Changeset 6587 for trunk/MagicSoft


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Timestamp:
02/18/05 11:24:10 (20 years ago)
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garcz
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  • trunk/MagicSoft/GRB-Proposal/Introduction.tex

    r6550 r6587  
    1919\par
    2020
    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
     21Possible causes range from proton-synchrotron emission~\cite{TOTANI} to
     22photon-pion production~\cite{WAXMAN,BOETTCHER} and inverse-Compton scattering
    2423in 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}.
     24A long-term high energy (HE) $\gamma$-emission can come from accelerated protons in the forward-shock, as predicted in~\cite{LI}.
     25This model predicts GeV inverse Compton emission up to one day after the burst.
     26Even considering pure electron-synchrotron radiation, measurable GeV-emission for a significant
     27fraction of GRBs is predicted~\cite{ZHANG2}.
    3728
    3829\par
    3930
     31GeV-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
    4034Several attempts were made in the past to observe GRBs in the GeV range,
    4135each 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.\\
     36The 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}.
     37There 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}.
     38The GRAND array has reported some excess of observed muons during seven BATSE bursts~\cite{GRAND}.\\
    5439
    5540To estimate the observability of GRB by \ma, sources of the
    … …  
    7863If there is a connection between XRFs and GRBs, they should originate at rather low redshifts ($z < 0.6$)
    7964because 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.
     65between GRB peak energy and isotropic energy release~\cite{LEVAN}.
    8966
    9067\subsection{Observation of SGRs}
    … …  
    9774
    9875The 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}.
     76The fluence was about $10^{-5}\mathrm{erg}\cdot\mathrm{cm}^{-2}$ in the range between 15 and 350\,keV.
     77This event was five orders of magnitude smaller than the giant flare from this source on the December 27$^{\mathrm{th}}$, 2004~\cite{GCN3002}.
    10278MAGIC 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.
     79Therefore if an SGR as the giant flare of SGR1806-20 occurs, MAGIC would be able to detect its $\gamma$-ray emission.\\
    10480
    105 %%% Local Variables:
     81Gamma-ray satellites react in the same way to XRFs, SGRs and GRBs.
     82In 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:
    10686%%% mode: latex
    10787%%% TeX-master: "GRB_proposal_2005"
    108 %%% End: 
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