The Dark Universe 1.The Universe Observed 2.Early Universe Basics 3.Inflationary Cosmology 4.The Big Questions Michael S. Turner Kavli Institute for Cosmological Physics The University of Chicago

Today’s “Consensus Cosmology” Today’s “Consensus Cosmology” based upon precision measurements From quark soup to nuclei and atoms to galaxies and large-scale structure Flat, accelerating Universe Atoms, exotic dark matter & dark energy Consistent with inflation Precision cosmo parameters –Ω 0 = ± (uncurved) –Ω M = ± –Ω B = ± –Ω DE = 0.73 ± –H 0 = 70.4 ± 1.3 km/s/Mpc –t 0 = ± 0.11 Gyr –N ν = 4.34 ± 0.9 Consistent with all data, laboratory and cosmological!

Michael S Turner Cosmology is a young science its story only begins 90 years ago (Hubble, Einstein)

Michael S Turner : General Relativity & Λ

Michael S Turner 1929: Just One Number K 1929: Just One Number K (error bars not needed, velocity in km) Hubble & Humanson: few 100 galaxies, z < 0.1 K (H 0 ) = 550 km/s/Mpc

Gamow’s Hot Big Bang “alpher, bethe, gamow,” 1948

1948: Steady State Theory

Michael S Turner Cosmology: The Search for Two Numbers Cosmology: The Search for Two Numbers … Sandage 1970

Michael S Turner Landau on Cosmologists Often in Error, Never in Doubt!

Michael S Turner Discovery of Cosmic Microwave Background, 1964

< sec Do Not Enter! From the Big Bang to Us

Michael S Turner “The Standard Model” Hot Big Bang (circa 1972) “Reality (physics) Based” BBN (nuclear physics) CMB (atomic physics) Structure Formation (grav. physics) Begins at 0.01 sec Ω 0 ~ 0.1 (baryons) Big Questions “The naughts”: H 0, t 0, Ω 0 Large entropy per baryon Hadron Wall Origin of density perturbations

The Hadron Wall S. Weinberg in Gravitation & Cosmology

1980: Fall of “The Hadron Wall”

New ideas from particle physics

Michael S Turner 1980s: The Go Go Junk Bond Days of Early Universe Cosmology “Creativity Based” InflationInflation Cosmic StringsCosmic Strings BaryogenesisBaryogenesis Magnetic MonopolesMagnetic Monopoles Phase TransitionsPhase Transitions Hot and Cold Dark MatterHot and Cold Dark Matter Decaying ParticlesDecaying Particles Kaluza-KleinKaluza-Klein

Michael S Turner 1990s: Beginning of Data-driven Cosmology COBE! and CMB experiments Redshift surveys (CfA, IRAS, 2dF, SDSS) Large-scale velocity field measurements Gravitational lensing Big telescopes (Keck, …) with big CCD cameras HST, X-ray, gamma-ray, IR, …

Michael S Turner 1992: COBE Maps & Blackbody Spectrum

Big Glass on the Ground: 4 VLT, 2 Kecks, 2 Geminis and 2 Magellans

Great Observatories in Space: Hubble, Spitzer, Chandra, and Fermi

Giant CCD Cameras 100 Megapixel Gigapixel

How far can you see on a clear day? Back to the birth of galaxies

Star formation peaked 13 billion years ago, almost done

Michael S Turner 2000s: Era of Precision Cosmology “Fisher Based” Cosmological parameters Tests of inflation, CDM Correlating large, complex data sets Cosmological Consistency Physical parameters (e.g., neutrino mass)

Michael S Turner In the midst of a revolutionary period of discovery -- powerful ideas and instruments

Michael S Turner Two Really Important Ideas That Changed Cosmology Two Really Important Ideas That Changed Cosmology with deep connections between quarks and the cosmos Inflation: Inflation: brief period of rapid (accelerated) expansion accounts for smoothness, flatness; heat of the big bang; and seed inhomogeneities Particle dark matter: Particle dark matter: bulk of the dark matter that holds the Universe together resides in a sea of elementary particles left over from the big bang

Michael S Turner The Consensus Cosmology The Consensus Cosmology supported by large body of observations

QUAD BOOMERanG DASI CMB Experiments Maxima CBI VSA ACBAR CBI

Michael S Turner The Universe circa 380,000 yrs The Universe circa 380,000 yrs WMAP ±0.001% Fluctuations

Michael S Turner Curve = concordance cosmology

Michael S Turner

CMB anisotropy is a non-trivial map of density inhomogeneity to temperature fluctuations: Mapping depends upon cosmological parameters (good news!) ΩMh2ΩMh2

H 0 = 72 ± 1 ± 4 km/s/Mpc

… and Dr. Sandage, H 0 is now measured and q 0 is negative!

Two Technological Enablers: 1.Large (100 Mpixel) CCD Cameras 2.SNe Ia: Bright, 2.SNe Ia: Bright, Standardizable Candles (1.4 solar mass bomb)

The Discovery Data Perlmutter et al, 1999 Riess et al, 1998

Carl Sagan: Extraordinary Claims Require Extraordinary Evidence

Michael S Turner Curve = concordance cosmology Ω 0 = ± Ω M = 0.28 ± only consistent if Ω Λ-like = 0.72 ± 0.015

1000 SNe from: the original teams + SNLS, ESSENCE, SDSS, CfA, CSP, … More data stronger signal

SDSS-II Supernova Survey ~500 Well studied SNe Ia, suitable for framing

Evidence for past acceleration: Important reality check HST ACS Sample of high-z SNe: A. Riess et al, Ap.J 607, 665 (2004)

Baryon Acoustic Oscillations (BAO): Zel’dovich’s Standard Ruler

Clusters as Standard Rulers Use constancy of the baryon-to-total mass ratio as a standard ruler S. Allen et al, MNRAS 353, 457 (2004); 383, 879 (2007)

Michael S Turner Stand alone evidence for cosmic acceleration from clusters observed by Chandra A.Vikhlinin et al, ApJ 692, 1060 (2009) [arXiv: ] 36 Clusters w/ ~0.55 and 49 w/ ~0.05

Michael S Turner

Consistent with all observations: Ω Λ = 0.71 ± 0.02

… in any case, the extraordinary evidence is now in place

Dark Energy Defining features: Large negative pressure, p ~ -ρ, so that (ρ + 3 p) < 0 w = p/ρ (equation-of-state parameter) ~ -1 Smoothly distributed Not particulate (dark matter has p ~ 0) Simplest example: Energy of the quantum vacuum: w = -1

Dark Energy: Ω DE = 0.76 ± 0.02 w = ± 0.1 (± 0.1 sys) Where We Are Today

Allow w to vary: w = w 0 + w a (1-a) a = scale factor Ω DE = 0.76 ± 0.02 w 0 = -1 ± 0.2 w a ~ 0 ± 1 Possible variation is not well constrained No Reason to Believe w is Constant

Cannot Understand Our Cosmic Destiny Until We Understand What Dark Energy Is! In the Presence of Dark Energy, a Flat Universe Can Expand Forever, Re-collapse, or Even Experience a Big Rip!

BAO: SDSS/2dF, WiggleZ, FMOS, BOSS HETDEX, WFMOS, PAU  EUCLID & JDEM CL: SZA, SPT, DES, ACT, Chandra  eROSITA SNe: DES, PanSTARRS  LSST, EUCLID & JDEM WL: DES, PanSTARRS  LSST, EUCLID & JDEM CMB et al: WMAP/ACT/SPT/Planck – cosmological degeneracies make many other observations valuable On the way to few % in w 0, 10% in w a, significant tests of underlying gravity theory … and deeper understanding of dark energy Impressive Array of Dark Energy Projects on the Horizon

Probing Cosmic Acceleration and Dark Energy Primary effect is on the expansion rate Expansion rate controls distances, structure growth Two Qualitatively Different Probes –Geometric: distances –Dynamic: growth of structure –NB: if not GR, changes in growth, lensing

Michael S Turner Interlocking Web of Measurements Age: CMB, expansion, age of oldest globular clusters, WD cooling, radioactive element Hubble constant: SNe, CMB, Lensing, SZ, 1,000,000+ redshifts (out to z = 8) CMB anisotropy + polarization: multiple experiments Matter, baryon densities: CMB, BBN, lensing, …

Consistent Age for Universe

Michael S Turner CMB (first to second peak) Ω b h 2 = ± vs. BBN (Deuterium) Ω b h 2 = ± ~5% agreement Ω b = ± Precision Cosmology Indeed! h = H 0 /100 km/s/Mpc ~ 0.7

Michael S Turner Sloan Digital Sky Survey sdss.org Large-scale structure: Distribution of 10 6 galaxies in the Universe today

Michael S Turner Tracing the history from a slightly lumpy Universe to galaxies ablaze

Successes of Consensus Cosmology Consistent with a large body of high quality lab and cosmological data Detailed history from quarks to us Handful of input data (parameters – similar to standard model of particle physics)

Mysteries of Consensus Cosmology Dark Matter Dark Energy Inflation Baryogenesis Before the Big Bang

Michael S Turner

The Universe

Michael S Turner A Universe Full of Galaxies and Clusters of Galaxies galaxies! Density of galaxies: ~0.001/Mpc 3 Typical mass solar mass (2 x g) Range: 10 6 to solar masses

Michael S Turner

Some Galaxy Numbers Galaxy masses: 10 6 to M O dN = φ * [L/L * ] α exp[-L/L * ] dL/L * –φ * = ± (h -1 Mpc) -3 = (5.8 Mpc) -3 –α = ± 0.05 –L * = 1.4 x L O (Milky Way, Andromeda) Cluster masses: to M O NB: Mpc = 3.26 Mlyr = 3.09 x cm = 1.56 x GeV -1

Michael S Turner

Coma Cluster of Galaxies Masses from to solar masses, dN/dM α M -2.5, and ~ 10 6 total, 5% of galaxies are found in rich clusters X-ray bright (hot gas)

Some Cluster Numbers Galaxy cluster masses: to M O (small groups to “rich clusters” of 1000’s of galaxies) Million galaxy clusters in the observable universe dN/dM α M -2.5 Clusters cluster! Superclusters (largest almost bound objects)

Michael S Turner Isotropy (same in all directions): Galaxy Distribution on Sky

Michael S Turner Isotropy & Homogeneity: at 400,000 yrs CMB Intensity Scale: ±0.01%

Michael S Turner Sloan Digital Sky Survey sdss.org

Michael S Turner Zwicky and cluster dark matter

Michael S Turner 1970s: Vera Rubin and Flat Rotation Curves Dark Matter Close to Home

Michael S Turner Flat rotation curves of galaxies (galaxies have large, dark halos) Clusters are held together by dark matter (galaxy motions, lensing maps, x-ray gas) CMB/BBN census of stuff in the Universe Without gravity of dark matter cannot make observed structure CDM has most of the truth Flat rotation curves of galaxies (galaxies have large, dark halos) Clusters are held together by dark matter (galaxy motions, lensing maps, x-ray gas) CMB/BBN census of stuff in the Universe Without gravity of dark matter cannot make observed structure CDM has most of the truth Overwhelming Evidence for Dark Matter

Michael S Turner Airtight Evidence for Nonbaryonic Dark Matter CMB & BBN Ω b h 2 = ± vs. CMB/SDSS Ω M h 2 = 0.13 ± σ discrepancy

Michael S Turner Need for DM comes at different length scales (constant a = v 2 /r ~ H 0 – Milgrom Miracle) Less concentrated  weakly interacting (uncharged) Cold (small velocity dispersion) – structure formation Non baryonic (accounting + don’t see it) Need for DM comes at different length scales (constant a = v 2 /r ~ H 0 – Milgrom Miracle) Less concentrated  weakly interacting (uncharged) Cold (small velocity dispersion) – structure formation Non baryonic (accounting + don’t see it) What Astrophysics Tells Us About Dark Matter

Michael S Turner Stars: ~0.5% Atoms: 4.5 ± 0.2% Dark Atoms: ~4% (90% of atoms) Exotic Dark Matter: 23 ± 1.5% Neutrinos: 0.1% to 2% …. the rest is dark energy Stars: ~0.5% Atoms: 4.5 ± 0.2% Dark Atoms: ~4% (90% of atoms) Exotic Dark Matter: 23 ± 1.5% Neutrinos: 0.1% to 2% …. the rest is dark energy Dark Numbers

Michael S Turner Stars: ~2% Hot gas ~14% Exotic Dark Matter ~84% Consistent with universal mass ratios: 0.5::4.0::23 Stars: ~2% Hot gas ~14% Exotic Dark Matter ~84% Consistent with universal mass ratios: 0.5::4.0::23 Clusters: Nature’s Fair Sample

Michael S Turner Dark Matter Candidates

Michael S Turner Cosmological Redshift All physical distances get stretched with cosmic scale factor, R today = 1.0 Wavelength of a photon (redshift z) Momenta of particles too: p ~ 1/R Distance between galaxies NB: but not the size of self-bound objects (from atoms to stars to galaxies & clusters)

Redshifted Spectra Ca H, K lines (~3950 Å in Lab) BLUE RED 3950 Å

Michael S Turner UV light (1216 Å) from the early Universe redshifted to near IR. The Universe was ~7 times smaller!

z = 6.43 Quasar: When the light was emitted, Universe was 7.43 x smaller! 1216 Å

Record holder: z = 8.6!

Michael S Turner Expansion = Scaling up Single “Cosmic Scale Factor” R(t) Summarizes Expansion

Michael S Turner Friedmann Equations Friedmann Equations Matter tells space how to bend (“flat”, Euclidean Universe) H = expansion rate (“Hubble constant”) Total energy density ρ and total pressure p Solutions:

Michael S Turner Our Universe

Michael S Turner Cosmological Parameters

Michael S Turner Evolution of Matter/Energy Evolution of Matter/Energy space tells matter how to move

Michael S Turner Three Epochs Dominated by Different Forms of Energy 1. Rad dominated R ~ t 1/2 thermal bath R < 10 -4, t < 10 4 yrs 2. Matter dominated R ~ t 2/3 struc. forms t ~ 10 4 yrs – yrs 3. Dark Energy R ~ e Ht accelerated expansion t > yrs

Michael S Turner Expand density field in comoving fourier components (which contain fixed amount of matter) but whose physical wavelength grows with time

Michael S Turner During matter- dominated era, wave amplitudes grow with time (as the scale factor), reach unity and bound structures form and cease expanding

Michael S Turner The Physics of Structure Formation (simplified) 1. Creation of Density Inhomogeneities 2. Outside Horizon λ > H -1 Kinematic Evolution 3. Inside Horizon λ > H -1 Dynamic Evolution Inflation

Michael S Turner “Jeans’ Equation” Solutions 1. H = 0: δ k α exp[(4πGρ M ) 1/2 t] Classic Jeans’ Instability 2. H = 2/3t (MD): δ k α t 2/3 α R(t) 3. H = 1/2t (RD): δ k α ln(R) 4. H = const: δ k α const (no growth)

Michael S Turner : Inflation - Flat Universe and origin of density perturbations

Michael S Turner Almost Scale-invariant Perturbations: Hot and Cold Dark Matter Theories

Michael S Turner Inflationary Spectra GalaxyClusterSupercluster Entered horizon RD: const x ln R Entered horizon MD & begin growing

Michael S Turner Structure Forms From the Bottom Up: First Stars (z ~ ) Galaxies (z ~ 2 – 5), Clusters (z ~ 0 - 2), and Superclusters (z ~ 0)

Michael S Turner Cosmic Web of Dark Matter

Michael S Turner Structure Formation Gravitational amplification of small (few parts in 10 5 ) density inhomogeneities to the structure seen today during matter dominated epoch, δρ/ρ α R(t)

Michael S Turner Thermal Bath For most of its early history: thermal equilibrium (departures are very important – not all Fe today!) For kT > mc 2 particle/antiparticle pairs as abundant as photons Energy density: ρ = g * π 2 T 4 /30 g * counts dof

Michael S Turner

Relativistic Degrees of Freedom Quark/HadronAll SM Particles γ/neutrinos e ± pairs

Michael S Turner Radiation-dominated Universe

Big Bang Nucleosynthesis: Theory vs. Observation Michael S Turner

Thermal Equilibrium NSE, n/p~1/6 D leads BBN 1 MeV 0.2 MeV 0.07 MeV 0.01 MeV 10 MeV

Michael S Turner BBN Reaction Network: the big 12

Michael S Turner Reaction Cross Sections are measured where they are needed – no need to extrapolate. Sharp contrast to stellar models

Michael S Turner BBN Predictions (95% cl) Deuterium: baryometer! He-4: go/no-go test of big bang Li-7: consistency test; stellar probe? He-3: probe of chemical evolution

Michael S Turner Light Element Abundances D, He-4 and Li-7 Deuterium: stars only destroy D – need pristine samples of the Universe He-4: MS stars make He-4 – need old, metal poor stars Li-7: also made by cosmic rays, destroyed by stars, He-3: made and destroyed by stars, learn more about chemical evolution!

Michael S Turner

Detecting Deuterium Burles/Tytler, ApJ 499, 699 (1998)

Michael S Turner O’Meara et al: 6 Deuterium Systems D/H = 2.8 ± 0.3 x BBN (Deuterium) Ω b h 2 = ± (D) ± (th)  Y P = ± (D) ± (th) ± (τ n )  Li-7/H = 4.3 ± 0.5 x ?

Michael S Turner CMB (first to second peak) Ω b h 2 = ± vs. BBN (Deuterium) Ω b h 2 = ± ~5% agreement Ω b = ± Precision Cosmology Indeed! h = H 0 /100 km/s/Mpc ~ 0.7

Michael S Turner He-4: 0.24x, Struggling for the 3 rd Sig Fig Y P = ± (D) ± (th) ± (τ n ) ? Biggest issue: control of systematic error (see Peimbert, arXiv: ) State of the art, based upon extragalactic HII regions, Peimbert et al, ApJ 666, 636 (2007): Y P = ± Concordance with D/BBN prediction

Michael S Turner New: Izotov/Thuan (arXiv: ) Y P = ± 0.001

Michael S Turner Neutrino Counting BBN (pre-LEP): N ν < 4 Lab (LEP): N ν = ± BBN (98): N ν < 3.2 (95%) CMB: N ν = 4.34 ± 0.9 BBN (I/T): 3.7± 0.4

Michael S Turner Relativistic Degrees of Freedom Quark/HadronAll SM Particles γ/neutrinos e ± pairs

Michael S Turner Li-7: Not as simple as once thought Li-7/H (D/H) = 4.3 ± 0.5 x Spite plateau: Li-7/H = 1.3 ± 0.3 x Factor of 3 discrepancy (for ~10 years)! Possible explanation: Korn et al, Nature 442, 657 (2006): astration by gravitational settling Inferred value by Korn et al : (3.5 ± 0.8) x

Michael S Turner BBN: GR Independent Quenched Reactor BBN: GR Independent Quenched Reactor Carroll/Kaplinghat, PRD 65, (2002)

Michael S Turner Selected BBN References Recent reviews 1. Schramm/Turner, RMP 70, 303 (1998) 2. Steigman, ARNPS 57, 463 (2007) Predicted abundances and uncertainties 1. Nollett/Burles, PRD 61, (2000) 2.Burles/Nollett/Turner, ApJ 552, L1 (2001) 3. Lopez/Turner, PRD 59, (1999) 4. Cyburt, PRD 70, (2004) 5. Serpico, JCAP 0412 (2004) Serebrov et al, PLB 605, 72 (2005) Deuterium 1. O’Meara et al, ApJ 649, L61 (2006)