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trunk/MagicSoft/GC-Proposal/GC.tex
r6865 r6866 277 277 where $\langle \sigma v \rangle$ is the thermally averaged annihilation cross section, $m_{\chi}$ the mass and $\rho_{\chi}$ the spatial density distribution of the hypothetical dark matter particles. $N_{\gamma}(E_{\gamma}>E_{\mathrm{th}})$ is the gamma yield above the threshold energy per annihilation. The predicted flux depends on the dark matter particle properties 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. 278 278 279 Supersymmetric extensions of the standard model predict the existance of a good dark matter candidate, the neutralino $\chi$. In most models its mass is below a few TeV. Thus also the expected spectral cut-off lies below a few TeV. As the observed spectrum by the HESS experiment extends above 10 TeV it is very unlikely to be only due to neutralino annihilation.279 %Supersymmetric extensions of the standard model predict the existance of a good dark matter candidate, the neutralino $\chi$. In most models its mass is below a few TeV. Thus also the expected spectral cut-off lies below a few TeV. As the observed spectrum by the HESS experiment extends above 10 TeV it is very unlikely to be only due to neutralino annihilation. 280 280 281 281 … … 426 426 that in the ZA range from 60 to 70 degrees the energy threshold rises from 700 GeV to 1900 GeV. Correspondingly, the time necessary for observing a 5$\sigma$ excess (assuming an integrated gamma flux as measured by HESS) increases from 1.8 to 8.9 hours. This strongly suggests the MAGIC data to be taken at the smallest ZA possible. Only then the MAGIC observations will contribute to an understanding of the discrepancies between the HESS and Cangaroo results. Due to the observation under high zenith angles ($\sim$60 deg) MAGIC will be able to extend the measurements of the energy spectrum to higher energies ($\sim$20 TeV). 427 427 428 The HESS experiment has a PSF (in stereo mode) of about 0.6 deg while MAGIC has about 0.1 deg PSF. 429 430 431 ???? We still have no good estimate of the expected number of excess event for the different conditions. ??? \\432 433 ???? How long do we have to observe to get a good spectrum above 7 TeV ??? \\428 The HESS experiment has a PSF (in stereo mode) of about 0.6 deg while MAGIC has about 0.1 deg PSF. Thus MAGIC can also contribute to the determination of the exacct source position and a possible source extension. 429 430 431 % ???? We still have no good estimate of the expected number of excess event for the different conditions. ??? \\ 432 433 % ???? How long do we have to observe to get a good spectrum above 7 TeV ??? \\ 434 434 435 435 \subsection{Verification of the MAGIC analysis at high zenith angles} 436 In order to verify the correct performance of the MAGIC analysis at high ZA it is proposed to take Crab data in the interesting ZA range from 58$^{\circ}$ to 70$^{\circ}$, to reconstruct the gamma energy spectrum and to compare it with existing measurements. Like for the GC, either dedicated OFF data should be taken or observations should be made in the wobble mode.437 438 ???? Propose suitable OFF regions ???436 In order to verify the correct performance of the MAGIC analysis at high ZA it is proposed to take Crab data in the interesting ZA range from 58$^{\circ}$ to 70$^{\circ}$, to reconstruct the gamma energy spectrum and to compare it with existing measurements. Like for the GC, the observations should be made in the wobble mode or dedicated OFF data must be taken. 437 438 %???? Propose suitable OFF regions ??? 439 439 440 440 … … 442 442 443 443 444 The GC culminates at about 58 deg ZA in La Palma. Below 60 deg ZA, it is visible between April and late August for about moon-less 150hours. Moreover there are more than 100 hours in the same ZA range with moon light.444 The GC culminates at about 58 deg ZA in La Palma. Below 60 deg ZA, it is visible between April and late August for about 150 moon-less hours. Moreover there are more than 100 hours in the same ZA range with moon light. 445 445 446 446 The GC region has a quite high and non-uniform level of background light from the night sky. This together with the large ZA requires observations in the wobble mode (see Section \ref{section:skydirections}) or to take dedicated OFF data.
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