1. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Testing Dark Energy with Supernovae Supernova 1994D Marek Kowalski Universität Bonn, PI Physikalisches Kolloquium Bonn, 23.10.2009

2. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Content  Introduction: the accelerating Universe  SNe observations & cosmological parameters  Constraints on selected Dark Energy models

3. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Content  Introduction: the accelerating Universe  SNe observations & cosmological parameters  Constraints on selected Dark Energy models

4. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Our Cosmological Framework derives from… Observation: The Universe is expanding Principles: Homogeneous, isotropic Theory: General Relativity Matter Density Cosmological Constant/ Dark Energy Curvature  Friedman Equation, which governs expansion

5. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Our Cosmological Framework derives from… Observation: The Universe is expanding Principles: Homogeneous, isotropic Theory: General Relativity  Friedman Equation, which governs expansion

6. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Our Cosmological Framework derives from… Observation: The Universe is expanding Principles: Homogeneous, isotropic Theory: General Relativity Matter Density  Friedman Equation, which governs expansion

7. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Our Cosmological Framework derives from… Observation: The Universe is expanding Principles: Homogeneous, isotropic Theory: General Relativity Matter Density Cosmological Constant/ Dark Energy  Friedman Equation, which governs expansion

8. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Our Cosmological Framework derives from… Observation: The Universe is expanding Principles: Homogeneous, isotropic Theory: General Relativity Matter Density Cosmological Constant/ Dark Energy Curvature  Friedman Equation, which governs expansion

9. 1998: Discovery of Dark Energy  MM

10. MM   Weak lensing mass census  Large scale structure  Baryon Accoustic Oscillations  M = 0.3 Flat universe   +  M = 1.01+/-0.02 1998: Discovery of Dark Energy

11. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 WMAP 2006

12. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 FlatΩ k =0 OpenΩ k <0  ≈1°  <1° Acustic horizon  v s t dec Closed Ω k >0  >1° Cosmic Microwave Background (CMB) & Curvature of the Universe

13. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 SDSS, Eisenstein et al. (2005) Baryon Acoustic Oscillation (BAO)

14. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 3

15. 3 Dark Energy 72%

16. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Vacuum Energy Ground-state of a scalar quantum field: Casimir effect  Energy difference Vacuum energy density: (with cut-off k max )

17. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Vakuum energy: Before: E = 0 After: Ax  >0 Pressure (p) of Vacuum energy follows from energy conservation: Ax  +Axp = 0  p = -   x A Vacuum energy has all the properties of the Cosmological constant , i.e. it has negative pressure. Vacuum Energy  Cosmological Constant Zeldovich 1968

18. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Fundamental Problems of Vacuum Energy/Cosmological Constant: Why so small? Expectation:    planck ) 4  120 orders of magnitudes larger then the observed value! Why now? Matter:  R -3 Vakuum Energy:  = constant Dark Energy with equation-of-state: p=w  (p = pressure;  = density)  R -3(1+w)

19. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Equation of state: w=p/  A few examples: w M = 0 (matter) w R = 1/3 (radiation) w  = -1 (cosmological constant) w Q > -1 (quintessence) w s = -1/3 (cosmic strings)

20. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Content  Introduction: the accelerating Universe  SNe observations&cosmological parameters  Constraints on selected Dark Energy models

21. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 ` Perlmutter & Schmitt 2003 11

22. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009  White dwarf in binary system  Mass transfer up to „critical“ Chandrasekhar mass of 1.4 M   Thermonuclear explosion  Explosion of similar energies  Visible in cosmic distances Supernova Type Ia

23. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Astronomers think in… Magnitudes: m = -2.5 log(Flux) + constant Filter: B,V,R,I,Z (400-900 nm)

24. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 “Standard candles“ Brightness not the same for all SNe „Stretching“ of time scale: Brightness correction: Brighter SNe have wider light curves.

25. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Spectra for identification and redshift determination

26. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 SNe Ia Hubble Diagram normalization fainter then expected     M 1 0 0.72 0.28 0 1 A bit brighter   M fainter Supernova Cosmology Project (SCP) Kowalski et al. (2008)

27. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 New in Bonn… Supernova Factory Collaboration: Lawrence Berkeley National Lab Laboratorie de Physique Nucleaire et de Haute Energies de Paris Institut de Physique Nucleaire de Lyon Centre de Recherche Astronomy de Lyon Yale University Bonn University

28. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 SNfactory: producing unique nearby SNe data 1. Discover

29. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 SNfactory: producing unique nearby SNe data 1. Discover 2. Observe SNIFS: Custom spectrograph for nearby SN observations

30. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 SNfactory: producing unique nearby SNe data 1. Discover 2. Observe 3. Analyses SNIFS: Custom spectrograph for nearby SN observations

31. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 SuperNova Integral Field Spectrograph (SNIFS) 12 Acquisition, Guiding Microlens array to two channel spectrograph 15x15 = 225 spectra Extinction monitoring, calibration Photometric Channel 6” x 6” FOV; 0.4”/spaxel 9.4’ x 9.4’ FOV; 0.14”/pix Pick-off Prism at SN loc Galaxy + Sky SN + Galaxy + Sky Sky SN

32. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 33 Slides: Rui Pereira Spectrophotometry synthetic photometry of SN2005el From Spectra to Lightcurves

33. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Slides: Rui Pereira Spectrophotometry synthetic photometry of SN2005el One spectrum per point / night Synthesizable in any filter Lightcurves + spectral features From Spectra to Lightcurves

34. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 The Union SNe Compilation    M 1 0 0.72 0.28 0 1 fainter

35. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 A heterogenous data sample

36. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Study of - mean deviation -... A heterogenous data sample

37. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Test for Tension high-z low-z mean deviation: OK

38. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Perlmutter et al., 1999 Results: Cosmological Parameters  MM  MM Kowalski et al., 2008

39. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Perlmutter et al., 1999   Kowalski et al., 2008 Results Cosmological Parameters Combination of SNe with: BAO (Eisenstein et. al., 2005) CMB (WMAP-5 year data, 2008) For a flat Universe: … and with curvature: MM

40. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Equation of state: w=p/ 

41. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Content  Introduction: the accelerating Universe  SNe observations&cosmological parameters  Constraints on selected Dark Energy models

42. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Many models to explain cosmic acceleration exist … but none without difficulties. Menu of possibilities: 1.Quantum Vakuum Energy (static) + it exists! - 60-120 orders of magnitude to large 2.Quintessence (dynamic) + Solves „why now“ problem, connects to inflation? - „smallness“ problem persists, small coupling 3.Modification of gravity (hence, no dark energy) + no Dark Energy - Gravitation in solar system well understood

43. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Braneworld Cosmology Large extra dimensions can solve the hierarchy problem of particle physics… (e.g. unification of forces) Randall & Sundrum Arkani-Hamed, Dimopoulos, Dvali …and will weaken Gravity at large distances (Dvali, Gabadadze, Porrati - DGP)  apparent acceleration

44. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 DGP-model versus  CDM Without systematic:   2 stat = 16.1 With systematic:   2 sys = 4.0 D. Rubin, E. Linder, MK, et al, 2009 Braneworld Cosmology

45. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 - ln(1+z) m Quintessence Example: Growing Neutrinos C. Wetterich (2007), L. Amendola et al. (2007), Scalar field couples to massive neutrinos Once neutrinos become sub-relativistic, one obtains  -like behavior. Today: Massive neutrinos and deviation from w =-1

46. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 D.Rubin, E. Linder, MK et al., (2009) Early dark energy  e m <1.2 (h/0.7) 2 eV @ 95 CL stat error only m <2.1 (h/0.7) 2 eV @ 95 CL with sys error with sys error 33 22 11 Lab constraints: m  2 eV Katrin sensitivity: m    0.2 eV  oszillations: m  0.05 eV Quintessence Example: Growing Neutrinos

47. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Future projects for Dark Energy Projekt z range # SNe Pan-STARRS 0.1-0.5 ~10 4 DES (2011) 0.2-0.7 ~2x10 3 LSST (2015) 0.1-0.9 ~10 6 SNAP (2017) 0.2-3.0 ~3x10 3 (JDEM/Euclid) SNAP Other important future methods: Weak lensing Cluster rates Baryon acoustic osciallation

48. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Conclusion The observed acceleration of the Universe poses one of the most fundamental problems in physics today. So far everything looks consistent with cosmological constant. Detailed measurement of the dynamics can give insights into the acceleration meachanisms.

49. Ende

50. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Cosmic Microwave Background (CMB) & Curvature of the Universe WMAP Power spectrum as a function of angular scale: Expand the temperature map with spherical harmonics: Resonance length  acustict horizon

51. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Quintessence Skalare Field  with potential V(  ) (similar Inflaton) Bei geeignetem Potential folgt die Energiedichte dank „Hubble-Reibung” der Materiedichte (tracker-behavior).  Teilweise Lösung des „Warum jetzt“ Problems. Wetterich (1987) Friedmann-Gleichung für  :

52. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Testing SN evolution by subdividing the sample Evolution test: Redshift No significant evidence for evolution! Evolution test: Population luminosity-width correction coefficient luminosity-color correction coefficient

53. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Redshift dependent w Assuming step-wise constant w: A floating non-SNe bin to decouple low from high-redshift constraints

54. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Dark Energy: 65% Dark Matter: 30% 70% 25% 95% of the Universe is unknown!

55. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 What’s wrong with a Vacuum Energy/Cosmological constant?

56. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 What’s wrong with a Vacuum Energy/Cosmological constant?

57. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 What’s wrong with a Vacuum Energy/Cosmological constant?

58. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Equation of state: w=p/  A few examples: w M = 0 (Matter) w R = 1/3 (Radiation) w  = -1 (Cosmological Constant) w Q > -1 (Quintessence) w s = -1/3 (Cosmic strings)

59. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Content  Introduction to supernova cosmology  SNe observations & cosmological parameters  Constraints on selected Dark Energy models

60. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Test for Tension high-z low-z residual slope: (OK)

61. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Supernova-Observations Reference new image difference Search for SNe with redshift z<1 e.g. SuperNova Legacy Survey (SNLS) with the CFH-telescope (3.6 meter). Every 3 days observation of the same part of the sky:  80 SNe / yr MegaCam: 340M pixel, 1  x1  field-of-view SN-candidate 14

62. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Perlmutter et al., 1999 Results: Cosmological fit parameters MM  MM Combination of SNe with: BAO (Eisenstein et. al., 2005) CMB (WMAP-5 year data, 2008) For a flat Universe: … and with curvature:

63. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 SNe at z>1 Observations with HST to obtain light curves in the near IR

64. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 SNIFS - Supernova Integral Field Spectrograph Synthetic photometry for any filter from galaxy subtracted spectra Telescope focal surface Spectrograph input Spectrograph output Lenslets 3D data cube Spectral Time Series

65. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 A heterogenous data sample

66. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Study of - mean deviation - residual slope A heterogenous data sample

67. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Test for Tension high-z low-z mean deviation: OK

68. Marek Kowalski Testing Dark Energy with Supernovae Bonn, 23.10.2009 Test for Tension high-z low-z residual slope: (OK)