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Neutrinos and TeV photons from Soft Gamma Repeater giant
flares
Neutrino telescopes can be used as TeV detectors for short time scale events using s from
photoproduction in showers !Can AMANDA detect a signal from 27 Dec. giant flare
from SGR 1806-20 (above horizon)? In what channels?
• Review soft- and X-ray observations on SGR giant flares • A toy model based on Beppo-SAX SGR 1900-14 spectrum• Muon and Neutrino signals• Backgrounds• Useful information for the blind data analysis
Francis Halzen, Hagar Landsman, Teresa Montaruliastro-ph/0503348
LBL, IceCube Meeting, Mar. 2005
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What are SGR’s?
• X-ray stars emitting short (~100 ms) bursts in X/soft -ray typically of energy 1041 D10
2 ergs
• Steady X-ray emission with luminosities 1035-1036 D10
2 erg/s with OTTB+power law spectra E-(13)
• From slow down rate of steady emission period (5-8 s) huge magnetic fields B ~1014-1015 G
• Similar to 8 Anomalous X-ray Pulsars but typically these do not emit bursts (1 exception)
• 5 galactic except for SGR 0526-66 in LMC
http://solomon.as.utexas.edu/magnetar.htmlWoods & Thompson, astro-ph/0406133
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The Magnetar Model and emissionSteady X-ray emission powered by decay of n star magnetic field Luminosities 1035-1036 D10
2 erg/s periodic (5-8 s)
Neutrinos: Zhang et al ApJ 595 (2003)the potential drop through the magnetosphere of the rotating n star might accelerate protons above photomeson threshold (depends on n star period and B and geometrical factor) interaction on thermal radiation from heated n star surface
Rates strongly depend on beaming angle around polar axis
dN/dE E-2
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Why giant flares?
•3 ‘giant’ flares: VERY HARD component dN/dE E-1.5-1.7 (Cheng et al., Nature 1996)
•Dec. 27, 2004 peak lasting 0.25 s followed by a 300 s long tail with 7.57 s
period and -140 s precursor (INTEGRAL, GCN2920) following previous series of bursts: Dec 21 and Oct 5. Still active.
Rearrangements of magnetic field and formation and dissipation of strong localized currents. These may fracture the rigid crust that outbursts
Can be a process in which nucleons and nuclei are accelerated
Similar to small GRB’s: SGR giant flares are 106-7 less intense but d2 1010
Detected radio afterglows imply relativistic outflows + huge luminosities with barion loading fireball (Piran et al, astro-ph0502148, Ioka et al, astro-ph/0503279)
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Giant flare energy
Source SGR1900+14 (1998)
SGR1806-20 (2004)
Duration 0.35s 0.25 s
Fluence in initial pulse (ergs/cm2
)
>5.5·10-3 (Konus-Wind 15-250 keV)>6.4 10-4
(Beppo-SAX 40-700 keV)
2.4!!(GEOTAIL)>0.1 (RHESSI)Ge detectors up to 15 MeV saturated
No spectral measurement of the 1st s available. X-ray detectors suffered saturation effects. SGR 1900+14 AMANDA B-10
Beppo-SAX: Spectrum for first 68s up to 700keV (1s resolution)
SGR 1806-20 AMANDA-II (critical period) No spectrum available.
Similar flare. >2 orders of magnitude stronger
GEOTAIL (astro-ph/0502315) not saturated: measured fluence implies for d = 15 kpc a very efficient mechanism that releases ~1047 erg in 600 ms
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The SGR 1900-14 Aug 27, 1998 giant outburstBeppo-Sax (Feroci et al, 1999)
A) 0-67 sec 70-650 keV OTTB+PL E-1 exp(-E/31.2 keV)+E-1.47
B) 68-195 sec 70-400 keV OTTB E-1 exp(-E/34.2 keV) + E-4.5
C) 196-323 sec 70-400 keVOTTB E-1 exp(-E/28.9 keV)
E-1.47
Guidorzi et al, 2004: response function of GRBM was not well known at large off-axis angles 70-600 keV only and 10% sys error
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Spectrum Extrapolation at TeV energies
OTTB+PL fits
New best fit accounts better for the <60 keV region but for HE we use negative power law and vary it to account for the errors
Guidorzi private communication
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Muons from Gammas Competition of pion interaction and decay in the atmosphere
(Drees Halzen Hikasa, PRD39, 1989, Stanev Gaisser Halzen PRD32 1985):
AMANDA-II horizontal averaged area = 30000 m2 and 0.3 s
At South Pole: =-20˚ = 70˚
spectra
Pion photoproduction cross section in FLUKA
XN
energy to produce of energy E
E,th = 10 GeV
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Muon signal
But this particular flare was at 68˚ and Milagro analyses are commonly performed up to 45˚
astro-ph/01105131 Hz in 82 deg2 and 0.3 s at 5 km depth
0.86
Gamma showers in MILAGRO
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For a source below horizon as SGR1900+14But also horizontal muonsfrom neutrinos but 1/ 2.65
Upward-going muons and cascades in AMANDA
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Conclusions• We calculated possible muon and neutrino rates for Dec 27 giant
flare as a function of spectrum. AMANDA can constrain it !
• Relevant time scale of the order of 0.1 s and spatial constraint allow a search using downgoing muons
• We should use the neutrino cascade channel and look for neutrino induced muons
• We will preferably use IceTray or SIEGLINDE
• Start from raw data -> ROOT files