Suzanne Staggs Princeton Rencontres de Blois 1 June

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 The Atacama Cosmology Telescope (ACT): Still More Cosmology from the Cosmic Microwave Background

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 ACT • 6 m off-axis Gregorian telescope • Located at 5200 m (0. 5 mm PWV) • 3 arrays of 1024 TES bolometers each • 148 GHz, 218 GHz, 277 GHz • 18 institutions, 4 continents, PI = Lyman Page 42’ 148 GHz: 1. 4’ resolution 30 K-rt(s) f 3 db ~ 84 Hz

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 The CMB Power Spectrum

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 The CMB Power Spectrum Wm h 2 Baryon density: Wbh 2 Dark energy: WL Optical depth: t Matter density: Primordial amplitude at k 0=0. 002 Mpc-1: DR 2 Wmh 2, Wbh 2, WL, t, DR 2 Image courtesy WMAP science team circa 2007

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 The CMB Power Spectrum Wm h 2 Baryon density: Wbh 2 Dark energy: WL Optical depth: t Matter density: Wmh 2, Wbh 2, WL, t, DR 2 ns, running of ns, Neff, Yp, lensing, 8 (SZ), point sources Primordial amplitude at k 0=0. 002 Mpc-1: DR 2 Primordial scalar index: ns Running of ns: dln ns/ dln k # Relativistic species: Neff Primordial He abundance: Yp Gravitational lensing: AL Cluster SZ contributions: 8 Point sources (radio, IR, clustered and Poisson)

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 The Sunyaev Zeldovich (SZ) Effect The CMB scatters off electrons in the hot gas of clusters of galaxies, parameterized by the Compton y: where Te and Ne describe the temperature and number density of the electrons in a cluster.

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 The Sunyaev Zeldovich Effect: Clusters in the CMB Power Spectrum At l = 3000, the power spectrum has multiple contributions: primordial fluctuations, the SZ contribution, and sources (radio and dusty galaxies). • Low mass clusters and other hot gas are not resolved but impact the power spectrum • B 3000 = 7+- 3 K 2, ~ independent of template • Models are required to connect to 8 -- consistent with 8 =0. 75 +-0. 05 • (cf 8 =0. 80 +-0. 04 from WMAP 7+BAO+SN, and 8=0. 77+0. 03 from Xray clusters – Vikhlinin et al 2009)

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 Lensing at 3 in CMB Power Spectrum Lensed Unlensed Parameterize such that AL=1 is predicted lensing; AL=0 is nonlensing. Find: AL = 1. 3+-0. 5 at 68% CL Higher order statistics are better -- but lensing is seen even in the power spectrum!

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 The Damping Tail of the CMB Power Spectrum Primordial scalar index: ns Running of ns: dln ns/ dln k # Relativistic species: Neff Primordial He abundance: Yp ns, running of ns, Neff, Yp Can also help break the degeneracy between ns and r, the ratio of scalar to tensor fluctuations

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 The Damping Tail of the CMB Power Spectrum Running of ns: dln ns/ dln k; # Relativistic species: Neff; Primordial He abundance: Yp

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 Testing Inflation with the Power Spectra Primordial power spectrum P(k) described as power law in the wavevector k. Canonical values shown as crosshairs: ns=1 (flat spectrum), dns/d ln k = 0 ns = 0. 962 +- 0. 013 3 different from 1 (ACT +WMAP) Ratio of tensor to scalar fluctuation amplitudes, r, varies with the inflation energy scale Polarization B-modes will constrain r better soon!

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 Particle Physics in the Power Spectra • The 2. 984 +- 0. 008 neutrino species measured from the width of the Z boson contribute 11% of the energy density at the time of last scattering! • Neff = number of relativistic particle species, • Neff affects when matter density begins to dominate energy budget & suppresses early acoustic oscillations in CMB • Nominally 3 neutrinos -- data consistent. • CMB data alone now bound Neff from above! • Recent measurements: • Neff = 5. 3 +- 1. 3 (ACT +WMAP) • Neff = 3. 85 +-0. 62 (SPT +WMAP – Keisler et al 2011) • Neff= 4. 34+-0. 88 (WMAP + BAO, Komatsu et al 2010) • Neff = 3. 77+0. 67 (WMAP + optical data, Reid et al 2010)

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 Nuclear Physics in the Power Spectra • Yp = fraction of primordial helium • BBN prediction as dotted line • More helium --> smaller electron density --> more Silk damping • No-helium universe ruled out at 6 --> independent confirmation of BBN! Note – more primordial Helium decreases the number of electrons at recombination, increasing the photon diffusion length more damping.

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 Beyond the Power Spectrum The Sunyaev Zeldovich (SZ) Effect: ACT Cluster Yield (to date) Figure courtesy of T. Marriage • 50 clusters (148 GHz only -- southern 2008 data and preliminary SDSS Stripe 82 2009 data) • 37 SZ-discovered (not only ACT) • Median z = 0. 45 • Analysis still underway! Marriage et al 2010 b Optical confirmations of first 23 clusters: Menanteau et al, 2010 (using SOAR and NTT)

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 Beyond the Power Spectrum: ACT SZ Measurement of 1013 -1014 Msun Groups/Clusters SZ effect ~ independent of z. But: cluster cosmology requires the Y-M relation! STACKING to find SZ from groups and clusters associated with luminous red galaxies from SDSS Stripe 82. 1) Y from DTsz (sims) 2) M from: • Weak lensing (Reyes et al 2008) • Halo bias (Seljak et al 2005) • Halo bias (Reid et al 2010) Hand et al, 2011, 1101. 1951 “Both data sets are rich and have multiple components, with possible correlations among them, that we will be sorting out as the data and our understanding improve. ”

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 Beyond the Power Spectrum: First Detection of Gravitational Lensing from the CMB Alone Typical 3’ shift, but convergence spectrum peaks at l = 50: large & small scales coupled (non Gaussian)! Simulated difference between lensed and unlensed CMB in 10 ox 10 o patch Data from ACT 4 pt function Das et al, 2011, 1103. 2124 (accepted for PRL)

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 Extending the Power Spectrum: Dark Energy from the CMB Alone The lensing probes the universe at z~0. 2, breaking the dark energy/matter/curvature degeneracy in the CMB power spectrum alone. Sherwin et al, 2011, 1105. 0419 (accepted for PRL)

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 Under the Power Spectrum: Fitting ACT data for the Primordial P(k) in bins PRIMORDIAL P(k) P(k, z=0) Hlozek et al, 2011, 1105. 4887

Suzanne Staggs (Princeton) Rencontres de Blois, 1 June 2011 The Future for ACT • • • More clusters, cosmology with clusters Improved parameters from improved spectra (more, deeper maps) Cross-correlation of lensing convergence spectrum with LSS tracers – probing the growth rate of structure Polarization capability: ACTPOL (funded) Measuring early dark energy, w, and constraining the sum of the neutrino masses ACTPOL: 4 x More Sensitive than MBAC • • Larger field of view (5 x) More detectors at 150 GHz (feedhorn coupled) Improved noise performance Colder bath temperature M. Niemack et al. 2010 (1006. 5049) Forecast m to 0. 07 e. V (not all systematics modeled yet)

THE END

ACT 2008 data papers & • • Hincks et al 2010 Fowler et al 2010 • • • Swetz et al 2011 Marriage et al 2011 Menanteau et al 2010 723, 1523 ‘Beam Profiles and First SZ Cluster Maps’, Ap. JS 191, 423 ‘A Measurement of the 600< ell <8000 Cosmic Microwave Background Power Spectrum at 148 GHz’, Ap. J 722, 1148 ‘The Receiver and Instrumentation’, 1007. 0290, accepted Ap. J ‘Extragalactic Sources at 148 GHz in the 2008 Survey’, Ap. J 731, 100 ‘Physical Properties and Purity of a Galaxy Cluster Sample Selected via the Sunyaev-Zel'dovich Effect’, Ap. J • Hajian et al 2010 • Das et al 2011 • • Dunkley et al 2011 Sehgal et al 2011 • Hajian et al 2011 ‘A Measurement of the CMB Power Spectrum at 148 and 218 GHz from the 2008 Southern Survey’, Ap. J 729, 62 ‘Cosmological Parameters from the 2008 Power Spectra’, 1009. 0866 ‘Cosmology from Galaxy Clusters Detected via the Sunyaev-Zel'dovich Effect, ’ Ap. J 732, 44. ‘Correlations in the (Sub)millimeter background from • Hand et al 2011 and Das et al 2011 ‘Detection of Sunyaev-Zel'dovich Decrement in Groups Clusters Associated with Luminous Red Galaxies, 1101. 1951 ‘Detection of the Power Spectrum of CMB Lensing, ’ accepted PRL, Sherwin et al 2011 alone ‘Evidence for dark energy from the cosmic microwave background using the Atacama Cosmology. Telescope lensing measurements, ’ • • 1009. 0777 ACTx. BLAST’, 1101. 1517 1103. 2124 ‘Calibration with WMAP Using Cross-Correlations’,