherenkov Telescope Array facility. A timely analysis of transients is crucial in current multi-messenger astrophysics and the Real-Time Analysis system takes care to analyze the data during the observation time and to generate scientific alerts when the detections are confirmed. In this work the gamma-ray analysis maximum likelihood and aperture photometry methods are detailed and two different tools (ctools and RTA aperture photometry tool) are compared. The RTA aperture photometry tool, implemented in this work, will provide a reliable and quick method to evaluate the detection significance and estimate the flux of the target in short time observations. It is described in detail. The test results for a Crab-like source and a short GRB afterglow are shown and the detection time thresholds are highlighted.