Understanding the Properties of Dark Energy in the Universe Dragan Huterer Case Western Reserve University Understanding the Properties of Dark Energy in the Universe p.1/37
The Cosmic Food Pyramid?? Radiation ( ) Luminous Matter ( ) Baryonic Matter ( ) Dark Matter ( ) Dark Energy ( ) Understanding the Properties of Dark Energy in the Universe p.2/37
Type Ia Supernovae -20 B Band -19 as measured M B 5 log(h/65) -18-17 -16-15 -20 0 20 40 60 days -20 Calan/Tololo SNe Ia -19 light-curve timescale stretch-factor corrected M B 5 log(h/65) -18-17 -16-15 -20 0 20 40 60 days Kim, et al. (1997) Understanding the Properties of Dark Energy in the Universe p.3/37
Discovering SNe Ia Supernova 1998ba Supernova Cosmology Project (Perlmutter, et al., 1998) (as seen from Hubble Space Telescope) 3 Weeks Before Supernova Discovery (as seen from telescopes on Earth) Difference Understanding the Properties of Dark Energy in the Universe p.4/37
=0.0 =1.0, &! )( "$% "$#! + * Understanding the Properties of Dark Energy in the Universe p.5/37 Recent Supernova data High-Z SN Search Team Supernova Cosmology Project =0.7 =0.3, m-m (mag) =0.0 =0.3, (m-m) (mag) 0.01 0.10 1.00 z
) & & ) & & & & Parameterizing Dark Energy %, & % " % % (flat) ( " % ( " # ( % % # Understanding the Properties of Dark Energy in the Universe p.6/37
) & & ) & & & & Parameterizing Dark Energy %, & % " % % (flat) ( " % ( " # ( % % # may be varying: ( ( * Understanding the Properties of Dark Energy in the Universe p.6/37
Current Supernova Constraints Understanding the Properties of Dark Energy in the Universe p.7/37
& & Fine-Tuning Problems I: Why Now? DE is important only at, since % # " % " # ( and ) 10 20 10 0 ρ RAD Λ dominates ρ (GeV 4 ) 10-20 ρ M 10-40 ρ Λ 10-60 10 15 10 10 1+z 10 5 10 0 Understanding the Properties of Dark Energy in the Universe p.8/37
)( )( Fine-Tuning Problems II: Why so small? Refers to the vacuum energy,. (recall ) 50 120 orders of magnitude discrepancy! Understanding the Properties of Dark Energy in the Universe p.9/37
A candidate: Quintessence 1.2 V Equation-of-state ( w Q ) 0.8 0.4 0.0-0.4-0.8 KE dominates Q frozen Q joins tracker sol. -1.2 10 12 z+1 10 10 10 8 10 6 10 4 10 2 10 0 10-10 ρ (GeV 4 ) 10-20 10-30 φ 10-40 Peebles & Ratra 1987, Caldwell, Dave & Steinhardt 1998 10-50 10 12 z+1 10 10 10 8 10 6 10 4 10 2 10 0 Understanding the Properties of Dark Energy in the Universe p.10/37
Classical Tests 4.0 3.0 2.0 r(z) w=-1.0 w=-0.4 dv/dωdz0.4 0.2-1.0-0.8-0.6 w=-0.4 1.0 -dr/dw 0.0 0.0 0.1 1.0 10.0 100.0 1000.0 z 1 0 0 1 2 3 z δ(z)/δ(today) 0.1 w= 1/3 w= 1 10.0 z 1.0 0.1 Understanding the Properties of Dark Energy in the Universe p.11/37
& Wish List, " % Goals: Measure & % equivalently, Measure Measure any clustering of DE Difficulties: DE may cluster at scales Understanding the Properties of Dark Energy in the Universe p.12/37
Cosmological Tests of Dark Energy SNAP CURRENT SN 1a Matter density Vacuum density constant Tegmark 2001 Understanding the Properties of Dark Energy in the Universe p.13/37
Weak Gravitational Lensing Understanding the Properties of Dark Energy in the Universe p.14/37
Current Data and Constraints 1.5 σ 8 1 0.5 0 0.5 1 Ω M Refregier 2003, Bacon et al. 2003 Understanding the Properties of Dark Energy in the Universe p.15/37
Weak Lensing and DE 10 2 10 4 Ω X =0.70, w= 1.0 Ω X =0.70, w= 0.5 Ω X =0.65, w= 1.0 l(l+1)p l κ/(2π) 10 6 10 8 linear 10 10 1 10 100 1000 10000 l Hu 1999, Huterer 2002, Refregier et al. 2003 Understanding the Properties of Dark Energy in the Universe p.16/37
Weak Lensing and DE 0.8 0.6 n(z) 0.4 l(l+1)p l κ/(2π) 10 2 10 4 10 6 10 8 Ω X =0.70, w= 1.0 Ω X =0.70, w= 0.5 Ω X =0.65, w= 1.0 linear 0.2 0 0.0 0.2 0.4 0 1 2 3 4 5 z 1 redshift bin 2 bins 10 bins w 0.6 10 10 1 10 100 1000 10000 l 0.8 Hu 1999, Huterer 2002, Refregier et al. 2003 1.0 0 0.2 0.4 0.6 0.8 1 Ω M Understanding the Properties of Dark Energy in the Universe p.16/37
Deeper and Wider 0.05 0.10 0.04 σ(w) 0.08 σ(w) 0.03 0.06 0.02 σ(ω X ) 0.04 σ(ω X ) 0.01 0.02 0.00 25 26 27 28 29 depth (R band mag) 0.00 10 100 1000 10000 sky coverage (deg 2 ) Huterer 2002 Understanding the Properties of Dark Energy in the Universe p.17/37
Number Counts dn/dz (4000 deg 2 ) 10 5 10 4 10 3 10 2 w=-0.8 Ω M =1, Ω DE =0 Ω M =0.3, Ω DE =0.7, w=-1 0 0.5 1 1.5 2 z Understanding the Properties of Dark Energy in the Universe p.18/37
Number Counts Count clusters using X-ray, SZ, weak lensing... Mass-observable relation Haiman, Mohr & Holder 2001, Majumdar & Mohr 2003 Understanding the Properties of Dark Energy in the Universe p.19/37
Cosmic Microwave Background Anisotropies Bennett et al. 2003 (WMAP collaboration) Understanding the Properties of Dark Energy in the Universe p.20/37
CMB Sensitivity to Dark Energy Peak locations are sensitive to dark energy (but not much): 7000 6000 w = -1.0 w = -0.5 l(l+1)c l / (2π) (µk 2 ) 5000 4000 3000 2000 1000 Same as measurement of with fixed End up constraining: (Planck: to %) 0 1 10 100 1000 10000 l Huterer & Turner 2001, Frieman et al. 2003 Understanding the Properties of Dark Energy in the Universe p.21/37
SNe plus CMB constant σ w 0.6 0.5 0.4 0.3 SNe SNe + σ ΩM = 0.03 SNe + σ ΩM = 0.01 SNe + Planck SNe + Planck + σ ΩM = 0.01 σ dw/dz 1.4 1.2 1 0.8 0.6 SNe SNe + σ ΩM = 0.03 SNe + σ ΩM = 0.01 SNe + Planck SNe + Planck + σ ΩM = 0.01 0.2 0.4 0.1 0.2 0 0.5 1 1.5 2 2.5 z MAX 0 0.5 1 1.5 2 z MAX Frieman, Huterer, Linder & Turner 2003 Understanding the Properties of Dark Energy in the Universe p.22/37
CMB-LSS cross-correlation Understanding the Properties of Dark Energy in the Universe p.23/37
Understanding the Properties of Dark Energy in the Universe p.23/37 CMB-LSS cross-correlation Ω Λ = 0.0 Ω Λ = 0.5 Ω Λ = 0.8 150 100 50 Number of Realizations 0 0.1 0.0 0.1 0.2 0.3 XT /σ X σ T Boughn, Crittenden & Turok 1997
CMB-LSS cross-correlation 2 1.5 z ~ 0.57 z ~ 0.49 1 Number of Realizations 150 100 50 Ω Λ = 0.0 Ω Λ = 0.5 Ω Λ = 0.8 w gt (θ) [µk] 0.5 0-0.5 1.5 z ~ 0.43 1 0.5 0-0.5 z ~ 0.35 0 0.1 0.0 0.1 0.2 0.3 XT /σ X σ T -1 1 10 θ (degrees) 1 10 Boughn, Crittenden & Turok 1997, Scranton et al. 2003 Understanding the Properties of Dark Energy in the Universe p.23/37
Strong Gravitational Lensing Understanding the Properties of Dark Energy in the Universe p.24/37
Strong Lensing Statistics Required input: Cosmology (, Luminosity function (galaxies) or mass function (all halos), ) τ 10-2 10-3 10-4 Density profile of lenses e.g. SIS: or generalized NFW: Magnification bias 10-5 10-6 1 1.2 1.4 1.6 1.8 2 β Kochanek 1993, 1996, Cooray & Huterer 1999, Chae 2003, Davis, Huterer & Krauss 2003, Kuhlen, Keeton & Madau 2003 Understanding the Properties of Dark Energy in the Universe p.25/37
Strong Lensing Statistics Required input: 10 14 Cosmology (,, ) Luminosity function (galaxies) or mass function (all halos) Density profile of lenses e.g. SIS: or generalized NFW: Magnification bias M c / (h -1 M sun ) 10 13 10 12 68% CL 95% CL 0.5 0.75 1 1.25 1.5 1.75 2 β Huterer & Ma 2003 Understanding the Properties of Dark Energy in the Universe p.25/37
Beyond 1.0 ( 0.5 w 0.0-0.5-1.0-1 -0.9-0.8-0.7-0.6-0.5 w 0 Understanding the Properties of Dark Energy in the Universe p.26/37
Beyond 1.0 ( 0.5 w 0.0-0.5-1.0-1 -0.9-0.8-0.7-0.6-0.5 w 0 0.5 50 1 3 49 Principal Components of e i (z) 0 4 Huterer & Starkman 2003 2-0.5 0 0.5 1 1.5 z Understanding the Properties of Dark Energy in the Universe p.26/37
Reconstruction of ( "$# ( ( ( "$# 0.0 0.2 w(z) 0.4 0.6 0.8 1.0 0 0.2 0.4 0.6 0.8 1 z Huterer and Turner 1999; Chiba and Nakamura 1999, Weller & Albrecht 2002 Understanding the Properties of Dark Energy in the Universe p.27/37
Requirements SCIENCE Measure Ω and Λ M Measure w and w(z) STATISTICAL REQUIREMENTS Sufficient (~2000) numbers of SNe Ia...distributed in redshift...out to z < 1.7 SYSTEMATICS REQUIREMENTS Identified & proposed systematics: Measurements to eliminate / bound each one to +/-0.02mag DATA SET REQUIREMENTS Discoveries 3.8 mag before max. Spectroscopy with S/N=10 at 15 Å bins. Near-IR spectroscopy to 1.7 µm. SATELLITE / INSTRUMENTATION REQUIREMENTS ~2-meter mirror 1-square degree imager 3-channel spectrograph (0.3 µm to 1.7 µm) Derived requirements: High Earth orbit ~5 Mb/sec bandwidth Understanding the Properties of Dark Energy in the Universe p.28/37
SuperNova/Acceleration Probe Understanding the Properties of Dark Energy in the Universe p.29/37
Understanding the Properties of Dark Energy in the Universe p.30/37
Mirror and Focal Plane Understanding the Properties of Dark Energy in the Universe p.31/37
SNAP SuperNova Acceleration Probe ~2500 SNe Ia Understanding the Properties of Dark Energy in the Universe p.32/37
SNAP predicted constraints 3 No Big Bang Dark Energy Unknown Component,Ωu, of Energy Density 2 Supernovae 0.0 Supernova Cosmology Project Perlmutter et al. (1998) vacuum energy density (cosmological constant) 1 0-1 Clusters Maxima SNAP Target Statistical Uncertainty CMB Boomerang open expands forever recollapses eventually flat closed equation of state w = p u / ρ u 0.2 0.4 0.6 0.8 Flat Universe Constant w 99% 95% 90% 68% network of cosmic strings w = 1/3 range of "Quintessence" models cosmological constant w = 1 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Ω Μ = 1 Ωu 0 1 2 3 mass density SNAP Satellite Target Statistical Uncertainty Understanding the Properties of Dark Energy in the Universe p.33/37
Weak Lensing with SNAP -0.5-0.6 0.6 0.4 WL (PS) WL (PS+BS) SNe w -0.7-0.8-0.9 SNe + WL (PS+BS) SNe WL (PS) WL (PS+BS) dw/dz 0.2 0-0.2-0.4 SNe + WL (PS+BS) -1 0 0.1 0.2 0.3 0.4 0.5 Ω M -0.6-1.2-1.1-1 -0.9-0.8 w 0 Understanding the Properties of Dark Energy in the Universe p.34/37
Understanding the Properties of Dark Energy in the Universe p.35/37
NASA-DOE Joint Dark Energy Mission Paul Hertz / NASA Robin Staffin / DOE Endorsed by Raymond L. Orbach Edward J. Weiler Director of the Office of Science Associate Administrator for Space Science Department of Energy NASA September 24, 2003 September 25, 2003 Understanding the Properties of Dark Energy in the Universe p.36/37 1
Conclusions Dark energy makes up of energy density in the universe. It is smooth and has negative pressure. We describe it via and. It affects cosmology by modifying the expansion rate at recent times ( ). SNe Ia, weak lensing and number counts are most promising probes; variety of other methods can help. Bright prospects with future wide-field surveys (SNAP, LSST, SPT,...) But to understand DE, major insights will be needed from theorists. This will be especially hard if! Understanding the Properties of Dark Energy in the Universe p.37/37