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Cosmic rays and Gamma Ray Bursts (GRB’s)

Cosmic rays and Gamma Ray Bursts (GRB’s). Prepared by Brant Carlson, Morris Cohen, and Benjamin Cotts Stanford University, Stanford, CA IHY Workshop on Advancing VLF through the Global AWESOME Network. Gamma Rays and the Ionosphere. Solar ionization disappears at night

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Cosmic rays and Gamma Ray Bursts (GRB’s)

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  1. Cosmic rays and Gamma Ray Bursts (GRB’s) Prepared by Brant Carlson, Morris Cohen, and Benjamin Cotts Stanford University, Stanford, CA IHY Workshop on Advancing VLF through the Global AWESOME Network

  2. Gamma Rays and the Ionosphere • Solar ionization disappears at night • Recombination rates on the order of ms • Nighttime density maintained by cosmic ray flux

  3. Gamma-ray bursts • Associated with very energetic explosions • Collapsing star • Supernova formation • Typically lasts a few ms to several minutes • Accidentally discovered by Vela-3 spacecraft in 1967

  4. Gamma-ray waveform • Broad variety of durations and shapes

  5. Gamma-ray burst on the ionosphere From Fishman et al. 1988

  6. Massive gamma-ray burst From Inan et al. 2007

  7. Second timescale characteristics -25 dB disturbance!! From Inan et al. 2007 From Inan et al. 2007

  8. Minutes timescale characteristic Slow recovery From Inan et al. 1988

  9. Hour timescale characteristic Recovery lasts for over 1 hour! From Inan et al. 2007

  10. ELF emissions generated Mechanism for ELF emissions in question…. From Inan et al. 2007

  11. GRBs/SGRs and VLF sensing • VLF remote sensing of D-region ionosphere • GRBs repeatedly disturb ionosphere

  12. NLK: 16-hour observations Largest disturbances

  13. NLK: most spectacular cases

  14. SGR-Illuminated hemisphere January 22nd, 2009, 6:48 UT Calculated using http://home.att.net/~srschmitt/script_celestial2horizon.html

  15. Sunrise position 0250 UT 0650 UT 1050 UT

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