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UCL’s interests: photo-z, mass-obs calibration, systematics Granada, Sep 2010

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. Problems for LCDM on the ‘small scales’. The MW satellites – too many in simulations?

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UCL’s interests: photo-z, mass-obs calibration, systematics Granada, Sep 2010

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  1. UCL’s interests:photo-z, mass-obs calibration, systematicsGranada, 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. Sample selection in Color-Color • Red – background • Blue – background • Green– cluster +~background • Pink – foreground +background A370

  6. The zoo of photo-z codes

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

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

  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-LRG700,000 galaxies within 3.3 (Gpc/h)^3 Total mass < 0.28 eV (95% CL) Thomas, Abdalla & Lahav, PRL (2010) 0911.5291

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