Cosmology Surveys a nonWHT talk Dark Energy science

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Cosmology Surveys (a non-WHT talk) - Dark Energy science and beyond - Imaging surveys

Cosmology Surveys (a non-WHT talk) - Dark Energy science and beyond - Imaging surveys - Spectroscopic surveys Ofer Lahav University College London

“Evidence” for Dark Energy Observational data • • • Type Ia Supernovae Galaxy Clusters

“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: H 2(z) = H 20 [ M (1+z) 3 + DE (1+z) 3 (1+w) ] (flat)

Dark Energy Pre-SNIa • Peebles (1984) advocated Lambda • APM result for low matter

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… Calder & OL, Physics World, Jan 2010

What will be the next paradigm shift? • Vacuum energy (cosmological constant)? • Dynamical

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?

Standard rulers

Standard rulers

Baryonic Acoustic Oscillations Comving distance SDSS Luminous Red Galaxies Density fluctuations z=0. 5 Harmonic

Baryonic Acoustic Oscillations Comving distance SDSS Luminous Red Galaxies Density fluctuations z=0. 5 Harmonic l CMB WMAP Temperature fluctuations z=1000

Probing the Geometry of the Universe with Supernovae Ia ‘Union’ SN Ia sample (Kowalski

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

In 3 Dimensions Massey et al. 2007

In 3 Dimensions Massey et al. 2007

Galaxy Surveys 2010 -2020 Photometric surveys: DES, Pan-STARRS, HSC, Skymapper, PAU, LSST, Euclid (EIC),

Galaxy Surveys 2010 -2020 Photometric surveys: DES, Pan-STARRS, HSC, Skymapper, PAU, LSST, Euclid (EIC), JDEM(SNAP-like), … Spetroscopic surveys: Wiggle. Z, BOSS, Big. BOSS, hetdex, WFMOS/Sumire, Euclid (NIS) JDEM (Adept-like), SKA, …

Photometric redshifts • Probe strong spectral features (e. g. 4000 break) • Template vs.

Photometric redshifts • Probe strong spectral features (e. g. 4000 break) • Template vs. Training methods z=0. 1 z=3. 7

Mega. Z-LRG Photoz scatter of 0. 04 • Input: 10, 000 galaxies with spectra

Mega. Z-LRG Photoz scatter of 0. 04 • Input: 10, 000 galaxies with spectra • Train a neural network • ANNz, Collister & Lahav 2004 • Output: 1, 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!

Neutrino mass from Mega. Z-LRG Total mass < 0. 3 e. V (95% CL)

Neutrino mass from Mega. Z-LRG Total mass < 0. 3 e. V (95% CL) Thomas, Abdalla & OL (2009) 0911. 5291

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

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

The DES Collaboration an international collaboration of ~100 scientists from ~20 institutions US: Fermilab,

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: CTIO Observatorio Nacional, CBPF, Universidade Federal do Rio de Janeiro, Universidade Federal do Rio Grande do Sul

The Dark Energy Survey (DES) • Proposal: – Perform a 5000 sq. deg. survey

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 4 m Telescope at the Cerro Tololo Inter-American Observatory (CTIO)

The 5 lenses are now being polished C 2 C 1 Polishing & coating

The 5 lenses are now being polished C 2 C 1 Polishing & coating coordinated by UCL (with 1. 7 M STFC funding)

Euclid Imaging Surveys Wide Survey: Extragalactic sky (20, 000 deg 2 = 2 p

Euclid Imaging Surveys Wide Survey: Extragalactic sky (20, 000 deg 2 = 2 p sr) • Visible: Galaxy shape measurements to RIZAB ≤ 24. 5 (AB, 10σ) at 0. 16” FWHM, yielding 30 -40 resolved galaxies/amin 2, with a median redshift z~ 0. 9 • NIR photometry: Y, J, H ≤ 24 (AB, 5σ PS), yielding photo-z’s errors of 0. 03 -0. 05(1+z) with ground based complement (Pan. Starrs-2, DES. etc) • Concurrent with spectroscopic survey Deep Survey: 40 deg 2 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. Wide Extragalactic 20, 000 deg 2 Galactic Plane Deep ~40 deg 2

Spectroscopic Surveys SDSS 2 MRS Cf. A 2 d. FGRS

Spectroscopic Surveys SDSS 2 MRS Cf. A 2 d. FGRS

SUBARU: the ups and downs of WFMOS and the hopes for SUMIRE

SUBARU: the ups and downs of WFMOS and the hopes for SUMIRE

Redshift Distortion as a test of Modified Gravity Guzzo et al. 2008

Redshift Distortion as a test of Modified Gravity Guzzo et al. 2008

Big. BOSS: The Ground-Based Stage IV BAO Experiment A new 5000 -fiber R=5000 spectrograph

Big. BOSS: The Ground-Based Stage IV BAO Experiment A new 5000 -fiber R=5000 spectrograph covering a 3 degree diameter field will measure BAO and redshift space distortions in the distribution of galaxies and hydrogen gas spanning redshifts from 0. 2 < z < 3. 5. The Dark Energy Task Force figure of merit (DETF Fo. M) for this experiment is expected to be equal to that of a JDEM mission for BAO with the lower risk and cost typical of a ground-based experiment • http: //bigboss. lbl. gov/

Cosmology Surveys summary * Goal: Dark Energy parameters to a few % level •

Cosmology Surveys summary * Goal: Dark Energy parameters to a few % level • Both imaging and spectroscopy surveys are essential • Is a BAO survey with a 4 m feasible? • Non-DE science with DE surveys (e. g. Neutrino mass, galaxy evolution, MW structure, QSOs)

THE END

THE END

Planned photometric and spectroscopic surveys

Planned photometric and spectroscopic surveys

The Dark Energy problem: 10, 90 or 320 years old? The weak field limit

The Dark Energy problem: 10, 90 or 320 years old? The weak field limit of GR: F = -GM/r 2 + /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)

Dark Energy Science Program Four Probes of Dark Energy • Galaxy Clusters • clusters

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

DES Forecasts: Power of Multiple Techniques w(z) =w 0+wa(1–a) 68% CL Fo. M factor

DES Forecasts: Power of Multiple Techniques w(z) =w 0+wa(1–a) 68% CL Fo. M factor 4. 6 tigther compared to near term projects

The Chequered History of the Cosmological Constant * The old CC problem: Theory exceeds

The Chequered History of the Cosmological 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?

Photo-z –Dark Energy cross talk • Approximately, for a photo-z slice: ( w/ w)

Photo-z –Dark Energy cross talk • Approximately, for a photo-z slice: ( w/ w) = 5 ( z/ z) = 5 ( z/z) Ns-1/2 => the target accuracy in w and photo-z scatter z dictate the number of required spectroscopic redshifts Ns =105 -106

Euclid - impact on Cosmology Δwp Current+WMAP ΔWa ΔΩm ΔΩΛ ΔΩb Δσ8 Δns Δh

Euclid - impact on Cosmology Δwp Current+WMAP ΔWa ΔΩm ΔΩΛ ΔΩb Δσ8 Δns Δh DE Fo. M 0. 13 - 0. 015 0. 0015 0. 026 0. 013 ~10 - - 0. 008 - 0. 0007 0. 05 0. 007 - 0. 03 0. 17 0. 006 0. 04 0. 012 0. 013 0. 02 0. 1 180 Imaging Probes 0. 018 0. 15 0. 004 0. 02 0. 007 0. 0009 0. 014 0. 07 400 Euclid 0. 016 0. 13 0. 003 0. 012 0. 005 0. 003 0. 006 0. 020 500 0. 01 0. 066 0. 0008 0. 003 0. 0004 0. 0015 0. 003 0. 002 1500 13 >15 13 5 4 17 4 7 150 Planck Weak Lensing Euclid +Planck Factor Gain 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. 04 e. V 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