1. Dark Energy Survey The DES Collaboration Josh Frieman, Ofer Lahav, JW

2. Jochen Weller EDEN in Paris December, 7th-9th The DES Collaboration Fermilab: J. Annis, H. T. Diehl, S. Dodelson, J. Estrada, B. Flaugher, J. Frieman, S. Kent, H. Lin, P. Limon, K. W. Merritt, J. Peoples, V. Scarpine, A. Stebbins, C. Stoughton, D. Tucker, W. Wester University of Illinois at Urbana-Champaign: C. Beldica, R. Brunner, I. Karliner, J. Mohr, R. Plante, P. Ricker, M. Selen, J. Thaler University of Chicago: J. Carlstrom, S. Dodelson, J. Frieman, M. Gladders, W. Hu, S. Kent, A. Kravtsov, E. Sheldon, R. Wechsler Lawrence Berkeley National Lab: G. Aldering, N. Roe, C. Bebek, M. Levi, S. Perlmutter NOAO/CTIO: T. Abbott, C. Miller, C. Smith, N. Suntzeff, A. Walker Institut d'Estudis Espacials de Catalunya: F. Castander, P. Fosalba, E. Gaztañaga, J. Miralda-Escude Institut de Fisica d'Altes Energies: E. Fernández, M. Martínez University College London: O. Lahav, P. Doel, M. Barlow, S. Bridle, S. Viti, S. Warwick, J. Weller University of Cambridge: G. Efstathiou, R. McMahon, W. Sutherland University of Edinburgh: J. Peacock University of Portsmouth: R. Nichol University of Michigan: R. Bernstein, B. Bigelow, M. Campbell, A. Evrard, D. Gerdes, T. McKay, M. Schubnell, G. Tarle, M. Tecchio

3. Jochen Weller EDEN in Paris December, 7th-9th Dark Energy: Stress Energy vs. Modified Gravity Stress-Energy: G  = 8  G [T  (matter) + T  (dark energy)] Gravity: G  + f(g  ) = 8  G T  (matter) Key Experimental Questions: 1.Is DE observationally distinguishable from a cosmological constant, for which T  (vacuum) =  g  /8  G? To decide, measure w: what precision is needed? 2.Can we distinguish between gravity and stress-energy? 3.If w   1, it likely evolves: how well can/must we measure dw/da to make progress in fundamental physics?

4. Jochen Weller EDEN in Paris December, 7th-9th Probing Dark Energy with the Expansion History of the Universe comoving distance standard candles standard rulers volume factor growth of structure depends on H(z) probed with power spectrum

5. Jochen Weller EDEN in Paris December, 7th-9th The Dark Energy Survey  Study Dark Energy using 4 complementary* techniques: Cluster counts & clustering Weak lensing Galaxy angular clustering SNe Ia distances Two multiband surveys: 5000 deg 2 g, r, i, z 40 deg 2 repeat (SNe) Build new 3 deg 2 camera Construction 2005-2009 Survey 2009-2014 (525 nights)  Study Dark Energy using 4 complementary* techniques: Cluster counts & clustering Weak lensing Galaxy angular clustering SNe Ia distances Two multiband surveys: 5000 deg 2 g, r, i, z 40 deg 2 repeat (SNe) Build new 3 deg 2 camera Construction 2005-2009 Survey 2009-2014 (525 nights) Blanco 4-meter at CTIO *in systematics & in cosmological parameter degeneracies *geometric+growth: test Dark Energy vs. Gravity

6. Jochen Weller EDEN in Paris December, 7th-9th The DES Telescope  NOAO/CTIO 4m Blanco telescope 1970 era, equatorial mount An existing, working telescope On-going studies: finite element analysis, laser metrology, PSF pattern modeling  Solid primary mirror 50cm thick Cervit, 15 tons  Mechanical mirror support system radial: purely mechanical axial: 3 load cell hard points + controllable support cells  Primary cage DES will replace entire cage will have radial (alignment) movement  Cerro Tololo site delivers median 0.65” Sept-Feb current Mosaic II+telescope delivers median 0.9” Sept-Feb  NOAO/CTIO 4m Blanco telescope 1970 era, equatorial mount An existing, working telescope On-going studies: finite element analysis, laser metrology, PSF pattern modeling  Solid primary mirror 50cm thick Cervit, 15 tons  Mechanical mirror support system radial: purely mechanical axial: 3 load cell hard points + controllable support cells  Primary cage DES will replace entire cage will have radial (alignment) movement  Cerro Tololo site delivers median 0.65” Sept-Feb current Mosaic II+telescope delivers median 0.9” Sept-Feb 24 Radial Supports 3 Hard Points 33 Pressure Pads Abbott, Walker, Peoples, Bernstein...

7. Jochen Weller EDEN in Paris December, 7th-9th Dark Energy Survey Instrument 3.5 meters Camera Filters Optical Lenses Scroll Shutter 1.5 meters New Prime Focus Cage, Camera, and Corrector for the Blanco 4m Telescope 500 Megapixels, 0.27”/pixel Project cost: ~20M$ (incl. labor)

8. Jochen Weller EDEN in Paris December, 7th-9th Photometric Redshifts Measure relative flux in four filters griz: track the 4000 A break Estimate individual galaxy redshifts with accuracy  (z) ~ 0.1 (~0.02 for clusters) This is sufficient for Dark Energy probes (biases ?) Note: good detector response in z band filter needed to reach z~1.3

9. Seeing Issues  ‘Seeing’ is due to intrinsic PSF, telescope flexure, atmospheric turbulence the dome,…  Recent records for medians  @ CTIO site 0.67 arcsec during Sep-Feb; @ Blanco Mosaic II 0.9 arcsec Efforts to reduce it!  ‘Seeing’ is due to intrinsic PSF, telescope flexure, atmospheric turbulence the dome,…  Recent records for medians  @ CTIO site 0.67 arcsec during Sep-Feb; @ Blanco Mosaic II 0.9 arcsec Efforts to reduce it! * Seeing affects the number of galaxy images ‘usable’ for lensing

10. Jochen Weller EDEN in Paris December, 7th-9th Improved Optical Image Quality of DECAM vs. Mosaic II Focus and wavefront sensor chips: actively correct focus and collimation New optical corrector designed to deliver good image quality over FOV and won’t be cracked Reduce power dissipation in vicinity of camera Precision focal plane alignment Model and track PSF vs. focal plane position, zenith angle (refraction), defocus, decollimation Typical object will be imaged ~24 times in riz and enough survey time to use best conditions for WL Gladders, Kent

11. Jochen Weller EDEN in Paris December, 7th-9th DES Area and Depth: Synergy with South Pole Telescope  South Pole Telescope: 4000 sq. deg. survey Detect ~20,000 clusters through Sunyaev-Zel’dovich effect Dark Energy Survey: measure photometric redshifts for these clusters to z ~ 1-1.3: griz ~ 24 Galactic Dust Map

12. Jochen Weller EDEN in Paris December, 7th-9th 10m South Pole Telescope (SPT) and 1000 Element Bolometer Array Low noise, precision telescope 1.0 arcminute 3 levels of shielding - ~1 m radius on primary - inner moving shields - outer fixed shields SZE and CMB Anisotropy - 4000 sq deg SZE survey - deep CMB anisotropy fields - deep CMB Polarization fields 1000 Element Bolometer Array - 3 to 4 interchangeable bands (90) 150, 250 & 270 GHz People Carlstrom (UC) Holzapfel (UCB) Lee (UCB,LBNL) Leitch (UC) Meyer (UC) Mohr (U Illinois) Padin (UC) Pryke (UC) Ruhl (CWRU) Spieler (LBNL) Stark (CfA)

13. Jochen Weller EDEN in Paris December, 7th-9th Cluster Redshift Distribution and Dark Energy Raising w at fixed  DE :  decreases volume surveyed Raising w at fixed  DE :  decreases volume surveyed Volume effect Growth effect  decreases growth rate of density perturbations Constraints: Mohr

14. Jochen Weller EDEN in Paris December, 7th-9th Cosmology with Clusters  Requirements 1.Quantitative understanding of the formation of dark matter halos in an expanding universe 2.Clean way of selecting a large number of massive dark matter halos (galaxy clusters) over a range of redshifts 3.Redshift estimates for each cluster (photo-z’s adequate) 4.Observables that can be used as mass estimates at all redshifts  Requirements 1.Quantitative understanding of the formation of dark matter halos in an expanding universe 2.Clean way of selecting a large number of massive dark matter halos (galaxy clusters) over a range of redshifts 3.Redshift estimates for each cluster (photo-z’s adequate) 4.Observables that can be used as mass estimates at all redshifts Sensitivity to Mass Jenkins, et al

15. SZE vs. Cluster Mass: Simulations Motl, et al Integrated SZE flux decrement insensitive to gas dynamics in the cluster core

16. Jochen Weller EDEN in Paris December, 7th-9th Flux decrement vs. mass and redshift Nagai - astro-ph/0512208 11 clusters; ART (Kravtsov) blue: star formation, metal enrichment and thermal feedback due to the supernovae type II and type Ia, self-consistent advection of metals, metallicity dependent radiative cooling and UV heating due to cosmological ionizing background shifted for clarity

17. Jochen Weller EDEN in Paris December, 7th-9th DES Cluster Photometric Redshift Simulations  (z)~0.02 to z=1.3

18. Jochen Weller EDEN in Paris December, 7th-9th Lima and Hu Hu wawa 1 Self-calibration with Clustering See also Battye and Weller, Majumdar & Mohr

19. Jochen Weller EDEN in Paris December, 7th-9th Mapping the Mass in a Cluster of Galaxies via Weak Gravitational Lensing (no arcs) Abell 3667 CTIO 4-m image Joffre, etal

20. Jochen Weller EDEN in Paris December, 7th-9th Calibration of the Mass - Temperature Relation with Weak Lensing (Dodelson & Weller, in preparation)

21. Jochen Weller EDEN in Paris December, 7th-9th Observer Overdensities Background sources Statistical measure of shear pattern, ~1% distortion. Radial distances, r(z), depends on geometry of Universe. Dark Matter pattern & growth depends on cosmological parameters.

22. Lensing Tomography Shear at z 1 and z 2 given by integral of growth function & distances over lensing mass distribution. z1z1 z2z2 z l1 lensing mass z l2

23. Jochen Weller EDEN in Paris December, 7th-9th DES Weak Lensing Tomography Measure shapes for ~300 million source galaxies with  z  = 0.7 Shear-shear & galaxy-shear correlations probe distances & growth rate of perturbations Requirements: Sky area, depth, photo-z’s, image quality & stability Measure shapes for ~300 million source galaxies with  z  = 0.7 Shear-shear & galaxy-shear correlations probe distances & growth rate of perturbations Requirements: Sky area, depth, photo-z’s, image quality & stability Huterer

24. Jochen Weller EDEN in Paris December, 7th-9th DES griz filters 10  Limiting Magnitudes g24.6 r24.1 i24.0 z23.9 +2% photometric calibration error added in quadrature  (z)~0.1 to z~1.3 Galaxy Photo-z Simulations Cunha, Lima, Oyaizu, Lin, Frieman, Collister, Lahav

25. Jochen Weller EDEN in Paris December, 7th-9th DES + VISTA griz+YJHKs filters 10  Limiting Magnitudes Y22.45 J22.15 H21.65 Ks21.15 (~15 min exposures)  (z) ~ 0.07 Galaxy Photo-z Simulations

26. Jochen Weller EDEN in Paris December, 7th-9th Ma, Hu, & Huterer (2005) Impact of Uncertainty in Photo-z Error Distribution on w Spectroscopic `Training Set’ needed to measure photo-z error distribution to required accuracy: N ~ 50,000 - 100,000

27. Jochen Weller EDEN in Paris December, 7th-9th DES Supernovae  Repeat observations of 40 deg 2, 10% of survey time ~1900 well-measured riz SN Ia lightcurves, 0.25 < z < 0.75  Repeat observations of 40 deg 2, 10% of survey time ~1900 well-measured riz SN Ia lightcurves, 0.25 < z < 0.75 SN constraints `orthogonal’ to the other methods  z=0.1 bins assumed Huterer

28. Jochen Weller EDEN in Paris December, 7th-9th Forecast DES Constraints on w Key Priors:  Constant w, spatially flat, power-law, adiabatic, Gaussian initial fluctuations,w/ CDM, massless neutrinos  Marginalize over 3-parameter SZ(M) with no scatter  5 halo model bias parameters per photo-z bin  WL: l <1000  SN: sys. error floor,  (m)=0.25, 300 low-z SNe to anchor Hubble diagram Key Priors:  Constant w, spatially flat, power-law, adiabatic, Gaussian initial fluctuations,w/ CDM, massless neutrinos  Marginalize over 3-parameter SZ(M) with no scatter  5 halo model bias parameters per photo-z bin  WL: l <1000  SN: sys. error floor,  (m)=0.25, 300 low-z SNe to anchor Hubble diagram Method/priorsUniformWMAPPlanck Cluster abundance: 5  SZ clusters w/ WL mass calibration (no clustering information) 0.090.080.03 shear-shear (SS) galaxy-shear (GS) + galaxy- galaxy(GG) SS+GS+GG SS+bispectrum 0.15 0.08 0.03 0.07 0.05 0.03 0.05 0.02 0.03 Galaxy angular clustering0.360.200.11 Supernovae Ia0.340.150.04 Flaugher, Walker, Abbott...

29. Jochen Weller EDEN in Paris December, 7th-9th DES+SPT next step in dark energy measurements: Will measure constant w to ~ 0.02–0.1 statistical accuracy* using multiple complementary probes, and begin to constrain dw/dz Survey strategy delivers substantial DE science after 2 years Scientific and technical precursor to the more ambitious and costly Dark Energy projects to follow: LST and JDEM DES in unique position to synergize with SPT on this timescale *accuracy on each probe separately, with Planck priors Dark Energy: 2009-2014