Detection of VHE gamma-ray transients with monitoring facilities

The observation of Very High Energy gamma rays (VHE, E > 100 GeV) led us to the identification of extremely energetic processes and particle acceleration sites both within our Galaxy and beyond. We expect that VHE facilities, like CTA, will explore these sources with an unprecedented level of detail. However, the transient and unpredictable nature of many important processes requires the development of proper monitoring strategies, to observe them. With this study, we estimate the properties of VHE transients that can be effectively detected by monitoring facilities. We use data collected by the Fermi-LAT instrument, during its monitoring campaign, to select events that are likely associated with VHE emission. We use this sample to estimate the frequency, the luminosity and the time-scales of different transients, focusing on blazar flares and Gamma Ray Bursts (GRBs). We discuss how the balance between Field of View, sensitivity and duty cycle of an observatory affects the likelihood to detect transients that occur at the inferred rates and we conclude describing the contribution that current and near-future monitoring facilities can bring to the identification and study of VHE transient emission.