Jochen Weller Decrypting the Universe Edinburgh, October, 2007 未来 の 暗 黒 エネルギー 実 験 の 相補性

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Complementarity of Future Dark Energy Probes Jiayu Tang, Filipe Abdalla and JW (DETF::UCL)

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 What would we like to learn from a Dark Energy experiment? Possible ‘explanations’ of observed accelerated expansion: 1.extra energy component in the Universe (see Copeland) 2.modification of gravity on large scales (see Maartens) 3.inhomogeneous Universe - acceleration effect of averaging procedure Key Question: Different from cosmological constant? –unique feature of  : energy density constant –test if energy density varies with time (redshift, scale factor) –effectively looking for “w=p/  ”; of course not really physical meaning for 2. and 3.

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Parameterizations of Dark Energy Background evolution  w = w 0  w = w 0 +w 1 z  w = w 0 +  ln(a) (Efstathiou 1999)  w = w 0 +w a (1-a) (Chevalier 2001, Linder 2003)  binned w(z) (‘parameter free’) Perturbations: c s 2, ,...

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Binning of w(z) use 50 (large number) bins z max given by particular survey effectively parameter free continuous binning required for including CMB (Crittenden & Pogosian 2005) Fiducial model: w = -0.9 constant

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Principal Component Analysis Calculate Fisher matrix for leading order approximation of Likelihood Diagonalize Fisher matrix do establish independent modes Decompose w(z) in Eigenmodes Inverse of eigenvalue is measure of uncertainty in Eigenmode (  j = j -1/2 ), Eigenmode reflects redshift sensitivity of survey (Huterer and Starkman 2003; Crittenden & Pogosian 2005) Going beyond DETF figure of merit and pivot redshift

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Analysis with Principal Components Establish leading components via Fisher matrix Estimate coefficients with MCMC or full likelihood (may need to iterate fiducial model) (Huterer and Peiris, 2007) How about priors on Eigenmodes? How to establish number of modes to take along (risk, likelihood ratio, F-test, evidence)?

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Future Observations (very subjective) South Pole Telescope: 1000 element Bolometer Array; 4,000 deg 2 ; 150,250 and 270 GHz; 10m telescope; 1’ beam; deployed begining of PanStarrs: photo-z; z=0-1; >30,000 deg 2 ; 23.8 mag; griz and y filter and wide band (g+r+i); 4 cameras at PS4 on 1.8m mirror (1.4 billion pixels) (see Phleps talk). Dark Energy Survey: Imaging Survey on 4m Blanco; 5,000 deg 2 sky coverage; 24mag in griz+VISTA IR; photo-z; z= (see Lahav talk) WFMOS: Spectrograph on Gemini (Subaru) telescope, limiting m=24, wide survey: 2000 deg 2, z = ; deep survey: 300 deg 2, z = (see Parkinson/Miyazaki talk) DUNE: Satellite; Imaging survey, photo-z; z= , half sky, one wide (r+i+z) band and NIR; mag limit 24.5; ground based complement (see Refregier talk) SNAP: Satellite; 6 optical + 3 NIR filters; z=0-1.7, 300 deg 2 WL

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Supernovae Probes Measure of redshift - distance relation SNAP: 3000 SNe Most weight at redshift z=0.2 (DE domination) Modes above 3rd are very weakly constrained (  1 = 0.14;  2 = 0.30;  3 = 0.55) Mode becomes negative here

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Comparison of SNe probes DES: 1,900 SNe (  1 = 1.26;  2 = 3.46) PanStarrs: 6,000 SNe (  1 = 0.13;  1 = 0.28) SNAP and PanStarrs very similar

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Weak Lensing Probes Probing expansion and growth of structure DES: z max = 2.0;   = 0.34 Leading Principal Components reflect redshift bins Strong constraints at z=0.3 and z=1.0  1 = 0.25;  2 = 2.95;  3 = 3.93

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Comparison of WL probes Use simulated galaxy redshift distributions (DES: Huan Lin, DUNE: Peter Capak) SNAP 2-bins: z max = 3.0;   =0.31 (  1 = 1.67;  2 = 5.91) SNAP 3-bins: (  1 = 0.39;  2 = 2.37) DES 1-bin: (  1 = 50.0;  2 = 78.0) DES 3-bins: (  1 = 0.25;  2 = 2.95) DUNE 1-bin: z max = 3.0;   =0.40 (  1 = 24.9;  2 = 33.7) DUNE 5-bins: (  1 = ;  2 = 0.031)

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Baryon Acoustic Oscillations Measure of angular diameter distance Combination of wide and deep WFMOS survey. k max = 0.15 cut-off Peak constraint above z=0.5!  1 = 0.17;  2 = 0.53;  3 = 0.66

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Sunayev-Zel’dovich Galaxy Cluster Counts Measure of growth and volume z max = 1.5 Peak below z=0.5  1 = 0.39;  2 = 0.96;  3 = 1.55

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Effects of Other Cosmological Parameters Other cosmological parameters (  m, H 0,M,...) Marginalize Fisher matrix over extra parameters and then calculate principal components sign of mode changes above z=0.5 peak of modes shifts to lower redshift so far no priors on w –conservative (-1<w<-1/3) –smoothness

Jochen Weller Decrypting the Universe Edinburgh, October, 2007 Comparing Different Surveys Clearly WL (from DUNE) is best constraint for z<1, while BAO is most promising for larger redshifts, however these are Stage IV (DETF) missions Galaxy cluster number counts not as good as SNe (but are forthcoming data sets) and are at Stage II-III. More to come... (ADEPT, PANSTARRS WL,...)