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Detection of Ultra High Energy (> 10 21 eV ) cosmic rays with LOFAR

Detection of Ultra High Energy (> 10 21 eV ) cosmic rays with LOFAR. Kalpana Singh, KVI, Groningen NuMoon Collaboration of LOFAR-CR 10 th Sept. 2008. Low flux (Detection Challange).

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Detection of Ultra High Energy (> 10 21 eV ) cosmic rays with LOFAR

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  1. Detection of Ultra High Energy (>1021 eV) cosmic rays with LOFAR Kalpana Singh, KVI, Groningen NuMoon Collaboration of LOFAR-CR 10th Sept. 2008 ECRS 2008

  2. Low flux (Detection Challange) GZK suppression : hadrons interact with cosmic microwave background and undergo pion photoproduction reaction, therefore loose on average 3 to 4 nucleons per 1 MPc. ECRS 2008

  3. Traditional Models of Accelerationand Sources • Colliding galaxies • Active Galactic Nuclei • Topological defects in early universe • Gravitational production of supermassive metastable particles • Protons with energy >GZK produce pions at collisions with relic photons, and these pions decay result in cosmogenic neutrino flux. Bottom up model Top Down model ECRS 2008

  4. Detection Methods • Cherenkov light produced in water or ice (ANTARES, IceCube and RICE – south pole and KM3NET - Mediterranean sea). • ANITA balloon mission. • FORTE satellite – Greenland. ECRS 2008

  5. Large Area ?? Use Moon  Area = 2 107 km2 ECRS 2008

  6. Super–GZK Neutrino Detection • Ultra high energy particle showers hitting the moon produce radio Cherenkov emission ( Zas, Gorham, ……) • This provides the largest and cleanest particle detector available for direct detections at the very high energies. • In the forward direction (Cherenkov cone) the maximum of the emission is in the GHz range. • Goldstone (GLUE - Moon). • LUNASKA at Australian Telescope Compact Array. • WSRT (radio Telescope – using lunar regolith) From Gorham et al. (2000) ECRS 2008

  7. Low frequency observation • Spreading of Cherenkov cone • Area of detection of Lunar surface increases Scholten et al. ECRS 2008

  8. Reflection • Spreading is diminishing internal reflection @ 100 MHz ECRS 2008

  9. Detection Sensitivity • Lower frequency  irregularity of moon surface is negligible compared to the wavelength. • With decreasing   • Increasing area • Increasing probability • Increasing threshold -1 • Increase Sensitivity -3 ECRS 2008

  10. CRs with LOFAR Flowchart of online processing Every dipole has a 1s “Transient Buffer” storing the full electro-magnetic wave information (all-sky, all-frequency)! Antenna fields 2 x 2 km2 core area LOFAR: ~14000 antenna will see one shower ECRS 2008

  11. Principle of the measurement Cosmic ray Detection: LOFAR antennas 107 km2 ~ 100MHz Radio waves ECRS 2008

  12. Detection limits for cosmic rays ECRS 2008

  13. Detection limits for neutrinos ECRS 2008

  14. Conclusions • LOFAR observations of lunar ns-pulses from the Moon give unrivalled sensitivity for super-GZK particles (>1021 eV). • Sensitive to both cosmic rays and neutrinos. • Within 100 days competitive. • We have enough experience with WSRT data. ECRS 2008

  15. Thanks !! NuMoon Collaboration of NuMoon-CR Andreas Horneffer, Heino Falcke, Kalpana Singh, Olaf Scolten, Lars bahren, Stijn Buitink ECRS 2008

  16. WSRT and SKA ECRS 2008 Scholten et al., ARENA 2008

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