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Testing the Dark Energy Paradigm Piran@60

Testing the Dark Energy Paradigm Piran@60. Ofer Lahav University College London. - Collaborating with Tsvi Brief History of D a rk Energy The Dark Energy Survey and Euclid The Next Paradigm Shift?. Less-extreme papers with Tsvi. Treyer et al. (1998) XRB LSS

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Testing the Dark Energy Paradigm Piran@60

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  1. Testing the Dark Energy ParadigmPiran@60 Ofer Lahav University College London • -Collaborating with Tsvi • Brief History of Dark Energy • The Dark Energy Survey and Euclid • The Next Paradigm Shift?

  2. Less-extreme papers with Tsvi Treyer et al. (1998) XRB LSS Scharf et al. (2000) the XRB dipole (1990) (1997)

  3. The Chequered History of theCosmological Constant  * The old CC problem: Theory exceeds observational limits on  by 10120 ! * The new CC problem: Why are the amounts of Dark Matter and Dark Energy so similar?

  4. Dark Energy Pre-SNIa • Peebles (1984) advocated Lambda • APM result for low matter density (Efstathiou et al 1990) • Baryonic fraction in clusters (White et al. 1993) • The case for adding Lambda (Ostriker & Steinhardt 1995) • Others…

  5. The Dark Energy problem: 10, 90 or 320 years old? The weak field limit of GR: F = -GM/r2 + /3 r X * “I have now explained the TWO principle cases of attraction… which is very remarkable” Isaac Newton, Principia (1687) Lucy Calder & OL A&G Feb 08 issue http://www.star.ucl.ac.uk/~lahav/CLrev.pdf (revised)

  6. “Evidence” for Dark Energy Observational data • Type Ia Supernovae • Galaxy Clusters • Cosmic Microwave Background • Large Scale Structure • Gravitational Lensing • Integrated Sachs-Wolfe Physical effects: • Geometry • Growth of Structure Both depend on the Hubble expansion rate: H2(z) = H20 [M (1+z) 3 + DE (1+z) 3 (1+w) ] (flat)

  7. Standard rulers

  8. Baryonic Acoustic Oscillations Comving distance Harmonic l SDSS Luminous Red Galaxies Density fluctuations CMB WMAP Temperature fluctuations z=0.5 z=1000

  9. The Integrated Sachs-Wolfe Effect potential depth changes as cmb photons pass through gravitational potential traced by galaxy density In EdS the potential is constant with time, hence no ISW effect. An effect is expected in a universe with DE, and it can be detected by cross-correlating the CMB with galaxy maps (Crittenden et al).

  10. Cross-correlation of WMAP and 2MASS CCF consistent with no correlation, as well as with < 0.89 (95% CL) Rassat, Land, OL, Abdalla (2006); Francis & Peacock (2009)

  11. Probing the Geometryof the Universe with Supernovae Ia ‘Union’ SN Ia sample (Kowalski et al. 2008)

  12. In 3 Dimensions Massey et al. 2007

  13. Spectroscopic Surveys SDSS CfA 2dFGRS

  14. Deviations from standard GR? Lensing sensitive to the sum of potentials Bean (2009) using Cosmos2007 Soon with Cosmos2009

  15. The Future of the Local Universem =0.3 LCDM a = 1 (t= 13.5 Gyr) LCDM a = 6 (t= 42.4 Gyr) OCDM a = 1 (t= 11.3 Gyr) OCDM a = 6 (t= 89.2 Gyr) Hoffman, OL, Yepes & Dover 0705.4477

  16. Galaxy Surveys2010-2020 Photometric surveys: DES, Pan-STARRS, HSC, Skymapper, PAU, LSST, Euclid (EIC), JDEM(SNAP-like), … Spetroscopic surveys: WiggleZ, BOSS, BigBOSS, hetdex, WFMOS/Sumire, Euclid (NIS), JDEM (Adept-like), SKA, …

  17. Photometric redshifts z=0.1 z=3.7 • Probe strong spectral features (e.g. 4000 break) • Template vs. Training methods

  18. MegaZ-LRG Photoz scatter of 0.04 • Input: 10,000 galaxies with spectra • Train a neural network • ANNz, Collister & Lahav 2004 • Output: 1,000,000 photo-z • Collister, Lahav et al. 2007 • Update using 6 photo-z methods • *Abdalla et al. 2009 3 (Gpc/h)3: the largest ever galaxy redshift survey!

  19. SDSS 1.5M LRGs (“MegaZ”) photo-z code comparison ANNz HpZ+BC HpZ+WWC Le PHARE Zebra Abdalla, Banerji, OL & Rashkov 0812.3831

  20. Neutrino mass from MegaZ-LRG Total mass < 0.3 eV (95% CL) Thomas, Abdalla & OL (2009) 0911.5291

  21. The Dark Energy http://www.darkenergysurvey.org

  22. Dark Energy Science Program Four Probes of Dark Energy • Galaxy Clusters • clusters to z>1 • SZ measurements from SPT • Sensitive to growth of structure and geometry • Weak Lensing • Shape measurements of 300 million galaxies • Sensitive to growth of structure and geometry • Large-scale Structure • 300 million galaxies to z = 1 and beyond • Sensitive to geometry • Supernovae • 15 sq deg time-domain survey • ~3000 well-sampled SNe Ia to z ~1 • Sensitive to geometry Plus QSOs, Strong Lensing, Milky Way, Galaxy Evolution

  23. w(z) =w0+wa(1–a) 68% CL DES Forecasts: Power of Multiple Techniques FoM factor 4.6 tigther compared to near term projects

  24. The DES Collaboration an international collaboration of ~100 scientists from ~20 institutions US: Fermilab, UIUC/NCSA, University of Chicago, LBNL, NOAO, University of Michigan, University of Pennsylvania, Argonne National Laboratory, Ohio State University, Santa-Cruz/SLAC Consortium UK Consortium: UCL, Cambridge, Edinburgh, Portsmouth, Sussex, Nottingham Spain Consortium: CIEMAT, IEEC, IFAE Brazil Consortium: Observatorio Nacional, CBPF,Universidade Federal do Rio de Janeiro, Universidade Federal do Rio Grande do Sul CTIO

  25. DES Organization Over 100 scientists from the US, UK, Spain and Brazil 11 Science Working Groups Supernovae B. Nichol J. Marriner Weak Lensing B. Jain S. Bridle Galaxy Clustering E. Gaztanaga W. Percival Photometric Redshifts F. Castander H. Lin Simulations Kravtsov A. Evrard Clusters J. Mohr T. McKay Milky Way B. Santiago B. Yanny QSOs R. McMahon P. Martini Galaxy Evolution R. Wechsler D. Thomas Theory W. Hu J. Weller Strong Lensing E. Buckley-Geer M. Makler

  26. The Dark Energy Survey (DES) • Proposal: • Perform a 5000 sq. deg. survey of the southern galactic cap • Measure dark energy with 4 complementary techniques • New Instrument: • Replace the PF cage with a new 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)

  27. The 5 lenses are now being polished C2 C1 Polishing & coating coordinated by UCL (with 1.7M STFC funding)

  28. DES Collab. Mtg., OSU, Nov. 8, 2008 Huan Lin Image Level Simulations DECam Focal Plane • 62 2kx4k Science CCDs • (520 Mpix) A single simulated DECam pointing (= tile = hex) 1 GB per single 3 deg2 pointing

  29. Neutrino mass from DES:LSS & Planck Input: M =0.24 eV Output: M =0.24 +- 0.12 eV (95% CL) Lahav, Kiakotou, Abdalla & Blake (0910.4714)

  30. Total Neutrino Mass DESvs.KATRIN M< 0.1 eVM < 0.6 eV t

  31. Wide Extragalactic 20,000 deg2 Galactic Plane Deep ~40 deg2 Euclid Imaging Surveys • Wide Survey: Extragalactic sky (20,000 deg2 = 2p sr) • Visible: Galaxy shape measurements to RIZAB ≤ 24.5 (AB, 10σ) at 0.16” FWHM,yielding 30-40 resolved galaxies/amin2, with a median redshift z~ 0.9 • NIR photometry: Y, J, H ≤ 24 (AB, 5σ PS), yielding photo-z’s errors of0.03-0.05(1+z) with ground based complement (PanStarrs-2, DES. etc) • Concurrent with spectroscopic survey • Deep Survey:40 deg2 at ecliptic poles • Monitoring of PSF drift (40 repeats at different orientations over life of mission) • Produces +2 magnitude in depth for both visible and NIR imaging data. • Possible additional Galactic surveys: • Short exposure Galactic plane • High cadence microlensing extra-solar planet surveys • could be easily added within Euclid mission architecture.

  32. Euclid - impact on Cosmology • Euclid Imaging will challenge all sectors of the cosmological model: • Dark Energy: wp and wa with an error of 2% and 13% respectively (no prior) • Dark Matter: test of CDM paradigm, precision of 0.04eV on sum of neutrino masses (with Planck) • Initial Conditions: constrain shape of primordial power spectrum, primordial non-gaussianity • Gravity: test GR by reaching a precision of 2% on the growth exponent  (dlnm/dlnam) • Uncover new physics and Map LSS at 0<z<2: Low redshift counterpart to CMB surveys

  33. What will be the next paradigm shift? • Vacuum energy (cosmological constant)? • Dynamical scalar field? • w=p/ • for cosmological constant: w = -1 • Manifestation of modified gravity? • Inhomogeneous Universe? • What if cosmological constant after all? • Multiverse - Landscape? • The Anthropic Principle?

  34. THE END

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