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Progress on Cosmology Sarah Bridle University College London.

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Presentation on theme: "Progress on Cosmology Sarah Bridle University College London."— Presentation transcript:

1 Progress on Cosmology Sarah Bridle University College London

2 Progress on Cosmology 1.Definition of “Cosmology” for this talk 2.The latest observations 2.1 Type Ia supernovae 2.2 Galaxy clustering 2.3 Cosmic shear 3.The future

3 Progress on Cosmology 1.Definition of “Cosmology” for this talk 2.The latest observations 2.1Type Ia supernovae 2.2 Galaxy clustering 2.3 Cosmic shear 3.The future

4 My Definition of Observational Cosmology Telescope observations of the Universe aimed at measuring global parameters Cosmic Microwave Background (CMB) – See talk by Francois Bouchet next Large-scale structure of the Universe, especially – Galaxy clustering – Clusters of galaxies – Gravitational lensing Standard candles e.g. Type Ia supernovae

5 Concordance Model 74% Dark Energy 22% Cold Dark Matter 4% Baryonic Matter

6 What Observational Cosmology Measures Post-inflation conditions – Scalar, tensor (+other?) perturbation power spectra The expansion rate (Hubble constant) Baryonic matter density Dark matter – density, distribution – as f(time) Dark energy – density, distribution – as f(time) – Or modifications to GR (see de Rham talk on Friday)

7 Big Bang5 billion years agoToday Credit: Richard Massey, NASA

8 Why is the Universe Accelerating? Einstein’s cosmological constant A new fluid called Dark Energy – Equation of state w=p/  General Relativity is wrong

9 Progress on Cosmology 1.Definition of “Cosmology” for this talk 2.The latest observations 2.1 Type Ia supernovae 2.2 Galaxy clustering 2.3 Cosmic shear 3.The future

10

11 Latest Supernova Compilation Hicken et al 2009 Matter Density Dark Energy Equation of State w Redshift Distance Distance – distance if no DE

12 Progress on Cosmology 1.Definition of “Cosmology” for this talk 2.The latest observations 2.1 Type Ia supernovae 2.2 Galaxy clustering 2.3 Cosmic shear 3.The future

13 Galaxy Clustering Constraints on Dark Energy Hicken et al 2009, showing results using Eisenstein et al 2005 Dark Energy Equation of State w 1-Matter Density

14 Neutrino Mass Constraints from Galaxy Clustering Thomas, Abdalla & Lahav 2010 Matter Density  m

15 Thomas, Abdalla & Lahav 2010 Neutrino mass constraints from galaxy clustering

16 Neutrino mass from galaxy clustering: Sensitivity to assumptions Swanson, Percival, Lahav 2010

17 Progress on Cosmology 1.Definition of “Cosmology” for this talk 2.The latest observations 2.1 Type Ia supernovae 2.2 Galaxy clustering 2.3 Cosmic lensing 3.The future

18 Gravitational Lensing

19

20 Tyson et al 2000 Cosmic Lensing

21 Universe was 0.2 Gyr old Credit: Springel et al. (2005)

22 Universe was 1 Gyr old Credit: Springel et al. (2005)

23 Universe was 4.7 Gyrs old Credit: Springel et al. (2005)

24 Today (13.6 Gyr) Credit: Springel et al. (2005)

25 Results from the HST COSMOS Survey

26

27 In 3 Dimensions

28 Cosmic Shear Parameter Constraints Schrabback et al 2010

29 Progress on Cosmology 1.Definition of “Cosmology” for this talk 2.The latest observations 2.1 Type Ia supernovae 2.2 Galaxy clustering 2.3 Cosmic shear 3.The future

30 The Future JDEM See Moniez talk on Friday

31 Gravitational shear has the greatest potential Big uncertainty largely due to shear measurement techniques Maybe dark energy is the wrong model... Galaxy clustering SupernovaeGravitational shear Comparison of different methods

32 Future prospects Cosmic microwave background radiation – Distribution of dark matter at early times Distribution of galaxies – Some clues to distribution of matter Galaxy velocities – Galaxies fall towards dark matter clumps Gravitational lensing The Dark Energy Survey

33 C3 C1

34 20 000 sq deg RIZ AB ≤ 24.5 at 0.16” FWHM, yielding 30-40 resolved galaxies/amin 2, z~ 0.9 NIR photometry: Y, J, H ≤ 24 (AB, 5σ PS). Spectroscopy. Refregier et al Science Book arxiv:1001.0061 Galactic Plane Deep ~40 deg 2 Wide Extragalactic 20,000 deg 2

35 HST COSMOS

36 End

37 Map in 3d

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39 Hexapod Corrector Lenses CCD Readout Filters Shutter Mechanical Interface of DECam Project to the Blanco Focal plane (detector)

40 Kowalski et al 2008

41 Ground vs Space weak lensing shear space ground

42 Larson et al 2010, WMAP7


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