Speaker
Description
Time Domain Astronomy is living a golden era thanks to next-generation facilities extending our view of the transient Universe in a larger range of wavelengths and detecting hundreds of thousands of extra-galactic transients. Among all, the Legacy Survey of Space and Time (LSST) at the Vera C. Rubin Observatory has recently begun circulating worldwide alerts for new transient and variable sources, and will soon commence its 10-year survey of the southern sky. At the same time, numerous spectroscopic surveys are preparing for follow-up observations (e.g. SOXS), while the time-domain community synchronizes multi-wavelength and multi-messenger facilities to characterize these events in unprecedented detail. To complement this framework, the ESA Euclid mission, launched on July 2023 and not explicitly designed for variability studies, is proving to be extremely valuable in detecting high-redshift and elusive transients, thanks to repeated observations in the Euclid Deep Fields (EDFs) with deep and high-resolution optical images, and additional near-infrared (NIR) photometry and slitless spectroscopy. One of these fields (EDF-S) has been chosen for additional monitoring with Rubin, and the upcoming Roman Space Telescope (scheduled for 2027) is also considering monitoring portions of this area through its dedicated high-redshift transient program.
Within this landscape, we proposed a VST monitoring of 4 square degrees in EDF-S, as an Italian in-kind contribution for LSST. Increasing the photometric coverage provides both pre- or post- discovery observations, and high-cadence light curves to improve the classification and characterization of the newly discovered sources. This is an indispensable requirement for cosmological, progenitor, and diversity studies, as well as for the discovery of new classes of transients. Combining simultaneous multi-band light curves from VST and LSST with high-resolution optical and NIR data from Euclid will allow us to investigate transients and their host-galaxy correlations with unprecedented precision. Although the LSST is just beginning, we started our monitoring one year earlier with the pilot project VESTA (Vst-Euclid Synergies for Time-domain Astronomy) designed to provide ground-based optical support for Euclid and get ready for the VST+Euclid+Rubin synergy. We present preliminary results from VESTA, describing our analysis pipeline and the strategic transition into the formal LSST in-kind program.