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SUMMARY:Studying the Expansion of the Universe with quasar spectra - Andre
 u Font-Ribera (UCL)
DTSTART:20181126T130000Z
DTEND:20181126T140000Z
UID:TALK109462@talks.cam.ac.uk
CONTACT:Tobias Baldauf
DESCRIPTION:From 2009 to 2014\, the Baryon Oscillation Spectroscopic Surve
 y (BOSS) used the SDSS telescope to obtain spectra of 1.5 million galaxies
  to get very accurate measurements of the Baryon Acoustic Oscillations (BA
 O) scale at redshift z ~0.5. At the same time\, BOSS observed over 184 000
  high redshift quasars (z>2.15) with the goal of detecting the BAO feature
  in the clustering of the intergalactic medium\, using a technique known a
 s the Lyman alpha forest (LyaF). In this talk I will overview the final re
 sults from the LyaF working group in BOSS\, including the measurement of B
 AO at z=2.4 both from the auto-correlation of the LyaF (Bautista et al. 20
 17)\, and from its cross-correlation with quasars (du-Mas-des-Bourboux et 
 al. 2017). From the combination of these studies we are able to measure th
 e expansion rate of the Universe 11 billion years ago with a 2% uncertaint
 y. \nStarting in 2019\, the Dark Energy Spectroscopic Instrument (DESI) wi
 ll increase this data set by an order of magnitude. DESI will provide an e
 xquisite measurement of the expansion over cosmic time\, while at the same
  time addressing other interesting questions: the sum of the mass of the n
 eutrino species\, properties of dark matter particles\, tests of general r
 elativity and the shape of the primordial power spectrum of density fluctu
 ations.
LOCATION:CMS\, Pav. B\, CTC Common Room (B1.19) [Potter Room]
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