1. Marek Kowalski 11.5.2009 PTF, Szczecin Exploding Stars, Cosmic Acceleration and Dark Energy Supernova 1994D Marek Kowalski Humboldt-Universität zu Berlin Szczecin, 11.5.2009

2. Marek Kowalski 11.5.2009 PTF, Szczecin Outline  A brief history of Cosmology  Supernova observations today  A mysteries: Dark Energy 3

3. Marek Kowalski 11.5.2009 PTF, Szczecin Outline  A brief history of Cosmology  Supernova observations today  A mysteries: Dark Energy 3

4. Marek Kowalski 11.5.2009 PTF, Szczecin History Einstein, 1916: General Relativity

5. Marek Kowalski 11.5.2009 PTF, Szczecin History EnergyCurvature Einstein, 1916: General Relativity

6. Marek Kowalski 11.5.2009 PTF, Szczecin General Relativity: Gravitational bending of light

7. Marek Kowalski 11.5.2009 PTF, Szczecin General Relativity: Gravitational bending of light Abell 2218: A Galaxy Cluster Lens, Andrew Fruchter et al. (HST)

8. Marek Kowalski 11.5.2009 PTF, Szczecin General Relativity: The Universe can have curvature

9. Marek Kowalski 11.5.2009 PTF, Szczecin Einstein, 1916: General Relativity Curvature I want a static Universe - I’ll add a cosmological constant Energy

10. Marek Kowalski 11.5.2009 PTF, Szczecin Einstein, 1916: General Relativity History continues...

11. Marek Kowalski 11.5.2009 PTF, Szczecin History continues... Edwin Hubble, 1929: Redshift of Galaxies

12. Marek Kowalski 11.5.2009 PTF, Szczecin Redshift of spectral lines: “Doppler effect” The larger the distance to a Galaxy, the faster it is flying away from us: velocity = H 0 x distance

13. Marek Kowalski 11.5.2009 PTF, Szczecin Hubble: The Universe is expanding! Einstein: The cosmological constant was the biggest Blunder of my life!

14. Marek Kowalski 11.5.2009 PTF, Szczecin History continues... Edwin Hubble, 1929: Redshift of Galaxies

15. Marek Kowalski 11.5.2009 PTF, Szczecin 10 years ago: Detection of the accelerated Universe by two teams of astronomers History continues... The cosmological constant might be back! B. Schmidt S. Perlmutter

16. Marek Kowalski 11.5.2009 PTF, Szczecin

17. Marek Kowalski 11.5.2009 PTF, Szczecin Outline  A brief history of Cosmology  Supernova observations today  A mysteries: Dark Energy 3

18. Marek Kowalski 11.5.2009 PTF, Szczecin

19. Marek Kowalski 11.5.2009 PTF, Szczecin 1 Supernova Type Ia Type Ia supernovae (SNe Ia) provide bright “standard candle” that can be used to construct a Hubble diagram. Accretion sends mass of white dwarf star to Chandrasekhar limit leading to gravitational collapse and a thermo-nuclear explosion of its outer layers. Each one is a strikingly similar explosion event with nearly the same peak intensity.

20. Marek Kowalski 11.5.2009 PTF, Szczecin “Standard” Candles Nearby supernovae used to study SNe light curve (z<0.1) Brightness not quite standard Stretching the timescale: Correcting the Brightness: Intrinsically brighter SNe have wider lightcurves.

21. Marek Kowalski 11.5.2009 PTF, Szczecin Spectra used for Identification & Redshift determination

22. Marek Kowalski 11.5.2009 PTF, Szczecin Searching for Supernovae Reference new picture difference SN-Candidate For example with the: Canadian-French-Hawaii Telescope: 3.6 m MegaCam Camera: 3.6 10 8 pixels

23. Marek Kowalski 11.5.2009 PTF, Szczecin Sloan Digital Sky Survey

24. Marek Kowalski 11.5.2009 PTF, Szczecin SNe at large Redshifts (z>1) Observations from Space with the Hubble Space Telescopes: 15

25. Marek Kowalski 11.5.2009 PTF, Szczecin SNe Type Ia & Acceleration of the Universe Normalization fainter then expected     M 1 0 0.73 0.27 0 1 slightly brighter   M fainter Supernova Cosmology Project Kowalski et al., Ap.J. (2008)

26. Marek Kowalski 11.5.2009 PTF, Szczecin 18 Perlmutter et al., 1999 Cosmological Parameter  MM SNe + BAO + CMB Curvature: CMB: Komatsu et al. 2008 BAO: Eisenstein et al., 2005  MM Kowalski et al., 2008 Marek Kowalski 7. Juli 2008

27. Dark Energy: 65% Dark Matter: 30% 70% 25%

28. Marek Kowalski 11.5.2009 PTF, Szczecin Outline  Introduction to Supernova Cosmology  Supernova observations today  A mystery: Dark Energy 3

29. Marek Kowalski 11.5.2009 PTF, Szczecin Is Dark Energy a property of the Vacuum? Ground-state of a scalar Quantum-field: Vacuum-Energy density: (with ultraviolet Cut-off k max ) Casimir-Effekt  Energiedifferenz

30. Marek Kowalski 11.5.2009 PTF, Szczecin Vakuum energy: Before: E = 0 After: Ax  >0 Pressure (p) of Vacuum energy follows with assumption of energy conservation: Ax  +Axp = 0  p = -   x A Is Dark Energy a property of the Vacuum? Vacuum energy has all the properties of the Cosmological constant , it has negative pressure and hence can lead to acceleration of Universe.

31. Marek Kowalski 11.5.2009 PTF, Szczecin Fundamental Problems of Vakuum Energy/Cosmological Constante: Why so small? Expectation:    planck ) 4  120 orders of magntides to larger then the observed value! Why now? Matter:   R -3 Vakuum Energy:   konstant New Physics: Quintessence fields Extra dimensions Modification of Gravity … More data will hopefully tell us!

32. Marek Kowalski 11.5.2009 PTF, Szczecin Future projects in SN Cosmology Projekt z-Range # SNe Pan-STARRS 0.1-0.5 ~10 4 LSST (2015) 0.1-0.9 ~10 6 SNAP (2017) 0.2-3.0 >3000 (JDEM/Euclid) SNAP 20

33. Marek Kowalski 11.5.2009 PTF, Szczecin Conclusion 3/4 of the energy budget of the Universe consists of Dark Energy It looks like a cosmological constant / vacuum energy - but this interpretation has problems Next generation telescopes will produce unprecedented cosmological observations, and perhaps provide an answer

34. Ende

35. Marek Kowalski 11.5.2009 PTF, Szczecin Back Up

36. Marek Kowalski 11.5.2009 PTF, Szczecin Beobachtete Energiedichten Erwartete Energiedichten: Gravitation: SUSY: Electroweak: Fundamentale Probleme mit der Vakuum-Energie/Kosmologischen Konstante:

37. Marek Kowalski 11.5.2009 PTF, Szczecin Zustandsgleichung: w =p/  19

38. Marek Kowalski 11.5.2009 PTF, Szczecin Zustandsgleichung: w =p/  SNe + BAO + CMB 19 cosmological constant

39. Marek Kowalski 11.5.2009 PTF, Szczecin heterogener Datensatz

40. Marek Kowalski 11.5.2009 PTF, Szczecin Study of - mean deviation - residual slope A heterogenous data sample

41. Marek Kowalski 11.5.2009 PTF, Szczecin Test for Tension high-z low-z mean deviation: OK

42. Marek Kowalski 11.5.2009 PTF, Szczecin Test for Tension high-z low-z residual slope: (OK)