Photometric redshifts for deep large surveys

1. Photometricredshiftsfordeeplargesurveys PAU- A new point of view Pol Martí Sanahuja IFAE Thursday Meeting April, 23th of 2009

2. New cosmology, new observables • The shape of the universe: • Space-time metric: Space-time Metric Space-time line element Distance between two separated points Space-time metric depends on: - Coordinate system Minkowski metric - Space-time curvature

3. New cosmology, new observables • The shape of the universe: • Cosmological principle: We does not occupy a privileged location in the universe. Universe has the same appearance independently of where you are looking from. Homogeneity and Isotropy of the universe

4. New cosmology, new observables • The shape of the universe: • Friedman-Robertson-Walker (FRW) metric: Cosmological principle +

5. New cosmology, new observables • The shape of the universe: • Friedman-Robertson-Walker (FRW) metric: FRW Minkowski Diferences Scale factor Curvature factor k = 1 -1 0

6. New cosmology, new observables • Cosmological redshift: • Photon’s trip across the FRW metric: Eq. of motion: Geodesic equation Christoffel symbols Geodesic equation + FRW metric + De Broglie hypothesis

7. New cosmology, new observables • Cosmological redshift: • Definition: +

8. New cosmology, new observables • Cosmological redshift: • Consequences on the spectra:

9. New cosmology, new observables • The evolution of the universe: • Einstein equations: Energy-moment. tensor Einstein tensor Ricci Tensor Ricci Scalar Riemann Tensor Christoffel symbols

10. New cosmology, new observables • The evolution of the universe: • Perfect fluid: Energy density Caracterized by its rest frame Pressure • Properties: • No shear stresses • No viscosity • No heat conduction Energy-momentum tensor: Dust State equation: Radiation Curvature

11. New cosmology, new observables • The evolution of the universe: • Friedman-Lematier equation: Einstein equations (with perfect fluid) + FRW Metric Solution: Hubble parameter Density parameter Critical density

12. New cosmology, new observables • Observables: • Angular distance: Standard Ruler + with + FRW metric & evolution

13. New cosmology, new observables • Observables: • Hubble diagram: _________ ______________________________ High-z terms (deep terms) Hubble law High-z terms only depend on the universe multicomponent content

14. New cosmology, new observables • Observables: • Hubble diagram: • 1998: Perlmutter et al. said “Universe expansion is accelerating ” Dark Energy Negative Pressure!

15. New cosmology, new observables What Dark Energy is made of ? More precise measures are required to determine ω accurately and answer this question Deep surveys

16. Measures • BAO scale as standard ruler: • When t < trec= 240.000 yr : Neutrinos Universe components were… Photons Nucleons & electrons Relativistic Highly coupled gas + Cold Dark Matter Initial over-density of components Sound wave Overpressure in highly coupled gas

17. Measures • BAO scale as standard ruler: D. Eisenstein, http://cmb.as.arizona.edu/~eisenste/acousticpeak/

18. Measures • BAO scale as standard ruler: • When t = trec= 240.000 yr : Hydrogen atoms are formed Strong interaction in the gas disappears Overpressure vanishes Wave stalls at a radius of 150Mpc

19. Measures • BAO scale as standard ruler: D. Eisenstein, http://cmb.as.arizona.edu/~eisenste/acousticpeak/

20. Measures • BAO scale as standard ruler: • When t > trec= 240.000 yr : 150Mpc away over-density in gas attracts Dark Matter Galaxies are preferably separated 150Mpc + Dark Matter halos seeds the formation of galaxies Standard Ruler

21. Measures • BAO scale as standard ruler: Standard Ruler D. Eisenstein, http://cmb.as.arizona.edu/~eisenste/acousticpeak/

22. Measures • BAO scale as standard ruler:

23. Measures • BAO scale as standard ruler:

24. Measures • BAO scale as standard ruler: D. Eisenstein, http://cmb.as.arizona.edu/~eisenste/acousticpeak/

25. Measures • BAO scale as standard ruler: • Galaxy-Galaxy correlation function: D. Eisenstein, http://cmb.as.arizona.edu/~eisenste/acousticpeak/ BAO shape D. Eisenstein, http://cmb.as.arizona.edu/~eisenste/acousticpeak/

26. Measures • BAO scale as standard ruler: • Galaxy-Galaxy correlation function: We need enough amount of galaxies to determine accurately galaxy-galaxy correlation function Large surveys

27. Measures • LRG as a mass tracer: LuminousRed Galaxies Most-luminous galaxies in Universe Old stellar systems Universe is full of them Uniform caracterized spectrum Accurated photometric redshift measures! Prove deep cosmological distances! Prove large cosmological volumes!

28. Measures • Photometric redshift: • What do we need? • What do we obtain?

29. Measures • Photometric redshift: • How do we measure it?

30. Measures • Photometric redshift: • How do we measure it?

31. Measures • Photometric redshift: • How do we measure it?

32. Measures • Photometric redshift: • How do we measure it?

33. Measures • Comparison between Photo. and Spectr. redshift: • Uncertains: • Exposure times: σPhoto >> σSpectro tSpectro >> tPhoto Big amount of exposures Photometric redshift are more optimum for large surveys! Large surveys Big statistics

34. Deep and Large Survey • PAU (Physics of the Accelerating Universe): • Features: 14·106 LRGs 8000 deg2 0.1<z<0.9 9 h-3 Gpc3 42 filters σz<0.003(1+z) Benitez et al. 2009 High redshift precision • (σz<0.03(1+z) SDSS filters)

35. Deep and Large Survey • PAU (Physics of the Accelerating Universe): • How do we get this high precision?

36. Deep and Large Survey • PAU (Physics of the Accelerating Universe): • How do we get this high precision?

37. Deep and Large Survey • PAU (Physics of the Accelerating Universe): • How do we get this high precision? Low resolution spectrum

38. Deep and Large Survey • PAU (Physics of the Accelerating Universe): • Why do we need this high precision? PAU survey will detect BAO using • Angular power spectrum Cl A new point of view! + • Radial power spectrum PK

39. Deep and Large Survey • PAU (Physics of the Accelerating Universe): • Why do we need this high precision? σZ<0.003(1+z) is required to measure BAO scale in the line-of-sigth Benitez et al. 2009

40. Deep and Large Survey • PAU (Physics of the Accelerating Universe): • Expected results: Benitez et al. 2009 Benitez et al. 2009

41. Deep and Large Survey • PAU (Physics of the Accelerating Universe): • Expected results: Benitez et al. 2009

42. Deep and Large Survey • PAU (Physics of the Accelerating Universe): • Comparison with other proposed BAO surveys: Benitez et al. 2009

43. Conclusions • General Relativity discovery and Cosmological Principle formulation give us New Cosmology theory and New Observables • New observables like Redshift require Deep Surveys to parametrize our univers and to study Dark Energy nature • BAOScale is a good Standar Ruler but its detection requires Large Surveys

44. Conclusions • Luminous Red Galaxies are good mass tracers to detect BAO • Photometric Redshift is the most optimum method to measure LRG redshifts • The PAU survey is relevant because it uses 42 filters that provide less than 0.003 redshift errors so, it can detect BAO in the line-of-sigth.