Neutrinos as probes of ultra-high energy astrophysical phenomena

1. Neutrinos as probes of ultra-high energy astrophysical phenomena Jenni Adams, University of Canterbury, New Zealand

2. Neutrino sources 10-40 MeV GeV – 10sTeV up to 10 MeV J. Becker Phys. Rep. 458

3. How do we know there are high energy astrophysical phenomena? • Observe high energy particles • Observe radiation that is indicative of high energy processes • There might be hidden sources…

4. Cosmic messengers

5. Astroparticle physics Neutrino astrophysics astroparticle physics High energy photon astrophysics Cosmic ray astrophysics

6. Origin of the ultra-high energy cosmic rays? ?

7. How do we accelerate a particle? • Fermi Acceleration

8. How do we accelerate a tennis ball? • Not with a steady tennis racket!

9. Need a moving racket

11. Back to particles… ball ↔ charged particle racket ↔ magnetic mirror

12. Fermi Acceleration • 2nd Order: randomly distributed magnetic mirrors slow and inefficient • 1st Order: acceleration in strong shock waves

13. Hillas Plot What condition is used to estimate the maximum energy which can be obtained from a given site? The gyroradius is less than the linear size of the accelerator E18max=bsZBR

14. Auger sky map • At energies > 6 X 1019 eV can get indications of origin (why not at lower energies?) • significance reduced in larger data set…?

15. How do we know there are high energy astrophysical phenomena? • Observe high energy particles • Observe radiation that is indicative of high energy processes • There might be hidden sources…

16. Non-thermal radiation – what do we mean by non-thermal?

18. Nature’s accelerators

19. Information from Gamma-Rays • Lots of sources identified • Morphology of galactic sources resolved • but most sources can be described by leptonic models as well as hadronic

20. Why detect neutrinos? Source of the highest energy cosmic rays

21. Animation generated with povray Neutrino production • p + p or p +  give pions which give neutrinos eg. p +  + n/0 p • +  +  e+e  • 0  (E~TeV)

22. Why detect neutrinos? Figure: Wolfgang Wagner, PhD thesis

23. BL Lac Object Krawczynski et al., ApJ 601 (2004)

24. Accidentally discovered by the military Vela satellites in the late 1960’s = Short, intense, eruptions of high energy photons, with afterglow detected in X-ray to radio Isotropic distribution in the sky Bimodal distribution of burst times Non-thermal photon spectrum Energy output of 1051 erg to 1054 erg

25. Progenitors • Long duration bursts result from collapse of massive star to black hole • GRB030329 observed by HETE II linked to type 1C Supernova • Long duration bursts in galaxies with young massive stars • Short duration bursts result from collision of some combination of black holes and neutron stars • GRB050509B observed by Swift with limited afterglow • Appears to have occurred near a galaxy with old stars • Theories may be rewritten by Swift observations • 050502B X-ray spike after burst, indications of multiple explosions

26. Fireball Model Radiation dominated soup of leptons and photons implied by high optical depth Radiation pressure drives relativistic expansion of material outward M. Aloy et al. ApJL2000

27. Afterglow g-rays Inner Engine Relativistic Wind Internal Shocks External Shock But observed spectrum is non-thermal and significant energy is expected to be transferred to the baryonic content in the wind

28. Shock fronts Prompt g–ray emission produced by dissipation of fireball kinetic energy in internal shocks - supported by microstucture Afterglow produced in external shocks – softened spectrum due to decreasing Lorentz factor

29. Burst spectrum Band et al., ApJ 413 (1993)   = -0.968 ± 0.022   = -2.427 ± 0.07 b = 149.5 ± 2.1 keV b GRB1122

30. Burst spectrum Inverse Compton scattering or cooling of electrons at high energies  Synchrotron radiation from accelerated electrons   ~ - 1  ~ -2 b = 100 – 300 keV b

31. Example of neutrino spectrum for high energy astrophysical object – GRB n Spectrum

32. Neutrino production • p + p or p +  give pions which give neutrinos eg. p +  + n/0 p • +  +  e+e  • 0  (E~TeV)

33. Example of neutrino spectrum

34. GRB n Spectrum (II) • Highest energy pions lose energy via synchrotron emission before decaying reducing the energy of the decay neutrinos • Effect becomes important when the pion lifetime is comparable to the synchrotron loss time • Neutrino spectrum steepens by a power of two after this second break energy

35. bn an bn-2

36. fp: fraction of proton energy going into pions GRB n Spectrum (III) ax 50%charged pions, 25% per particle fe: fraction of electron to proton total energy

37. Animation generated with povray Neutrino production • p + p or p +  give pions which give neutrinos eg. p +  + n/0 p • +  +  e+e  • 0  (E~TeV)

38. Neutrino sources 10-40 MeV GeV – 10sTeV up to 10 MeV J. Becker Phys. Rep. 458

39. HE Neutrino probes of fundamental physics

40. in proportion Other neutrino detectors Super Kamiokande SNO

41. Neutrino telescopes around the globe Lake Baikal ANTARES NEMO NESTOR KM3NET DUMAND AMANDA, RICE, IceCube, ANITA

42. Muon – IC 40 data Topological Flavour Identification • nm produce long m tracks • Angular resolution ~ 10 • ne CC, nx NC cause showers • ~ point sources ->’cascades’ • Good energy resolution • nt ‘double bang events • Other nt topologies under study ne (cascade)simulation 16 PeV nt simulation

43. Neutrino-nucleon cross-section

44. Earth becomes opaque for neand nm note: angle from nadir

45. Coming to a cinema (conference, journal) near you soon… Neutrinos Astrophysical neutrinos caught