Constraints on galaxy formation from the CIB-optical cross-correlation
Seunghwan Lim (CITA)
September 20, 2021
Abstract: The cosmic infrared background (CIB) is the relic of UV/optical starlight reprocessed (absorbed and re-radiated) by dust grains. With its intensity containing about half of the combined starlight ever emitted, it traces the star formation history of the Universe over a wide range of redshift, making its measurement crucial to understanding the formation and evolution of galaxies across cosmic time. Another tracer of the evolution of galaxies and large-scale structure is direct starlight observed at optical wavelengths, which accounts for roughly the other half of the starlight. Measuring cross-correlations and cross-power spectra between optical and submm wavelengths thus has great potential to comprehensively probe the build-up of stellar components over cosmic time. In this talk, I will present the signal contained in the cross-correlation between the CFIS and Herschel SPIRE submm images. Particular attention is paid to systematics that may potentially bias the measurements, including filtering and the impact of Galactic cirrus, to ensure the robustness of the measurements. We also extract the signals in diffuse light from unresolved sources separately from resolved sources. Our measurements are interpreted with a halo model framework, putting constraints on the star formation in galaxies and dark matter haloes across a wide range of masses and redshifts. With upcoming survey missions and telescopes such as the Euclid and CCAT, our methodology and analysis presented in this talk will become crucial to our understanding of the cosmic star-formation history.