| Abstract: The upcoming cosmological surveys (LSST, Euclid, Roman, SPHEREx, etc) will map the universe with a wide angular and spectral coverage. Most of the studies with large-scale surveys rely on detecting individual sources, and leave the faint, diffuse components in the extragalactic background light (EBL) largely unexplored. In this talk, I will present two two techniques that directly constrain cosmological and astrophysical information from the multi-band large-scale images without individual source detections. First, I will discuss cross correlation for EBL redshift tomography, and show prospects of constraining the EBL by cross-correlating SPHEREx and galaxy surveys. In the second part, I will introduce novel technique for probing the large-scale structures with multi-band EBL images. Without cataloging individual sources, we use a data-driven approach to simultaneously determine the spectral and spatial distribution of all emitting sources and the underlying large-scale structure traced by them. These techniques will be widely applicable to upcoming cosmological surveys, and can provide complementary information to the galaxy detection approach. |