Testing cosmological models with the Integrated Sachs-Wolfe effect

1. Testing cosmological models with the Integrated Sachs-Wolfe effect Alvise Raccanelli, Institute of Cosmology and Gravitation, Portsmouth

2. Outline: • The standard model of cosmology • CMB anisotropies • The ISW effect • Why the ISW is a good test for cosmological models • Results and ongoing projects 2 Testing cosmological models with the ISW Alvise Raccanelli

3. Observations of Supernovae Type Ia told us that the universe is accelerating 3 Testing cosmological models with the ISW Alvise Raccanelli

4. The Universe is accelerating; this is caused by something different from the usual gravity 4 Testing cosmological models with the ISW Alvise Raccanelli

5. 5 Testing cosmological models with the ISW Alvise Raccanelli

6. After the Big Bang, the Universe was hot and dense, and photons were strongly coupled to electrons and protons Hu & White 2004 6 Testing cosmological models with the ISW Alvise Raccanelli

7. The Universe is hot and dense Before the recombination, photons are coupled with matter, so they can not travel to us 7 Testing cosmological models with the ISW Alvise Raccanelli

8. The Universe become colder and less dense, and at one point protons and electrons form hydrogen (recombination) After the recombination, photons are free to travel towards us 8 Testing cosmological models with the ISW Alvise Raccanelli

9. The Last Scattering Surace: why CMB is important 9 Testing cosmological models with the ISW Alvise Raccanelli

10. CMB Experiments 10 Testing cosmological models with the ISW Alvise Raccanelli

11. WMAP Planck 11 Testing cosmological models with the ISW Alvise Raccanelli

12. The Planck First Light 12 Testing cosmological models with the ISW Alvise Raccanelli

13. Better Power Spectrum at small scale The Planck BlueBook 2005 13 Testing cosmological models with the ISW Alvise Raccanelli

14. 14 Testing cosmological models with the ISW Alvise Raccanelli

15. ISW effect: evolving gravitational potential 15 Testing cosmological models with the ISW Alvise Raccanelli

16. Galaxies form inside gravitaional wells left after inflation 16 Testing cosmological models with the ISW Alvise Raccanelli

17. Travelling from the last scattering surface to us, photons pass through gravitational wells. If the potential is static, they will exit with the same energy they had when they entered. If the well is stretched by the dark energy, photons will experience a shift in energy (and so in temperature) 17 Testing cosmological models with the ISW Alvise Raccanelli

18. But this effect is small compared to other CMB anisotropies 18 Testing cosmological models with the ISW Alvise Raccanelli

19. so we need to cross-correlate this temperature shift with something that can trace potential wells. Galaxies are a biased tracer of potential wells 19 Testing cosmological models with the ISW Alvise Raccanelli

20. 20 Testing cosmological models with the ISW Alvise Raccanelli

21. This part tells us where is matter 21 Testing cosmological models with the ISW Alvise Raccanelli

22. This part tells us how the gravitational potential change 22 Testing cosmological models with the ISW Alvise Raccanelli

23. ISW can be used to test the gravitational or the galaxies part: • Changing the filter of the galaxies allow to test models for the bias relating the visible matter to the mass (including Dark Matter) and the redshift distribution of galaxies • Changing the filter of the gravitational part allow to test models of gravity 23 Testing cosmological models with the ISW Alvise Raccanelli

24. Results: Testing Galaxy distribution and bias models Work with G. De Zotti, S. Matarrese, M. Negrello, A. Bonaldi, G. Tormen Raccanelli et al. 08 24 Testing cosmological models with the ISW Alvise Raccanelli

25. Results: Testing new Galaxy distribution models Work with G. De Zotti, M. Massardi, M. Negrello, A. Bonaldi, S. Ricciardi Massardi et al. 10 25 Testing cosmological models with the ISW Alvise Raccanelli

26. Ongoing projects: • Test of Unified Dark Matter models • (with D. Bertacca, D. Pietrobon, S. Matarrese, T. Giannantonio, N. Bartolo, O. Piattella) • ISW with LOFAR data • (with W. Percival, M. Jarvis, D. Bacon, S. Rawlings, F. Abdalla) • Test of Modified Gravity Models • (with F.P. Silva, K. Koyama, T. Giannantonio, G.-B. Zhao) 26 Testing cosmological models with the ISW Alvise Raccanelli

27. Preliminary results for testing UDM models Bertacca et al., in preparation 27 Testing cosmological models with the ISW Alvise Raccanelli

28. In some modified gravity scenarios we expect a negative cross-correlation, due to the “stronger” dark energy Kobayashi et al. 09 28 Testing cosmological models with the ISW Alvise Raccanelli

29. Conclusions • The ISW is a good test for testing different cosmologies • The incoming data from CMB and Large Scale Structure observations will allow a better estimation of cosmological parameters 29 Testing cosmological models with the ISW Alvise Raccanelli