Comparative study of the inial spikes of SGR giant flares in 1998 and 2004 observed with GEOTAIL: Do magnetospheric instabilities trigger large scale fracturing of magnetar's crust?

Details Comparative study of the inial spikes of SGR giant flares in 1998 and 2004 observed with GEOTAIL: Do magnetospheric instabilities trigger large scale fracturing of magnetar's crust? Comparative study of the inial spikes of SGR giant flares in 1998 and 2004 observed with GEOTAIL: Do magnetospheric instabilities trigger large scale fracturing of magnetar's crust?

2007-06-21

arxiv.org/abs/0706.3123v1

Astronomy and Astrophysics

Astrophysics

12 pages, 3 figures, accepted by ApJL

Scientific paper

10.1086/521025

We present the unsaturated peak profile of SGR 1900+14 giant flare on 1998 August 27. This was obtained by particle counters of the Low Energy Particle instrument onboard the GEOTAIL spacecraft. The observed peak profile revealed four characteristic structures: initial steep rise, intermediate rise to the peak, exponential decay and small hump in the decay phase. From this light curve, we found that the isotropic peak luminosity was $2.3\times10^{46}$ erg s$^{-1}$ and the total energy was $4.3 \times 10^{44}$ erg s$^{-1}$ ($E\gtrsim$ 50 keV), assuming that the distance to SGR 1900+14 is 15 kpc and that the spectrum is optically thin thermal bremsstrahlung with $kT =$ 240 keV. These are consistent with the previously reported lower limits derived from Ulysses and Konus-Wind observations. A comparative study of the initial spikes of SGR 1900+14 giant flare in 1998 and SGR 1806-20 in 2004 is also presented. The timescale of the initial steep rise shows the magnetospheric origin, while the timescale of the intermediate rise to the peak indicates that it originates from the crustal fracturing. Finally, we argue that the four structures and their corresponding timescales provide a clue to identify extragalactic SGR giant flares among short GRBs.

Affiliated with

Also associated with

No associations

Rating

Comparative study of the inial spikes of SGR giant flares in 1998 and 2004 observed with GEOTAIL: Do magnetospheric instabilities trigger large scale fracturing of magnetar's crust? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Comparative study of the inial spikes of SGR giant flares in 1998 and 2004 observed with GEOTAIL: Do magnetospheric instabilities trigger large scale fracturing of magnetar's crust?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Comparative study of the inial spikes of SGR giant flares in 1998 and 2004 observed with GEOTAIL: Do magnetospheric instabilities trigger large scale fracturing of magnetar's crust? will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-192595