Testing the concordance cosmology with weak gravitational lensing

Transcription

1 Testing the concordance cosmology with weak gravitational lensing Ali Vanderveld (University of Chicago) with Tim Eifler, Wayne Hu, Michael Mortonson, and Jason Rhodes Case Western Reserve University, March 20th, 2012

2 The concordance model Collisionless dark matter DE DM + + Atoms Smooth dark energy (Λ?) Allen et al Gaussian initial fluctuations General relativity

3 Testing the status quo Expansion history observables: Local H0 Baryon acoustic oscillations Type Ia supernova D(z) Predictions for future structure-growth observables Flat ΛCDM + Initial fluctuation spectrum from the CMB CosmoMC + Cosmological paradigm: Flat ΛCDM Curved quintessence Early dark energy, etc... Future structure observations could potentially falsify these paradigms Mortonson, Hu, and Huterer 2008, 2009, 2010 AV, Mortonson, Hu, and Eifler 2012

4 Pink elephants Predicted mean full-sky abundance of clusters with M > h -1 M z >1.48 Observation of a single massive high-redshift cluster could falsify the concordance model, or even possibly the entire smooth dark energy paradigm Mortonson, Hu, and Huterer 2010

5 Weak lensing Ψ = projected gravitational potential A ij = " ij + # 2 $ #% i #% j * & 1+ ' + ( ( - 1 2, / + ( 1+ ' ) ( 2 1. Galaxy ellipticity is an estimator of the shear: Cosmic shear a direct tracer of mass e i " 2# i (in the concordance model) e.g. Massey et al. 2007

6 The pipeline Data sets: SNe from Kessler et al WMAP7 temperature and polarization BAO from Percival et al Local Hubble constant from SHOES Parameter set + θ 0 = {Ω b h 2, Ω c h 2, τ, θ A,n s, ln A s } N max w(z)+1= α i e i (z) Joint posterior distribution for our parameter set i=1 Posterior probabilities for derived statistics Distance-redshift relation Growth function z=0 linear matter power spectrum + Halofit Nonlinear matter power spectrum l 2 P κ 2π = 9π 4c 4 l Ω2 mh dz D3 H g 2 (z) a 2 2 NL Source redshift distribution + n(z) l D(χ),z ( z z 0 α z exp z 0 Cosmic shear predictions β

7 Flat ΛCDM predictions 2-point correlation function DES power spectra Schrabback et al Benjamin et al AV, Mortonson, Hu, and Eifler 2012

8 Generalizing the model Curvature well constrained by WMAP7 Bias towards lower power for general w(z) A shear excess could falsify the entire smooth dark energy paradigm

9 Systematic uncertainties Matter power spectrum Distance scale WDM baryons

10 Future lensing surveys Dark Energy Survey The High Altitude Lensing Observatory Euclid (Europe) WFIRST (US)

11 The High Altitude Lensing Observatory PI: Jason Rhodes (JPL) Project manager: Jeff Booth (JPL) JPL: Paul Brugarolas, Ben Dobke, Eric Jullo, Kurt Liewer, Chris Paine, Michael Seiffert, James Wu Caltech: Richard Ellis, Sergio Pellegrino, Roger Smith, Harry Teplitz Chicago: Ali Vanderveld Wallops Flight Facility: Raymond Lanzi, David Stuchlick NOAJ (Japan): Satoshi Miyazaki ETH Zurich: Adam Amara, Simon Lilly, Udo Wehmeier Edinburgh (UK): Tom Kitching, Richard Massey, John Peacock Durham (UK): Ray Sharples, Paul Clark, Richard Meyers UKATC: David Lunney, David Henry, Naidu Bezawada e2v: Roger Pittock

12 Amara and Réfrégier 2007 Optimal surveys

13 Ballooning NASA s Ultra Long Duration Balloon program 54 day Antarctic flight in 2009, 100 day flights on the drawing board km altitude 7 million cubic foot (MCF) balloon flown, 14 and 22 MCF planned ~1% the cost of a space mission Columbia Scientific Balloon Facility

14 Achieving space quality Coarse pointing Fig. 4. Sample station-keeping data from a WASP hang test. T target error nulling (0.22!! RMS) with the mechanical configuratio Fine pointing Fig. 1. A general multi-stage pointing control architecture for sub-arcsecond pointing stability. The top block refers to the gondola control and the interface to the lower block, which is the instrument-level fine guidance system. The fine guidance system combines sensor information from guide CCDs and the angular rate sensors (ARSs) in order to drive a Fine Steering Mirror (FSM) control loop to correct for jitter. This generates a fine guidance signal to the Wallops Arcsecond Pointing (WASP) system for improved telescope body pointing. * Also thermal control angle between a fixed direction on the telescope and the direction to the north celestial pole) will be able to track the same guide stars throughout the night. This guarantees high-performance centroiding and attitude control using standard control algorithms. The default HALO design uses the WASP system plus an extra WASP bearing/motor placed at the rear of the telescope to directly rotate the telescope about the line of sight (see the right hand side of Figures 2 and 3). However, as described in Section 3.2, we are considering other options for the rotational correction that do not include a motor at the rear of the telescope. The assessment of the field rotation matrices and dynamics along with a comparison of 3- and 4-frame gondola p ti fo w n T p F fo w ta F ci o

15 Science reach Seeing-limited observations: Weak and strong lensing Exoplanets Galaxy surveys Stars within our galaxy

16 Conclusions We can use current expansion history data to robustly predict future structure growth data With these predictions in hand, future weak lensing observations could potentially falsify the concordance model (see arxiv: ) The High Altitude Lensing Observatory could gather this data in the near term (see white paper on the arxiv in the coming months)