Serendipitous and targeted mm/sub-mm transient searches with wide-FOV telescope

Abstract: The millimeter/sub-millimeter (mm/sub-mm) sky remains a rich but under-explored frontier for transient and variable phenomena. A wide-field, high-sensitivity instrument with a large aperture and degree-scale field of view would open this regime, enabling both systematic survey monitoring and rapid-response follow-up. Key science opportunities include Galactic Plane monitoring and surveys to discover and characterize time-variable emission from young stellar objects, magnetically active and flaring stars, compact binaries, and explosive events, as well as prompt responses to multi-messenger alerts with large localization regions (e.g., gravitational-wave triggers). Multi-band capability, rapid slewing, and high sensitivity are essential to probe energetic processes such as jet launching, relativistic shocks and accretion flows in unprecedented detail. While long-term monitoring is well established at radio and optical/infrared wavelengths, mm/sub-mm observations uniquely bridge the spectral gap between these regimes, directly probing obscured environments that are inaccessible elsewhere. Large-scale monitoring programs will yield legacy datasets crucial for population studies through the 2040s and beyond.