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Cosmology with Spectroscopic and Photometric Redshift Surveys

Cosmology with Spectroscopic and Photometric Redshift Surveys. Ofer Lahav Department of Physics and Astronomy University College London. The post-2dF/SDSS/WMAP3 universe The 2MASS Redshift Survey The Photo-z MegaZ-LRG The Dark Energy Survey .

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Cosmology with Spectroscopic and Photometric Redshift Surveys

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  1. Cosmology with Spectroscopic and Photometric Redshift Surveys Ofer Lahav Department of Physics and Astronomy University College London • The post-2dF/SDSS/WMAP3 universe • The 2MASS Redshift Survey • The Photo-z MegaZ-LRG • The Dark Energy Survey

  2. Cosmology with Spectroscopic and Photometric Redshift Surveys Ofer Lahav Department of Physics and Astronomy University College London • The post-2dF/SDSS/WMAP3 universe • The 2MASS Redshift Survey • The Photo-z MegaZ-LRG • The Dark Energy Survey

  3. Cosmology in 1986 • Galaxy redshift surveys of thousands of galaxies (CfA1, IRAS) • CMB fluctuations not detected yet • Peculiar velocities popular (7S) • “Standard Cold Dark Matter” m = 1, =0 H0 = 50 km/sec/Mpc = 1/(19.6 Gyr)

  4. Redshift Surveys

  5. The evolution of the Cosmic Web in the past 20 years SDSS CfA Great Wall Great Attractor 2dFGRS

  6. 2dFGRS PhD students & collaborators Spectral classification (PCA): S. Folkes, S. Ronen, D. Madgwick Biasing from 2dF+CMB: S. Bridle Neutrino mass: O. Elgaroy Wiener Reconstruction: P. Erdogdu Stochastic Biasing: V. Wild Testing the halo model: A. Collister

  7. From 2dF+CMB (6 parameter fit): m=0.23 §0.02 Cole et al. 2005

  8. WMAP3 m = 0.24 +-0.04 8 = 0.74 +-0.06 n = 0.95 +-0.02  = 0.09 +-0.03

  9. F 2MASS Galactic chart (Tom Jarrett)

  10. 2MASS and follow-ups • 2MASS: all sky, 1.5M galaxies (Ks < 13.5) • 2MRS: all sky, 25K redshifts (Ks <11.25) • 6dF (Southern hemisphere): 150K redshifts (Ks < 12.75) and 15K Dn-sigma distances

  11. 2MRS Dipole directions Erdogdu et al. 2005

  12. Dipoles in the Local Group Frame Flux weighted Number weighed m0.6 /bL = 0.40+- 0.10 12o @ 50 Mpc/h 21o @ 130 Mpc/h Erdogdu, Huchra, Lahav et al., Astro-ph/0507166

  13. Dipole from X-ray clusters Shapley Kocevski, Mullis & Ebeling, astro-ph/0403275

  14. Wiener Reconstruction of density and velocity fields Erdogdu, OL, Huchra et al

  15. Photometric redshift • Probe strong spectral features (4000 break) • Difference in flux through filters as the galaxy is redshifted.

  16. ANNz - Artificial Neural Network z = f(m,w) Output: redshift Input: magnitudes Collister & Lahav 2004 http://www.star.ucl.ac.uk/~lahav/annz.html

  17. Example: SDSS data (ugriz; r < 17.77) ANNz (5:10:10:1) HYPERZ Collister & Lahav 2004

  18. Clustering on Gpc scale LRG photo-z Padmanabhan et al Astro-ph/0605302 Blake, Collister, Bridle, Lahav Astro-ph/0605303

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

  20. photo-z bins Collister et al.

  21. Clustering in photo-z space

  22. Angular power spectra vary 4 parameters Non-linear P(k) Minimum fitted multipole Linear P(k)

  23. Cosmological parameter fits separate photo-z slices Marginalize over: Fix: Best fit - all slices Best fit - 1 slice

  24. Cosmology from LRG photo-z(Blake et al.) b/ m = 0.14+-0.04 (cf. 0.18 +- 0.01 from WMAP3) m = 0.27+-0.04 (cf. 0.24+-0.03 from WMAP3) .

  25. Excess Power on Large Scales? Blake et al. 06 Padmanabhan et al. 06

  26. The origin of excess power • Photo-z systematics? • Window functions? • Cosmic variance? • Large scale redshift distortion? • Large scale biasing? • Gauge transformations? • Modified early universe physics?

  27. Probing Dark Matter & Dark Energy • Through the history of the expansion rate: H2(z) = H20 [M (1+z) 3 + DE (1+z) 3 (1+w) ] (flat Universe) matter dark energy (constant w) P = w  • Comoving distance r(z) =  dz/H(z) • Standard Candles dL(z) = (1+z) r(z) • Standard Rulers dA(z) = (1+z)1 r(z) • Standard Population (volume) dV/dzd = r2(z)/H(z) • The rate of growth of structure also determined by H(z) and by any modifications of gravity on large scales

  28. Spectroscopy FMOS KAOS SKA SDSS ATLAS Supernovae CSP DES LSST CFHTLS Pan-STARRS JDEM/ SNAP Clusters AMI APEX SPT DES SZA AMIBA ACT CMB WMAP 2/3 WMAP 6 yr Planck Planck 4yr Surveys to measure Dark Energy 2010 2015 2005 Imaging CFHTLS SUBARU DES LSST SKA SDSS ATLAS KIDS VISTA JDEM/ SNAP Pan-STARRS 2005 2015 2010

  29. Dark Energy Task Force Rocky Kolb et al.

  30. 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 Cost: $20M

  31. Sources of uncertainties • Cosmological (parameters and priors) • Astrophysical (e.g. cluster M-T, biasing) • Instrumental (e.g. “seeing”)

  32. Dark Energy Survey Collaboration • Fermilab-Camera, Survey Planning, and Simulations • U Illinois-Data Management, Data Acquisition, SPT • U Chicago-SPT, Simulations, Corrector • LBNL-CCD Detectors • CTIO-Telescope & Camera Operations • Spain: Barcelona, Madrid – Electronics, Simulations • UK: UCL, Portsmouth, Cambridge, Edinburgh – Optics, Science Analysis

  33. The Dark Energy Survey UK Consortium (I) PPARC funding: O. Lahav (PI), P. Doel, M. Barlow, S. Bridle, S. Viti, J. Weller (UCL), R. Nichol (Portsmouth), G. Efstathiou, R. McMahon, W. Sutherland (Cambridge) J. Peacock (Edinburgh) Submitted a proposal to PPARC in February 2005 requesting £ 1.5 M for the fabrication and testing of the optical corrector lenses. In March 2006, PPARC Council announced that it “will seek participation in DES”. (II) SRIF3 funding: R. Nichol, R. Crittenden, R. Maartens, W. Percival (ICG Portsmouth) K. Romer, A. Liddle (Sussex) Partial funding of the glass blanks for the UCL DES optical work These scientists will work together through the UK DES Consortium. Other DES proposals are under consideration by US and Spanish funding agencies.

  34. Dark Energy Survey Instrument 3.5 meters Camera 1.5 meters Scroll Shutter Filters Optical Lenses New Prime Focus Cage, Camera, and Corrector for the Blanco 4m Telescope 500 Megapixels, 0.27”/pixel Project cost: ~20M$ (incl. labor)

  35. VDES proposal DES (griz) DES+VISTA(JK)

  36. Spectroscopic Redshift Training Sets for DES

  37. Assumptions: Clusters: 8=0.75, zmax=1.5, WL mass calibration (no clustering) BAO:lmax=300 WL:lmax=1000 (no bispectrum) Statistical+photo-z systematic errors only Spatial curvature, galaxy bias marginalized Planck CMB prior w(z) =w0+wa(1–a) 68% CL DES Forecasts: Power of Multiple Techniques geometric+ growth Clusters if 8=0.9 geometric Frieman, Ma, Weller, Tang, Huterer, etal

  38. Baryon Wiggles as Standard Rulers(for $60M, or less?)

  39. Summary Many observations support the L-CDM model, but… - What is the Dark Matter? - What is the Dark Energy? - Why are their amounts similar? If in 10 years it turns out that w=-1 to within 1%, then what?? New Physics? The Anthropic Principle? Multiverse?

  40. Globalisation and the New Astronomy • One definition of globalisation: “Adecoupling of space and time - emphasising that with instantaneous communications, knowledge and culture can be shared around the world simultaneously.”

  41. Globalisation and the New Astronomy • How is the New Astronomy affected by globalisation? Free information (WWW), big international projects, numerous conferences, telecons… • Recall the Cold War era: Hot Dark Matter/top-down (Russia) vs. Cold Dark Matter/bottom-up (West) • Is the agreement on the `concordance model’ a product of globalisation?

  42. Happy Birthday, Bernard!

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