Cosmological implications from DESI Y1 BAO and Future Forecasts

          @misc{ pirsa_PIRSA:24070071,
            doi = {10.48660/24070071},
            url = {https://pirsa.org/24070071},
            author = {Zhang, Hanyu},
            keywords = {},
            language = {en},
            title = {Cosmological implications from DESI Y1 BAO and Future Forecasts},
            publisher = {Perimeter Institute},
            year = {2024},
            month = {jul},
            note = {PIRSA:24070071 see, \url{https://pirsa.org}}
          }
          

Abstract

We present key cosmological findings from the Dark Energy Spectroscopic Instrument (DESI)’s first year baryon acoustic oscillations (BAO) measurements. DESI's BAO provide robust measurements of the transverse comoving distance and Hubble rate across seven redshift bins, spanning a redshift range of 0.1 < z < 4.2. DESI BAO data alone align well with the flat ΛCDM model with Ωm=0.295±0.015. Paired with a baryon density prior from Big Bang Nucleosynthesis and the acoustic angular scale from the cosmic microwave background (CMB) data, we find H0=68.52±0.62 km/s/Mpc. Combined analyses with CMB anisotropies and lensing from Planck and ACT yield Ωm=0.307±0.005 and H0=67.97±0.38 km/s/Mpc. Extending the baseline model with a constant dark energy equation of state parameter, w, results in w=−0.99+0.15−0.13. In a dark energy model with time-varying equation of state parametrized by w0 and wa, combined with various supernovae data, indicate deviations from ΛCDM at significance levels up to 3.9σ. For flat ΛCDM with the sum of neutrino mass free, DESI and CMB establish an upper limit of ∑ mν <0.072 (0.113) at 95% confidence for a ∑mν>0 (0.059) eV prior. We will also show forecasts for Y3 and Y5 results as well as prospects with DESI II.