Particle and Astroparticle Physics Colloquium Hamburg

DESI 2024: Cosmological results from measurement of Baryon Acoustic Oscillations

by Seshadri Nadathur (University of Portsmouth)

Auditorium (DESY Hamburg)


DESY Hamburg


I will present a summary of the measurements of Baryon Acoustic Oscillations in the data release 1 (DR1) of the Dark Energy Spectroscopic Instrument (DESI) and the cosmological constraints that can be derived from these. DESI BAO provide robust measurements of the transverse comoving distance and Hubble rate, relative to the sound horizon, using over 6 million extragalactic objects in seven redshift bins, over the redshift range 0.1 < z < 4.2, and increasing the previous largest such dataset by a factor of 3. Within a flat Lambda cold dark matter (LCDM) background model, these results are consistent with those from the CMB. In combination with external priors, we measure the Hubble constant H_0 to 1% precision or better. We derive an upper limit on the sum of the neutrino masses of Mν < 0.072 eV (95% confidence) – I will explain how this limit depends on priors and assumptions about the background expansion. Most interestingly, we find tentative evidence for the dark energy equation of state varying with time from the combination of DESI BAO, CMB and type Ia supernovae – these joint constraints reject the cosmological constant LCDM model with significances of between 2.5 and 3.9 sigma, depending on the dataset used.

We invite you to join the presentation in the DESY auditorium. We also offer a webcast:

Meeting ID: 996 1652 8733 
Meeting Password: 733220