Xiaosheng Huang (USF) “Strong Gravitational Lenses Discovered in the DESI Legacy Imaging Surveys”

ABSTRACT:We have discovered over 1500 new strong lensing candidates in the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys using residual neural networks.  The photometric redshifts of the candidate lenses are broadly distributed between 0.1 and 1.  Follow-up observations are underway.  Our Hubble Space Telescope SNAP program has confirmed all 47 of the candidates observed so far and our DESI Secondary Targets program for Year 1 will likely observe ∼400 candidate systems.  This sample will enable unprecedented tests of the cold dark matter model, e.g., by measuring the redshift evolution of the dark matter concentration and density profile slope.  Furthermore, based on DESI spectra, an optimal set of systems can be selected for a targeted search for multiply-lensed supernovae, which can be used to determine the Hubble constant.  Both objectives are highly complementary to the science goals of the DESI experiment.