Changeset 6587
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- 02/18/05 11:24:10 (20 years ago)
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trunk/MagicSoft/GRB-Proposal/Introduction.tex (modified) (3 diffs)
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trunk/MagicSoft/GRB-Proposal/Introduction.tex
r6550 r6587 19 19 \par 20 20 21 Many publications foresee that high-energy $\gamma$-rays can come along with the 22 (low-energy) GRB. Possible causes range from proton-synchrotron emission~\cite{TOTANI} to 23 photon-pion production~\cite{WAXMAN,BOETTCHER} to inverse-Compton scattering 21 Possible causes range from proton-synchrotron emission~\cite{TOTANI} to 22 photon-pion production~\cite{WAXMAN,BOETTCHER} and inverse-Compton scattering 24 23 in the burst environment~\cite{MESZAROS93,CHIANG,PILLA,ZHANG2,BELOBORODOV}. 25 A long-term high energy (HE) $\gamma$-emission can come from accelerated protons in the 26 forward-shock, as predicted in~\cite{LI}. 27 This model predicts GeV inverse Compton emission even one day after the burst. 28 Even considering pure electron-synchrotron radiation, measurable GeV-emission for a significant 29 fraction of GRBs is predicted~\cite{ZHANG2}.\\ 30 31 GeV-emission in GRBs is particularly sensitive to the Lorentz factor and the photon density of the 32 emitting material -- 33 and thus to the distance of the radiating shock from the source -- due to the 34 $\gamma \gamma \rightarrow \textrm{e}^+\textrm{e}^-$ absorption in the emission region. 35 Direct comparison of the prompt GRB flux at $\sim$\,10\,GeV and $\sim$\,100\,keV may 36 allow to determine the magnetic field strength~\cite{ASAF2}. 24 A long-term high energy (HE) $\gamma$-emission can come from accelerated protons in the forward-shock, as predicted in~\cite{LI}. 25 This model predicts GeV inverse Compton emission up to one day after the burst. 26 Even considering pure electron-synchrotron radiation, measurable GeV-emission for a significant 27 fraction of GRBs is predicted~\cite{ZHANG2}. 37 28 38 29 \par 39 30 31 GeV-emission in GRBs is particularly sensitive to the Lorentz factor and the photon density of the emitting material -- and thus to the distance of the radiating shock from the source -- due to the $\gamma \gamma \rightarrow \textrm{e}^+\textrm{e}^-$ absorption in the emission region. Direct comparison of the prompt GRB flux at $\sim$\,10\,GeV and $\sim$\,100\,keV may allow to determine the magnetic field strength~\cite{ASAF2}.\\ 32 33 40 34 Several attempts were made in the past to observe GRBs in the GeV range, 41 35 each indicating some excess over background but without stringent evidence. 42 The only significant detection was performed by \eg, that was able to observe seven GRBs 43 emitting HE photons with energies between 100\,MeV and 18\,GeV~\cite{EGRET, DINGUS1}. 44 The data shows no evidence of a HE cut-off in the GRB spectrum~\cite{DINGUS2}. 45 Recent results indicate that the spectrum of some GRBs contains a very hard, luminous, long-duration component~\cite{GONZALES}. 46 There have been results suggesting gamma rays beyond the GeV range from the TIBET air shower array 47 in coincidence with BATSE bursts~\cite{AMENOMORI}, rapid follow-up observations by the 48 Whipple Air Cherenkov Telescope~\cite{CONNAUGHTON1}, and coincident and monitoring studies by 49 HEGRA-AIROBICC~\cite{PADILLA}, Whipple~\cite{CONNAUGHTON2} and the Milagro prototype Milagrito~\cite{MILAGRO}. 50 The GRAND array has reported some excess of observed muons during seven BATSE bursts~\cite{GRAND}. 51 In this context, especially the publication from the TASC detector on \eg is important~\cite{GONZALES}, 52 finding a HE spectral component presumably due to the ultra-relativistic acceleration of hadrons and 53 producing a spectral index of $-1$ with no cut-off up to the detector energy limit at 200\,MeV.\\ 36 The only significant detections were performed by \eg, that was able to observe seven GRBs emitting HE photons with energies between 100\,MeV and 18\,GeV~\cite{EGRET, DINGUS1}. The data shows a HE spectral component presumably due to the ultra-relativistic acceleration of hadrons and producing a spectral index of $-1$ with no cut-off up to the TASC detector energy limit at 200\,MeV~\cite{DINGUS2, GONZALES}. Recent results indicate that the spectrum of some GRBs contains a very hard, luminous, long-duration component~\cite{GONZALES}. 37 There have been results suggesting gamma rays beyond the GeV range from the TIBET air shower array in coincidence with BATSE bursts~\cite{AMENOMORI}, rapid follow-up observations by the Whipple Air Cherenkov Telescope~\cite{CONNAUGHTON1}, and coincident and monitoring studies by HEGRA-AIROBICC~\cite{PADILLA}, Whipple~\cite{CONNAUGHTON2} and the Milagro prototype Milagrito~\cite{MILAGRO}. 38 The GRAND array has reported some excess of observed muons during seven BATSE bursts~\cite{GRAND}.\\ 54 39 55 40 To estimate the observability of GRB by \ma, sources of the … … 78 63 If there is a connection between XRFs and GRBs, they should originate at rather low redshifts ($z < 0.6$) 79 64 because otherwise, the XRF energies would not fit into the observed correlation 80 between GRB peak energy and isotropic energy release~\cite{LEVAN}. \\ 81 82 Gamma-ray satellites react in the same way to XRFs and GRBs. 83 In case of a detection the coordinates are distributed 84 to other observatories (see section 2.1). Only from later analysis the difference can be established. 85 86 \par 87 88 We include therefore the observation of XRFs by \ma in this proposal. 65 between GRB peak energy and isotropic energy release~\cite{LEVAN}. 89 66 90 67 \subsection{Observation of SGRs} … … 97 74 98 75 The BAT instrument on the SWIFT satellite triggered on an outburst from SGR1806-20 on January $30^{\mathrm{th}}$, 2005. 99 The fluence was about $10^{-5}$\,erg/cm$^2$ in the range between 15 and 350\,keV. 100 This event was five orders of magnitude smaller than the giant flare from this source on the 101 December 27$^{\mathrm{th}}$, 2004~\cite{GCN3002}. 76 The fluence was about $10^{-5}\mathrm{erg}\cdot\mathrm{cm}^{-2}$ in the range between 15 and 350\,keV. 77 This event was five orders of magnitude smaller than the giant flare from this source on the December 27$^{\mathrm{th}}$, 2004~\cite{GCN3002}. 102 78 MAGIC has enough sensitivity for observing events with fluences bigger than $2.5 \times 10^{-2}\mathrm{erg}\cdot\mathrm{cm}^{-2}\mathrm{s}^{-1}$ at 100\,keV, when a spectral index of $-2.0$ and 100\,s of observation time are assumed. 103 Therefore if an SGR as the giant flare of SGR1806-20 occurs, MAGIC would be able to detect its $\gamma$-ray emission. 79 Therefore if an SGR as the giant flare of SGR1806-20 occurs, MAGIC would be able to detect its $\gamma$-ray emission.\\ 104 80 105 %%% Local Variables: 81 Gamma-ray satellites react in the same way to XRFs, SGRs and GRBs. 82 In case of a detection the coordinates are distributed to other observatories (see section 2.1). Only from later analysis the difference can be established. We include therefore the observation of XRFs and SGRs by \ma in our proposal. 83 84 85 %%% Local Variables: 106 86 %%% mode: latex 107 87 %%% TeX-master: "GRB_proposal_2005" 108 %%% End: 88 %%% End:
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