Physics Colloquium - From Reionization to Dark Matter with Quasar Absorption Lines

Event Date: 

Tuesday, October 28, 2014 - 4:00pm

Event Location: 

  • Broida 1640

Event Contact: 

Speaker:

George Becker, Kavli Institute for Cosmology, University of Cambridge

Abstract:

Distant quasars are among our most powerful probes of cosmic structure.  The absorption lines in quasar spectra trace the baryons in deep space from galactic to cosmological scales.  The “forest” of lines produced by hydrogen, in particular, encodes the evolution of intergalactic matter over more than 90% of cosmic history.  I will present new insights gained from quasar absorption lines into two outstanding issues: (1) When and how was the Universe (re-)ionized by the first luminous objects? and (2) How cold (or warm) is dark matter?  These projects combine data from the largest optical telescopes with advanced numerical simulations, and suggest new approaches to studying the distant Universe.