1. Cosmic Rays Liz Puchnarewicz Mullard Space Science Laboratory University College London www.mssl.ucl.ac.uk

2. What are they? photons = light packets atomic fragmen ts proton neutro n electro n ion …moving very fast!! atom

3. Stripping an atom

10. ion = “stripped” nucleus massive (compared to protons, neutrons and electrons. And photons) positively charged

11. Energizing to CRs photons mass-less, v=speed of light particles e -p+n Z+ light medium heavy … so need to accelerate particles to speeds close to the speed of light

12. Accelerating particles How are particles pushed to the speed of light? Slung out by the enormous gravitationa l potentials of black holes Thrown out by massive stellar explosions - supernova e Dragged out by intense electric and magnetic fields – eg in pulsars

13. hydrogen helium Supernovae silicon carbon helium iron

14. hydrogen helium Supernovae carbon silicon helium iron

15. Supernovae

18. Crab Nebula Hubble (red) and Chandra (blue) composite of the Crab Nebula. The progenitor star went supernova about 1000 years ago.

19. A cosmic blast wave M. DeBord, R. Ramaty and B. Kozlovsky (GSFC), R. Lingenfelter (UCSD), NASAGSFC NASA Atoms are torn from the brownish bands of dust by shock waves (represented by orange rings). The shocks in the expanding blast wave then accelerate the atoms to near light speeds firing them into interstellar space like cosmic bullets.

20. Supermassive black holes Black holes in quasars throw out particles at near- light speeds and produce high-E photons

21. Pulsars Light cylinder Open magnetosphere r=c/  B Closed magnetosphere Neutron star mass = 1.4 solar masses radius = 10 km B = 10 to 10 Tesla 49

22. Pulsars – the movie

23. A bit of history First discovered during high altitude balloon flights by Victor Hess 1912 Pierre Auger discovered extensive air showers 1938 Enrico Fermi proposed cosmic ray shock accelerators 1949 GZK cutoff proposed1966 Highest energy cosmic ray ever (3x10 20 eV) observed by the Fly’s Eye 1991

24. Air showers 00    e-e- e+e+

25. Cerenkov radiation

26. Whipple Next generation is VERITAS = 7 Whipple array 10m  -ray telescope – Cerenkov radiation detector 248 mirrors Largest and most sensitive - so far

27. The cosmic ray leg Below the knee – Milky Way sources (supernovae, pulsars) Knee to ankle – Galaxies and quasars Ankle - ??

28. Fly’s Eye

29. EUSO ESA mission - planned for launch 2009 Observes fluoresence in Earth’s atmospher e

30. OWL Orbiting Wide-angle Light-collectors

31. Nightglow

32. Global warming by cosmic rays not many cosmic rays lots of cosmic rays

33. The End For more information, visit: http://www.sciencedaily.com/releases/2002/0 7/020731080631.htm http://antwrp.gsfc.nasa.gov/apod/ap980618.ht ml http://www.auger.org/