Speaker
Description
With its high duty cycle (>98%) and wide field of view (`2sr) and good sensitivity (~1.3%CU), the Large High Altitude Air Shower Observatory - Water Cherenkov Detector Array (LHAASO-WCDA) can conduct an unbiased gamma-ray sky survey in the energy range from a few hundred GeV to 100 TeV. The sensitivity of WCDA is as high as a few percent of Crab Units(CU), which allows us to monitor the VHE variability of blazars. The LHAASO Collaboration has developed an online monitoring program to monitor the extragalactic Very High Energy(VHE) flare in the WCDA’s field of view. Once a flare exceeding the threshold is detected, an alert will be sent to other instruments automatically, and a follow-up multiwavelength observation could be carried out. After the entire system was set up by the end of 2023, a series of flares from 1ES 1959+650, IC 310 and Mrk421 have been detected. These events have also attracted widespread attention and subsequent observations within the community. In this talk, I will introduce the system operation, including candidate sources, the methods, and current status of the monitor, as well as some astrophysical implications.
