Coffee talks
Friday 30/05/2025 @ 11:30, Sala riunioni quarto piano e on line (meet.google.com/sue-bwvk-axf)
Marika Giulietti (IRA-INAF, Bologna), "SEMPER: A novel semi-empirical model for the radio emission of star-forming galaxies at 0<z<5"
Semi-empirical models have recently proven to be valuable tools for studying galaxy formation and evolution. Rather than deriving small-scale baryon cycle physics from first principles, these models rely on empirical relations between spatially averaged galaxy properties. Their strength lies in minimal assumptions and parameters calibrated on observations, making them data-driven, computationally efficient, and complementary to ab initio numerical simulations. We developed the Semi-EMPirical model for Extragalactic Radio emission (SEMPER) to predict radio luminosity functions and number counts at 1.4 GHz and 150 MHz for star-forming galaxies (SFGs). SEMPER combines redshift-dependent galaxy stellar mass functions from deep NIR data with state-of-the-art empirical relations, such as the galaxy main sequence and the far-IR/radio correlation, to improve understanding of the radio properties of massive, high-redshift galaxy populations. The model shows excellent agreement with observations at 1.4 GHz and 150 MHz from recent radio surveys conducted with interferometers such as the JVLA and LOFAR, along with results from previous semi-empirical models and simulations. Notably, SEMPER naturally predicts the existence of massive, dust-obscured galaxies already in place at high redshift (z >~ 3.5), in line with recent findings from JWST and consistent with previously identified radio-selected, optical/NIR-dark sources. Our predictions provide an excellent benchmark for upcoming updates from JWST and future ultra-deep radio surveys planned with SKA and its precursors, serving as a valuable tool for a deeper understanding of galaxy formation and evolution across cosmic time.