Astro Seminar Series - VIA ZOOM

Wednesday, March 3, 2021 11:30 am - 11:30 am EST (GMT -05:00)

Andreu Font-Ribera
Andreu Font-Ribera is a staff scientist at the Institut de Física d'Altes Energies (IFAE) in Barcelona. He is also an honorary researcher at University College London (UCL), where he was a lecturer in cosmology until March 2020. He has led studies of the expansion of the Universe using quasar spectra in multiple international collaborations, like the Baryon Oscillation Spectroscopic Survey (BOSS), and is now preparing similar studies with the future Dark Energy Spectroscopic Instrument (DESI).

Talk Title and Abstract:

Cosmological results from the complete eBOSS survey
 
From 2009 to 2019, the Baryon Oscillation Spectroscopic Survey (BOSS) and its extension eBOSS used the SDSS telescope to obtain precise redshifts for millions of galaxies and quasars. From the distribution of these objects we were able to get very accurate measurements of the Baryon Acoustic Oscillations (BAO) scale from redshift 0.2 to redshift 1.5. At the same time, BOSS and eBOSS obtained optical spectra of over 210 000 high redshift quasars (z>2.15) with the goal of detecting the BAO feature in the clustering of the intergalactic medium, using a phenomenon known as the Lyman alpha forest (LyaF). In this talk I will overview the final results from the LyaF dataset of eBOSS, including a 1.4% measurement of the BAO scale at z=2.33 presented in du Mas des Bourboux et al. (2020).

In the second part of the talk I will discuss the cosmological implications of the BAO measurements from BOSS/eBOSS, presented in Alam et al. (2020). This is the most comprehensive study of the expansion history of the Universe during its last 11 billion years. and it allows a detailed analysis of the spatial curvature of the Universe, the abundance of Dark Energy, the sum of the neutrino masses, and a new look at the infamous tension in the measurements of the Hubble constant.

Finally, I will also give an update on the status of the Dark Energy Spectroscopic Instrument (DESI). In the next few years DESI will increase the current spectroscopic dataset by an order of magnitude. It will provide an exquisite measurement of the expansion over cosmic time, while at the same time addressing other interesting questions: the sum of the mass of the neutrino species, properties of dark matter particles, tests of general relativity and the shape of the primordial power spectrum of density fluctuations.

Would you like to join this Zoom seminar?  Please email Donna Hayes.