Imaging the Cosmic Web

          @misc{ pirsa_PIRSA:25070037,
            doi = {10.48660/25070037},
            url = {https://pirsa.org/25070037},
            author = {Martin, Chris},
            keywords = {Cosmology},
            language = {en},
            title = {Imaging the Cosmic Web},
            publisher = {Perimeter Institute},
            year = {2025},
            month = {jul},
            note = {PIRSA:25070037 see, \url{https://pirsa.org}}
          }
          

Abstract

The intergalactic medium (IGM) represents the dominant reservoir of baryons at high red- shift, traces the architecture of the cosmic web dominated by dark matter, and fuels on-going galaxy evolution. Using a purpose-built instrument, with nod-and-shuffle and dual-field subtraction, we have detected, for the first time, an emission Lyman α forest (ELAF). The emission forest is highly extended, shows filamentary morphology with filaments connecting galaxies, exhibits statistics like the absorption Lyman α forest, displays spectra resembling the absorption forest, and is correlated with galaxy-traced overdensities consistent with bias like dark matter. We conclude that the ELAF may provide a new tool for tracing a significant fraction of the cosmic web of baryons and dark matter. Finally, I will present status of the STABLE Cosmic Web Imager (SCWI) program, a Brinson Exploration Hub balloon experiment, focused on emission from the Circum-QSO, the Circum-Galactic Medium, and the cosmic web. SCWI offers the opportunity to image the cosmic web in the local universe for the first time, and compare its properties to those at high redshift.