Changeset 6779


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03/08/05 08:28:25 (20 years ago)
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wittek
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  • trunk/MagicSoft/GC-Proposal/GC.tex

    r6778 r6779  
    107107%<<<<<<< GC.tex
    108108
    109 %The Galactic Center (GC) region contains many unusual objects which may be responsible for the high energy processes generation gamma rays \cite{Aharonian2005,Atoyan2004,Horns2004}. The GC is rich in massive stellar clusters with up to 100 OB stars \cite{GC_environment}, immersed in a dense gas within the volume of 300 pc and the mass of $2.7 \cdot 10^7 M_{\odot}$, young supernova remnants e.g. G0.570-0.018 or Sgr A East, and nonthermal radio arcs. The dynamical center of the Milky Way is associated with the compact radio source Sgr A$^*$, which is believed to be a massive black hole \cite{GC_black_hole,Melia2001}. An overview of the sources in the GC region is given in figure \ref{fig:GC_sources}. Some data about the Galactic Center are summarized in table \ref{table:GC_properties}.
     109%The Galactic Center (GC) region contains many unusual objects which may be responsible for the high energy processes generation gamma rays \cite{Aharonian2005,Atoyan2004,Horns2004}. The GC is rich in massive stellar clusters with up to 100 OB stars \cite{GC_environment}, immersed in a dense gas within the volume of 300 pc and the mass of $2.7 \cdot 10^7 M_{\odot}$, young supernova remnants e.g. G0.570-0.018 or Sgr A East, and nonthermal radio arcs. The dynamical center of the Milky Way is associated with the compact radio source Sgr A$^*$, which is believed to be a massive black hole \cite{GC_black_hole,Melia2001}. An overview of the sources in the GC region is given in Figure \ref{fig:GC_sources}. Some data about the Galactic Center are summarized in Table \ref{table:GC_properties}.
    110110%=======
    111111The Galactic Center (GC) region contains many unusual objects which may be
     
    114114clusters with up to 100 OB stars \cite{GC_environment}, immersed in a dense
    115115gas within a radius of 300 pc and the mass of $2.7 \cdot 10^7 M_{\odot}$,
    116 young supernova remnants e.g. G0.570-0.018 or Sgr A East, and nonthermal radio arcs. The dynamical center of the Milky Way is associated with the compact radio source Sgr A$^*$, which is believed to be a massive black hole \cite{GC_black_hole,Melia2001}. An overview of the sources in the GC region is given in figure \ref{fig:GC_sources}. Some data about the Galactic Center are summarized in table \ref{table:GC_properties}.
     116young supernova remnants e.g. G0.570-0.018 or Sgr A East, and nonthermal radio arcs. The dynamical center of the Milky Way is associated with the compact radio source Sgr A$^*$, which is believed to be a massive black hole \cite{GC_black_hole,Melia2001}. An overview of the sources in the GC region is given in Figure \ref{fig:GC_sources}. Some data about the Galactic Center are summarized in Table \ref{table:GC_properties}.
    117117%>>>>>>> 1.15
    118118
     
    152152energies above 200 GeV by Veritas, Cangaroo and HESS, \cite{GC_whipple,
    153153GC_cangaroo,GC_hess}. Figure \ref{fig:GC_gamma_flux} shows the reconstructed
    154 spectra by the other IACTs while figure \ref{fig:GC_source_location} shows the
     154spectra by the other IACTs while Figure \ref{fig:GC_source_location} shows the
    155155different reconstructed positions of the GC source. Recently a second TeV
    156156gamma source only about 1 degree away from the Galactic Center has been
     
    179179\section{Investigators and Affiliations}
    180180
    181 The investigators of the proposed observations of the Galactic Center are stated in table \ref{table:GC_investigators} together with their assigned analysis tasks. All other interested members of the MAGIC collaboration are invited to join these efforts.
     181The investigators of the proposed observations of the Galactic Center are stated in Table \ref{table:GC_investigators} together with their assigned analysis tasks. All other interested members of the MAGIC collaboration are invited to join these efforts.
    182182
    183183
     
    218218
    219219
    220 % in the non-thermal radio filaments by high-energy leptons which scatter background infrared photons from the nearby ionized clouds \cite{Pohl1997,Aharonian2005}, or by hadrons colliding with dense matter. These high energy hadrons can be accelerated by the massive black hole \cite{GC_black_hole}, associated with the Sgr A$^*$, supernovae or an energetic pulsar. Alternative mechanisms invoke the hypothetical annihilation of super-symmetric dark matter particles (for a review see \cite{jung96}) or curvature radiation of protons in the vicinity of the central super-massive black hole \cite{GC_black_hole,Melia2001}.
    221 
    222 
    223 In order to shed new light on the high energy phenomena in the GC region, and constrain the emission mechanisms and sources, new observations with high sensitivity, good spectra reconstruction and angular resolution are necessary. For the interpretation of the observed gamma flux the following observables are very important:
     220% in the non-thermal radio filaments by high-energy leptons which scatter background infrared photons from the nearby ionized clouds \cite{Pohl1997,Aharonian2005}, or by hadrons colliding with dense matter. These high energy hadrons can be accelerated by the massive black hole \cite{GC_black_hole}, associated with the Sgr A$^*$, by supernovae or by energetic pulsars. Alternative mechanisms invoke the hypothetical annihilation of super-symmetric dark matter particles (for a review see \cite{jung96}) or curvature radiation of protons in the vicinity of the central super-massive black hole \cite{GC_black_hole,Melia2001}.
     221
     222
     223In order to shed new light on the high energy phenomena in the GC region, and to constrain the emission mechanisms and sources, new observations with high sensitivity, good energy and angular resolution are necessary. For the interpretation of the observed gamma flux the following observables are important:
    224224
    225225\begin{itemize}
    226226\item{source location, source extension}
    227 \item{time variability}
     227\item{time variability of the gamma flux}
    228228\item{energy spectrum.}
    229229\end{itemize}
     
    271271
    272272
    273 where $\langle \sigma v \rangle$ is the thermally averaged cross section, $m_{\chi}$ the mass and $\rho_{\chi}$ the spatial density distribution of the hypothetical dark matter particles. $N_{\gamma}(E_{\gamma}>E_{\mathrm{thresh}})$ is the gamma yield above the threshold energy per annihilation. The flux prediction depends on the choose of SUSY parameters and the spatial distribution of the dark matter. The spectra of the produced gamma radiation has a very characteristic feature a sharp cut-off at the mass of the dark matter particle. Also the flux should be absolutely stable in time.
    274 
    275 Numerical simulations of cold dark matter \cite{NFW1997,Stoehr2002,Hayashi2004,Moore1998} predict universal DM halo profiles with density enhancement in the center of the dark halos. In the very center the dark matter density can even more enhanced through an adiabatic compression due to the baryons \cite{Prada2004} present. All dark matter distributions that predict observable fluxes are cusped yielding an approximately point-like source.
    276 
    277 Using fits of these dark matter profiles to the rotation data of the milky way predictions for the density distribution of the dark matter can be made \cite{Fornego2004,Evans2004}. Assuming parameters for the SUSY models determine the neutralino mass, the thermally averaged annihilation cross section and the gamma yield. Combining both models about the dark matter distribution and SUSY predictions for the gamma flux from SUSY particle dark matter annihilation are derived.
    278 
    279 Figure \ref{fig:exclusion_lmits} shows exclusion limits taking the sensitivity of MAGIC from MC simulations into account for different sources and predictions from typical allowed SUSY models in the plane $N_{\gamma}(E_{\gamma}>E_{\mathrm{thresh}})\langle \sigma v \rangle$ vs. $m_{\chi}$. Due to its relative vicinity the Galactic Center yield the largest expected flux from particle dark matter annihilation. Nevertheless this flux is more than one order of magnitude below the current MAGIC sensitivity. Also the observed flux from the HESS experiment way above the theoretical expectation.
     273where $\langle \sigma v \rangle$ is the thermally averaged annihilation cross section, $m_{\chi}$ the mass and $\rho_{\chi}$ the spatial density distribution of the hypothetical dark matter particles. $N_{\gamma}(E_{\gamma}>E_{\mathrm{thresh}})$ is the gamma yield above the threshold energy per annihilation. The predicted flux depends on the SUSY parameters and on the spatial distribution of the dark matter. The energy spectrum of the produced gamma radiation has a very characteristic feature : a sharp cut-off at the mass of the dark matter particle. Also the flux should be absolutely stable in time.
     274
     275Numerical simulations of cold dark matter \cite{NFW1997,Stoehr2002,Hayashi2004,Moore1998} predict universal DM halo profiles with a density enhancement in the center of the dark halos. In the very center the dark matter density can be even more enhanced through an adiabatic compression due to the baryons \cite{Prada2004} present. All dark matter distributions that predict observable fluxes are cusped, yielding an approximately point-like source.
     276
     277Using fits of these dark matter profiles to the rotation data of the milky way predictions for the density profile $\rho_{\chi}$ of the dark matter can be made \cite{Fornego2004,Evans2004}. On the other hand, for a given choice of SUSY parameters $m_{\chi},\;\langle \sigma v \rangle$ and $N_{\gamma}$ are determined.
     278%Assuming parameters for the SUSY models determine the neutralino mass, the thermally averaged annihilation cross section and the gamma yield. Combining both models about the dark matter distribution and SUSY
     279Combining the SUSY predictions with the predictions for the DM density profile
     280predictions for the gamma flux from SUSY particle dark matter annihilation are derived.
     281
     282Figure \ref{fig:exclusion_lmits} shows exclusion limits for MAGIC (straight lines) for the four most promising sources
     283%taking the sensitivity of MAGIC from MC simulations into account for different sources and predictions from typical allowed SUSY models
     284in the plane $N_{\gamma}(E_{\gamma}>E_{\mathrm{thresh}})\langle \sigma v \rangle$ vs. $m_{\chi}$. Due to its proximity the Galactic Center yields the largest expected flux from particle dark matter annihilation. Nevertheless this flux is more than one order of magnitude below the current MAGIC sensitivity. Also the observed flux from the HESS experiment way above the theoretical expectation.
    280285
    281286
     
    284289\includegraphics[totalheight=6cm]{plot_DM_exclusion.eps}%{Dark_exclusion_limits.eps}
    285290\end{center}
    286 \caption[DM exclusion limits.]{Exclusion limits for different possible sources of dark matter annihilation radiation. The galactic center is expected to give the largest flux from all sources. The observed flux by the HESS experiment is within the reach of MAGIC for energies above about 700 GeV. Nevertheless it is more than one order of magnitude above the typical model predictions.  -- figure to be updated --} \label{fig:exclusion_lmits}
     291\caption[DM exclusion limits.]{Exclusion limits for the four most promising sources of dark matter annihilation radiation. The galactic center is expected to give the largest flux from all sources. For energies above 700 GeV, the flux from the GC as observed by the HESS experiment is within the reach of MAGIC. The solid points represent flux predictions from some typical SUSY models.  -- Figure to be updated --} \label{fig:exclusion_lmits}
    287292\end{figure}
    288293
     
    299304collaboration meeting in Berlin, 21-25th February 2005.\\
    300305Up to now there is only 2.9 hours of ON data available at a very large zenith
    301 angle range. Some details of the data set are shown in table \ref{table:GC_dataset}.\\
     306angle range. Some details of the data set are shown in Table \ref{table:GC_dataset}.\\
    302307
    303308\begin{table}[!ht]{
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