(UC Santa Cruz)
The intergalactic medium in the cosmic web
I will present observational results on the properties and distribution of the intergalactic medium (IGM) in the cosmic web. I use proprietary and public data from HST/COS UV spectroscopy of background QSOs to observe the IGM in absorption, together with galaxies mapped in emission from optical spectroscopy. By cross-matching the position of individual HI absorption line systems to those of different large scale structures (LSS) traced by galaxy distributions (e.g. voids, filaments, clusters), I characterize the IGM in different cosmic environments. I will present results on the properties of the IGM: (i) around normal star-forming and non-star-forming galaxies; (ii) within and around galaxy voids at z<0.1, that trace low- and mean-density environments respectively; and (iii) high-density environments traced by galaxy cluster pairs (intercluster filaments). With these datasets, we can directly test the modern paradigm for the cosmic web developed from cosmological simulations of structure formation.