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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? - PowerPoint PPT Presentation
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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?
• 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?
Photometric and Spectroscopic surveys 2010-
2020
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 Blanco4m Telescope at the Cerro TololoInter-American Observatory (CTIO)
From Tom Broadhurst’s talk
Sample selection in Color-Color
• Red – background• Blue – background• Green – cluster
+~background• Pink – foreground
+background
A370
The zoo of photo-z codes
1.5M LRGs (“MegaZ”) photo-z code comparison
SDSS
HpZ+BC
Le PHARE
Zebra
ANNz
HpZ+WWC
Abdalla, Banerji, Lahav & RashkovCf. PHAT (Hildebrandt et al. 2010)
Sensitivity of Cosmology to photo-z methods
• Baryon Fraction
Omega_matter
Thomas, Abdalla & Lahav 2010
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”
The End
Neutrino mass from MegaZ-LRG700,000 galaxies within 3.3 (Gpc/h)^3
Thomas, Abdalla & Lahav, PRL (2010) 0911.5291
Total mass < 0.28 eV (95% CL)
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