A hydrosimulations-based approach to relate the Fast Radio Burst dispersion measure -- redshift relation to the suppression of matter power spectrum

          @misc{ pirsa_PIRSA:25080007,
            doi = {10.48660/25080007},
            url = {https://pirsa.org/25080007},
            author = {Sharma, Kritti},
            keywords = {},
            language = {en},
            title = {A hydrosimulations-based approach to relate the Fast Radio Burst dispersion measure -- redshift relation to the suppression of matter power spectrum},
            publisher = {Perimeter Institute},
            year = {2025},
            month = {aug},
            note = {PIRSA:25080007 see, \url{https://pirsa.org}}
          }
          

Abstract

The effects of baryonic feedback on matter power spectrum are uncertain. Upcoming large-scale structure surveys require percent-level constraints on the impact of baryonic feedback effects on the small-scale ($k \gtrsim 1\,h\,$Mpc$^{-1}$) matter power spectrum to fully exploit weak lensing data. The sightline-to-sightline variance in the fast radio bursts (FRBs) dispersion measure (DM) correlates with the strength of baryonic feedback and offers unique sensitivity at scales upto $k \sim 100\,h\,$Mpc$^{-1}$. We analytically compute the variance in FRB DMs using the electron power spectrum, which is modeled as a function of cosmological and feedback parameters in IllustrisTNG suite of simulations in CAMELS project. We demonstrate its efficacy in capturing baryonic feedback effects across several simulation suites, including SIMBA and Astrid. We show that with 10,000 FRBs, the suppression of the matter power spectrum can be constrained to percent-level precision at large scales (k < 1 h/Mpc) and ~10% precision at small scales (k > 10 h/Mpc). Insights into the impact of baryons on the small-scale matter power spectrum gained from FRBs can be leveraged to mitigate baryonic uncertainties in cosmic shear analyses.