PowerPoint Presentation - Acceleration of Cosmic Rays at Large Scale Shocks and their Implication for Structure Formation

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Elusive Intergalactic Magnetic Fields and their
Impact on UHECRs Propagation
F. Miniati ETH, Zuerich March 14 2005, LaThuile
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Outline

• Intergalactic magnetic fields
• Deflections of UHECRs
• low-frequency radio ?-ray observations

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2dFGalaxy Redshift Survey 2003
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Press-Schechter ?m 0.3 ?? 0.7 h 0.7
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Cen Ostriker 1999
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Faraday Rotation Measure
? QSO
B
los
?
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Intra-cluster medium
Miniati, Kronberg, Boehringer, Dufton in prep.

Clarke, Kronberg Boehringer 2001 Hollit et al.
2005
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Intergalactic medium (filaments sheets of
matter)
Kronberg 1994
Ryu, Kang Biermann 1998
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Sigl, Miniati Ensslin 2003
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Sigl, Miniati Ensslin 2004
Armengaud, Sigl Miniati 2005
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A3667 1.4GHz _at_ATCA ROSAT PSPC
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Cosmic shocks
Miniati (2003, MNRAS)
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(Di Matteo, Ciardi Miniati 2004)
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?-ray F(gt100 MeV)
Hard X-ray F(gt100 keV)
Thermal X-ray
Miniati 2003, MNRAS 342, 1009
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Miniati 2002, MNRAS 377, 199
Upper limits from EGRET experiment (Sreekumar et
al. 1996 Reimer et al. 2004)
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Conclusions

• Intergalactic magnetic fields are unknown
• Deflections of UHECRs cannot be constrained in
  any
• compelling way, based on current observations
• Combined high sensitivity low-frequency radio
  and ?-ray observations will allow important
  progress on the subject