1. UCL’s interests: photo-z, mass-obs calibration, systematics Granada, Sep 2010 Ofer Lahav, University College London Ofer Lahav, Stephanie Jouvel, Ole Host University College London

2. Problems for LCDM on the ‘small scales’ The MW satellites – too many in simulations? Cluster mass profiles – concentration too low in simulations? Hierachical clustering – the wrong order? Galaxies in voids- too many in simulations? Superclusters – too few in simulatons? Are we near a centre of a void?

3. Photometric and Spectroscopic surveys 2010- 2020

4. The Dark Energy Survey (DES) Proposal: –Perform a 5000 sq. deg. survey of the southern galactic cap; –300 million galaxies –Measure dark energy with LSS, clusters, WL, SN New Instrument: –2.2 FOV, 520 Mega pixel optical CCD camera + corrector Time scale: –Instrument Construction 2008-2011 Survey: –525 nights during Oct.–Feb. 2011-2016 –Area overlap with SPT SZ survey and VISTA VHS Use the Blanco 4m Telescope at the Cerro Tololo Inter-American Observatory (CTIO)

5. From Tom Broadhurst’s talk Sample selection in Color-Color Red – background Blue – background Green – cluster +~background Pink – foreground +background A370

6. The zoo of photo-z codes

7. 1.5M LRGs (“MegaZ”) photo-z code comparison SDSS HpZ+BC Le PHARE Zebra ANNz HpZ+WWC Abdalla, Banerji, Lahav & Rashkov Cf. PHAT (Hildebrandt et al. 2010)

8. Sensitivity of Cosmology to photo-z methods Baryon Fraction Omega_matter Thomas, Abdalla & Lahav 2010

9. Photo-z challenges for CLASH Cluster, fg, bg membership with probabilities Try hybrid template + training methods Biases in input photometry due to blending and lensing Optimal filters for WL (4-5) and for SL (16) Spectroscopic training sets “Self calibration”, “colour tomography”, “SB prior”

10. The End

11. Neutrino mass from MegaZ-LRG 700,000 galaxies within 3.3 (Gpc/h)^3 Thomas, Abdalla & Lahav, PRL (2010) 0911.5291 Total mass < 0.28 eV (95% CL)