LSSTJDEMEuclidBigBOSS南极 KDUST

粒子物理宇宙学德州学院 5/28/10

“The acceleration of the Universe is, along with dark matter, the observedphenomenon that most directly demonstrates that our theories of fundamental particles and gravity are either incorrect or incomplete. Most experts believe that nothing short of a revolution in our understanding of fundamental physics will be required to achieve a full understanding of the cosmic acceleration.” – the Dark Energy Task Force, a joint committee to advise DoE, NASA, & NSF on futuredark energy research.

HEPAP

NRC

NSTC

WIMP? (SUSY: neutralino? gravitino?)Axion?

宇宙学常数 ? Quintessence? Modified Gravity?Back reaction? Brane world? Landscape?

TRgRG 821

American Association for the Advancement of Science Top 125 Questions in all of science

Question #1: What is the universe made of?

…at the moment, the nature of dark energy is arguably the murkiest question in physics--and the one that, when answered, may shed the most light.

德州学院 5/28/10 粒子物理宇宙学

• Brookhaven National Laboratory • California Institute of Technology • Carnegie Mellon University• Chile • Columbia University• Cornell University • Drexel University• Google Inc. • Harvard-Smithsonian Center for

Astrophysics • IN2P3 Labs France• Johns Hopkins University • Kavli Institute for Particle Astrophysics and

Cosmology at Stanford University • Las Cumbres Observatory Global Telescope

Network, Inc. • Lawrence Livermore National Laboratory • Los Alamos National Laboratory

• National Optical Astronomy Observatory• Princeton University • Purdue University • Research Corporation for Science Advancement • Rutgers University• Space Telescope Science Institute• SLAC National Accelerator Laboratory • The Pennsylvania State University • The University of Arizona • University of California, Davis • University of California, Irvine • University of Illinois at Urbana-Champaign• University of Pennsylvania • University of Pittsburgh • University of Washington• Vanderbilt University

LSST

德州学院 5/28/10 粒子物理宇宙学

Riess et al. (1998)

Perlmutter et al. (1999)

The accelerated expansion is an interpretation of the fainter-than-expected supernova apparent magnitudes within the Friedmann-Lemaître-Robertson-Walker framework, and dark energy is a further interpretation of the accelerated expansion.

德州学院 5/28/10 粒子物理宇宙学

XXMMMM

z

z

XKM

pGH

dzzH

czD

zdz

zwzzHzH

342

1

13exp11

0com

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2320

2

It will be harder to distinguish dark energy from modified gravity, if more degrees of freedom are allowed. See, e.g., discussions about generic modified gravity and dark energy with entropy and shear stress perturbations in Bertschinger & Zukin (0801.2431).

Clustering

Well motivated models are needed.

德州学院 5/28/10

Furthermore, the potential fluctuation and curvature fluctuation can differ, leading to inconsistency between lensing and dynamical mass.

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Probe Measurements Remarks

Supernovae DL(z) Presently most powerful

Clusters DA(z), H(z), & G(z) Large systematic errors, need to understand nonlinear astrophysics (e.g., mass—observable relation, mass function, both mean & scatter, …)

BAO DA(z) & H(z) Emerging, less affected by astrophysical uncertainties, less powerful

WL DA(z) & G(z) Emerging, potentially powerful, limited by systematic errors

CMB DLSS & Late ISW Relatively weak constraints

Dark Energy Task Force report(Albrecht et al., astro-ph/0609591)

德州学院 5/28/10 粒子物理宇宙学

德州学院 5/28/10 粒子物理宇宙学

德州学院 5/28/10 粒子物理宇宙学

Dark energy equation of state:w = w0 + wa (1 - a)

SN constraints on w0 & wa depends on the prior on the mean curvature of the universe, because the sensitivity of the luminosity distance to curvature is somewhat degenerate with the sensitivity to wa.

Zhan (2006)

Linder (2005)

SN measures relative luminosity distance:

0

000

10~

,...,,,,1

pc10/log5

H

czzzD

zwwE

zd

H

czD

zDMm

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z

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德州学院 5/28/10

SN absolute magnitude is assumed to evolves as e1 z + e2 z2.

In the left figure, SNAP does not include ground SNe, but does include Planck priors. The prior on e1 and e2 is 0, 0.02, 0.08, and none from inside out.

One cannot achieve (e1) = (e2) = 0.015 (as assumed in the Dark Energy Task Force report) by a joint parameter fitting. Such priors must come from direct observations.

SNAP

iii

iLi

nzeze

zDMm

2

21

pc10/log5

粒子物理宇宙学

DLS survey

CMB temp. fluctuations (WMAP)

Imprints on the matter power spectrum (White 2005)

RS~150 Mpc Angular diameter distance

RS = DA

(Sound horizon at recombination)

Galaxy angular power spectrum

BAOs in multipole space

德州学院 5/28/10 粒子物理宇宙学

= cz /H

Redshift Distortion growth rate testing gravity

德州学院 5/28/10

From Daniel Eisenstein

Curvature perturbations pressure imbalance in photon—baryon fluid sound waves travel at speed ~ c /√3 before recombination and ~ 0 thereafter comoving sound horizon (RS ~ 150 Mpc) freezes excess correlation of density fluctuations at 150 Mpc excess correlation of galaxies at 150 Mpc.

粒子物理宇宙学

WMAP media @ map.gsfc.nasa.gov

德州学院 5/28/10 粒子物理宇宙学

x

g(x)

g(x+x)

Deep Lens Survey, Tyson & Wittman

xkP

x

nn

gg

ggg

FT

1/

xxxx

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Correlation Function

Power Spectrum

SDSS LRGs Eisenstein et al (2005)

Baryon Acoustic Oscillations

Angular PSZhan (2006)

Baryon Acoustic Oscillations in multipole space

德州学院 5/28/10 粒子物理宇宙学

DLS

DS

= 4GM/bc2

b

DLS

DS4GM/bc2

sheared image

shear

Gravity & Cosmology change the growth of mass structure

Cosmology changes geometric distance factors德州学院 5/28/10 粒子物理宇宙学

德州学院 5/28/10 粒子物理宇宙学

The shear correlation originates from correlation of the foreground mass. Note: the cosmic shear, i.e., weak lensing signal, is much weaker!

德州学院 5/28/10 粒子物理宇宙学

1.1o1.1o simulated shear field by Hamana

()

(+)

E

B

EEEE

P FT

0

θθθθ Correlation Function

Power Spectrum

Hoekstraet al (2005)

Song & Knox(2004)德州学院 5/28/10 粒子物理宇宙学

德州学院 5/28/10

• BAO distance errors are smaller than WL ones.• BAO growth constraints are from the nonlinear power spectrum.• WL growth rates are not affected by other cosmological parameters.

粒子物理宇宙学

Zhan et al. (2009)

• Projection of errors of distance eigenmodes onto w0‒wa space.

•5 WL distance eigenmodes account for most of the WL constraints on w0 & wa.

• BAO & WL are highly complementary.

德州学院 5/28/10 粒子物理宇宙学

德州学院 5/28/10

Projected 68% likelihood contours of the parameter describing the effective modification to the lensing potential, and the growth index for weak lensing surveys from a full sky survey with median z = 0.9 and surface densities of sources of 35, 50 and 75 galaxies per arcminute.

01 a

Amendola et al. (2008)

粒子物理宇宙学

a

mm a

a

ad

aag

01exp

GR≈ 0.55= - GR

德州学院 5/28/10 粒子物理宇宙学