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Observational Cosmology - a laboratory for fundamental physics. MPI-K, Heidelberg 24.11.2011 Marek Kowalski . Outline. Introduction Cosmological probes Cosmological constraints. Our Cosmological Framework derives from…. Observation: The Universe is Expanding

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Observational cosmology a laboratory for fundamental physics

ObservationalCosmology - a laboratoryfor fundamental physics

MPI-K, Heidelberg 24.11.2011

Marek Kowalski


Outline

  • Introduction

  • Cosmologicalprobes

  • Cosmologicalconstraints


Our cosmological framework derives from
Our Cosmological Framework derives from…

Observation: The Universe is Expanding

Principles: Homogeneous, isotropic

Theory: General Relativity

Friedman Equation, which governs expansion


Our cosmological framework derives from1
Our Cosmological Framework derives from…

Observation: The Universe is Expanding

Principles: Homogeneous, isotropic

Theory: General Relativity

Friedman Equation, which governs expansion

Matter Density


Our cosmological framework derives from2
Our Cosmological Framework derives from…

Observation: The Universe is expanding

Principles: Homogeneous, isotropic

Theory: General Relativity

Friedman Equation, which governs expansion

Matter Density

Cosmological Constant/ Dark Energy


Our cosmological framework derives from3
Our Cosmological Framework derives from…

Observation: The Universe is expanding

Principles: Homogeneous, isotropic

Theory: General Relativity

Friedman Equation, which governs expansion

Matter Density

Cosmological Constant/ Dark Energy

Curvature


1998 discovery of dark energy

M

1998: Discovery of Dark Energy


Nobel prizeforphysics2011


Nobel prizeforphysics2011


The standard model of cosmology cdm
Thestandardmodel of cosmology: ΛCDM

Ingredients of ΛCDM:

  • Cosmologicalconstant

  • Cold Dark Matter

  • Baryons

  • 3 light neutrinoflavors

  • Ampl. of primord. fluctuations

  • Index of power spectrum


The standard model of cosmology cdm1
Thestandardmodel of cosmology: ΛCDM

Beyondthestandardmodel:

  • Non-Λdarkenergy

  • Hot dark matter,

    e.g. massive neutrinos

  • Additional relativisticspecies,

    e.gextra neutrinospecies

  • Tensorperturbations

    & runningspectralindex

    ⇒ physics of Inflation


CosmologicalProbes:

Selectednewresults


CosmicMicrowave Background

New groundbaseddata from:

South Pole Telescope (SPT) &

Atacama CosmologyTelescope (ACT)

WMAP

ACT – 6 m telescope

Planck: 2009 - 2011


CosmicMicrowave Background

New groundbaseddata from:

South Pole Telescope (SPT) &

Atacama CosmologyTelescope (ACT)

WMAP

WMAP: 2001 - ?

SPT

CMB fit with

forground;

SPT-afterfilter

w/o forground

4σ detections of CMB weaklensing


Galaxy Clusters

CMB footprint

X-rayfootprint

Picture credit: ESA

First scienceresults of Planck (A&A, 2011)


Sne ia hubble diagram
SNeIa Hubble Diagram

A bit

brighter M

fainterthen

expected

normalization

  •  M

  • 1 0

  • 0.72 0.28

  • 0 1

Supernova Cosmology Project (SCP)Kowalski et al. (2008)

fainter


Sne ia hubble diagram1
SNeIa Hubble Diagram

  •  M

  • 1 0

  • 0.72 0.28

  • 0 1

Supernova Cosmology Project (SCP)Kowalski et al. (2008)

HST

SNLS

Essence

fainter

SDSS

PanStarrs

PTF

SNF

CfA


SNe at large Redshifts (z>1)


HST Survey of Clusters with z ≥ 1

Survey of z>0.9 galaxyclusters

⇒ SNefromcluster & field

⇒ about 2 x moreefficient

⇒ enhencement of earlyhosts

⇒ 20 new HST SNe

⇒ 10 high quality z>1 SNe!

Cycle 14, 219 orbits (PI S. Perlmutter)

24 clusters from RCS, RDCS,IRAC, XMM

Supernova Cosmology Project

Suzuki et al., 2011


Hst survey of clusters with z 1
HST Survey of Clusters with z ≥ 1

Supernova Cosmology Project

Suzuki et al., 2011


Hst survey of clusters with z 11
HST Survey of Clusters with z ≥ 1

Union 2.1 - 580 SNe


BaryonAcousticOscillation

Acoustic „oscillation“ lenghscalefrom CMB visible in thedistribution of galaxies ⇒ Standard ruler of cosmology.

Sloan Digital Sky Survey


BaryonAcousticOscillation

Acoustic „oscillation“ lenghscalefrom CMB visible in thedistribution of galaxies ⇒ Standard ruler of cosmology.

WiggleZsurvey – Blake et al, 2011


BaryonAcousticOscillation

Acoustic „oscillation“ lenghscalefrom CMB visible in thedistribution of galaxies ⇒ Standard ruler of cosmology.

Promisingtechnique & muchactivity: BOSS, HETDEX,...


CosmologicalConstraints:

Selectednewresults


ΛCDM

SNe (Union 2.1, Suzuki et. al, 2011)

BAO (Percival et. al, 2010)

CMB (WMAP-7 year data, 2010)

Supernova Cosmology Project

Suzuki et al., 2011

ΩΛ=0.729 ± 0.014

and allowing for

curvature:

Ωk=0.002 ± 0.005


Fundamental problems of vacuum energy cosmological constant

Whynow?

Matter: r R-3

Vakuum Energy: r = constant

Fundamental Problems of VacuumEnergy/CosmologicalConstant:

  • Why so small?

  • Expectation: rL ~ (Mplanck)4

  • 120 orders of magnitudes larger thentheobservedvalue!

Dark Energy with

equation-of-state:

p=wr

(p = pressure; r = density)

 ρ R -3(1+w)


Dark Energy

Supernova Cosmology Project

Suzuki et al., 2011

Equation of state: p=wρ

Constant w:

w=-0.995±0.078

cosmological

constant


Dark Energy

Supernova Cosmology Project

Suzuki et al., 2011

Equation of state: p=wρ

Constant w:

w=-0.951±0.078

Redshiftdependent w:

w(a)=w0+(1-a)xwa

Wa = 0.14±0.68

Λ

cosmological

constant

No deviationfrom

w=-1 (i.e. Λ)


Redshift dependent eos
Redshiftdependent EOS

A floating non-SNe bin to decouple

low from high-redshift constraints

Assuming step-wise constant w:

~20% improved

constraints


Constraints on Inflation parameters

e.g. Chaotic Inflation (Linde, 1983)

Power spectrum of

curvatureperturbations


Constraints on Inflation parameters

e.g. Chaotic Inflation (Linde, 1983)

Power spectrum of

curvatureperturbations

Tensor-to-scalarratio (r)

Scalarspectralindex

ns =0.966±0.011

Tensor-to-scalarratio

r<0.21

scalarspectralindex (ns)

SPT+ WMAP7 (Keisler et al. 2011)


Number of relativisticspecies (neutrinos!)

CMB (& BaryonNucleosynthesis) sensitive to number of neutrinospeciesNeff

SPT+WMAP7: Neff= 3.85±0.62 (68% CL)


Neutrino massfrom CMB & large scalestructure

Damping of correlation power due to freestreaming at epoch of radiation-matterequality:

Tegmark et al. 2004

Combination of

CMB+BAO+H0:

e.g. Komatsu et al (2010)

Similarmassbounds also for

LSND-like sterile neutrinos

Hamann et al (2010)


Summary

  • Cosmology today is about precision

  • Multiple probes for highest sensitivity

  • ΛCDM looks strong so far – despite interpretational problems with dark energy

  • Many new surveys committed, hence significant progress expected!


Counting galaxy clusters
CountingGalaxy Clusters

Vikhlini et al. ApJ, 2009

Upcomingsurveys: eROSITA, DES, ...


Redshift dependent eos1
Redshiftdependent EOS

A floating non-SNe bin to decouple

low from high-redshift constraints

Assuming step-wise constant w:


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