cosmic rays and gamma ray bursts (grb’s)
DESCRIPTION
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 PresentationTRANSCRIPT
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
Gamma Rays and the Ionosphere
Solar ionization disappears at night Recombination rates on the order of ms Nighttime density maintained by cosmic ray flux
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
Gamma-ray waveform
Broad variety of durations and shapes
Gamma-ray burst on the ionosphere
From Fishman et al. 1988
Massive gamma-ray burst
From Inan et al. 2007
Second timescale characteristics
From Inan et al. 2007
-25 dB disturbance!!
From Inan et al. 2007
Minutes timescale characteristic
From Inan et al. 1988
Slow recovery
Hour timescale characteristic
From Inan et al. 2007
Recovery lasts for over 1 hour!
ELF emissions generated
From Inan et al. 2007
Mechanism for ELF emissions in question….
GRBs/SGRs and VLF sensing
VLF remote sensing of D-region ionosphere
GRBs repeatedly disturb ionosphere
NLK: 16-hour observationsLargest disturbances
NLK: most spectacular cases
SGR-Illuminated hemisphere
January 22nd, 2009, 6:48 UT Calculated using http://home.att.net/~srschmitt/script_celestial2horizon.html
Sunrise position
0250 UT
0650 UT
1050 UT