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SUMMARY:Cosmography with cluster strong lensing - Professor Priyamvada Nat
 arajan\,  Yale University
DTSTART:20101208T160000Z
DTEND:20101208T170000Z
UID:TALK28326@talks.cam.ac.uk
CONTACT:Paula younger
DESCRIPTION:Current efforts in observational cosmology are focused on char
 acterizing the mass-energy content of the Universe. We present results fro
 m a geometric test based on strong lensing in galaxy clusters. Based on Hu
 bble Space Telescope images and extensive ground-based spectroscopic follo
 w-up of the massive galaxy cluster Abell 1689\, we used a parametric model
  to simultaneously constrain the cluster mass distribution and dark energy
  (DE) equation of state. Combining our cosmological constraints with those
  from X-ray clusters and the Wilkinson Microwave Anisotropy Probe 5-year d
 ata\, we find that dark matter comprises a fraction Omega_m = 0.25 ± 0.05
  of critical density and that the DE parameter wx = -0.97 ± 0.07\, both c
 onsistent with results from other methods. Inclusion of our method with al
 l other techniques available brings down the current 2 - sigma contours on
  the dark energy equation of state parameter wx by about 30%\n
LOCATION:Martin Ryle Seminar Room\, KICC
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