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Cosmic Structures: Challenges for Astro-Statistics

Cosmic Structures: Challenges for Astro-Statistics. * Data compression – e.g. P(k) * Features in P(k) * Parameter estimation and model selection * Beyond the 2-point statistic * The big questions: dark matter, dark energy, galaxy formation. Ofer Lahav

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Cosmic Structures: Challenges for Astro-Statistics

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  1. Cosmic Structures:Challenges for Astro-Statistics • * Data compression – e.g. P(k) • * Features in P(k) • * Parameter estimation and model selection • * Beyond the 2-point statistic • * The big questions: • dark matter, dark energy, galaxy formation Ofer Lahav Department of Physics and Astronomy University College London

  2. F 2MASS Galactic chart (Tom Jarrett)

  3. Redshift Surveys

  4. The Cosmic Web SDSS CfA Great Wall Great Attractor 2dFGRS

  5. Is the universe a fractal?A short answer: NO N(<R) / RD D=1.2

  6. clumpiness Small scales

  7. Correlation Function per Type dP / n [1+(r)] dV (r) = (r/r0)- Why a power law? different slopes for blue and red explained by different halo Occupation numbers Madgwick et al. 03

  8. Halo model for LSS Picturecredit: Cooray & Sheth (2002)

  9. The halo model – the ‘new biasing’ P(k) = Plin+Phalo Truncated NFW fit with C=2.4§ 0.2 using 2dF Groups Collister & Lahav, astro-ph/0412516

  10. Neutrinos decoupled when they were still relativistic, hence they wiped out structure on small scales 112 neutrinos per cm3 CDM+HDM WDM CDM From 2dF  < 0.04 ; M < 1.8 eV (Elgaroy & OL 2003) From Ly-a+SDSS +CMB M < 0.17 eV (Seljak et al. 2006)

  11. Mock Universes: Models vs. Epoch

  12. Same amplitudes, different phases Chiang & Coles 2000

  13. Non-Gaussianity in LSS • Guassian density contrast pdf will turn into (roughly) a log-normal pdf. • Gravity is an amplifier: the rich gets richer the poor gets poorer • Needed: non-G tests, shape finders

  14. CiC 2dF early type Wild et al 2004

  15. Minkowski functionals

  16. ( ) 2

  17. Wavelet MF V3 applied to 2dF Martinez et al.

  18. Are the 2dFGRS superclustersanomalous? 7 Abell clusters 77 groups (>8) 20 Abell clusters 93 groups (>8) Baugh et al., Erdogdu et al., Murphy & OL

  19. MegaZ-LRG *Training on ~13,000 2SLAQ*Generating with ANNz Photo-z for ~1,000,000 LR over 5,000 sq deg z = 0.046 Collister, Lahav, Blake et al.

  20. power spectra out to 1 Gpc vary 4 parameters Non-linear P(k) Minimum fitted multipole Linear P(k) Blake et al., astro-ph/0605303

  21. Baryon Wiggles as Standard Ruler

  22. The Dark Energy Survey • 4 complementary techniques: * Cluster counts & clustering * Weak lensing * Galaxy angular clustering * SNe Ia distances Build new 3 deg2 camera on the CTIO Blanco 4m Construction 2005-2009 Survey 2009-2014 (~525 nights) 5000 deg2g, r, i, z 300, 000, 000 galaxies with photo-z Science goal: w to ~5-10% on each technique

  23. LSS - The Steps Ahead * Spetcroscopic and photometric Surveys Of 106 – 108 galaxies * Beyond the 2-point statistic: higher meoments, MF, shape finders, phases… * The interplay with galaxy formation * Dark energy surveys (BAO, WL) * The VO infra-structure

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