cosmic rays and gamma ray bursts (grb’s)

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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

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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 - PowerPoint PPT Presentation

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Page 1: Cosmic rays and  Gamma Ray Bursts (GRB’s)

Cosmic rays and Gamma Ray Bursts (GRB’s)

Prepared by Brant Carlson, Morris Cohen, and Benjamin CottsStanford University, Stanford, CA

IHY Workshop on Advancing VLF through the Global AWESOME Network

Page 2: Cosmic rays and  Gamma Ray Bursts (GRB’s)
Page 3: Cosmic rays and  Gamma Ray Bursts (GRB’s)
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Gamma Rays and the Ionosphere

Solar ionization disappears at night Recombination rates on the order of ms Nighttime density maintained by cosmic ray flux

Page 13: Cosmic rays and  Gamma Ray Bursts (GRB’s)

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

Page 14: Cosmic rays and  Gamma Ray Bursts (GRB’s)

Gamma-ray waveform

Broad variety of durations and shapes

Page 15: Cosmic rays and  Gamma Ray Bursts (GRB’s)

Gamma-ray burst on the ionosphere

From Fishman et al. 1988

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Massive gamma-ray burst

From Inan et al. 2007

Page 17: Cosmic rays and  Gamma Ray Bursts (GRB’s)

Second timescale characteristics

From Inan et al. 2007

-25 dB disturbance!!

From Inan et al. 2007

Page 18: Cosmic rays and  Gamma Ray Bursts (GRB’s)

Minutes timescale characteristic

From Inan et al. 1988

Slow recovery

Page 19: Cosmic rays and  Gamma Ray Bursts (GRB’s)

Hour timescale characteristic

From Inan et al. 2007

Recovery lasts for over 1 hour!

Page 20: Cosmic rays and  Gamma Ray Bursts (GRB’s)

ELF emissions generated

From Inan et al. 2007

Mechanism for ELF emissions in question….

Page 21: Cosmic rays and  Gamma Ray Bursts (GRB’s)

GRBs/SGRs and VLF sensing

VLF remote sensing of D-region ionosphere

GRBs repeatedly disturb ionosphere

Page 22: Cosmic rays and  Gamma Ray Bursts (GRB’s)

NLK: 16-hour observationsLargest disturbances

Page 23: Cosmic rays and  Gamma Ray Bursts (GRB’s)

NLK: most spectacular cases

Page 24: Cosmic rays and  Gamma Ray Bursts (GRB’s)

SGR-Illuminated hemisphere

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

Page 25: Cosmic rays and  Gamma Ray Bursts (GRB’s)

Sunrise position

0250 UT

0650 UT

1050 UT