Changeset 6690
- Timestamp:
- 03/01/05 09:48:54 (20 years ago)
- Location:
- trunk/MagicSoft/GC-Proposal
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- 2 edited
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trunk/MagicSoft/GC-Proposal/Changelog
r6673 r6690 1 2 2005/03/01 Sebastian 3 * some minor corrections 4 1 5 2005/02/24 Hendrik 2 6 * all new 7 -
trunk/MagicSoft/GC-Proposal/GC.tex
r6675 r6690 31 31 } 32 32 \author{H. Bartko, A. Biland, S. Commichau, P. Flix, W. Wittek} 33 \date{M onth dd, 2005\\}33 \date{March dd, 2005\\} 34 34 \TDAScode{}%MAGIC 05-xx\\ 04mmdd/HBartko 35 35 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% … … 40 40 %% abstract %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 41 41 \begin{abstract} 42 The Galactic Center (GC) is a very interesting region. Gamma radiation above a few hundred GeV has been detected recently by Whipple, Cangaroo and HESS. The reconstructed spectra from Cangaroo and HESS show significant differences the source and acceleration mechanism have still to be identified. 43 44 Various possibilities for the acceleration of the very high energy gamma rays are discussed in the literature (like...). Although the observed VHE gamma radiation from the GC is most probably not due to SUSY-neutralino particle dark matter annihilation, other models like Kaluza-Klein DM are not ruled out. Moreover assuming an universal DM distribution profile, the GC is expected to yield the largest DM flux due to its relative vicinity. 45 46 47 The GC culminates at about 58 deg ZA in La Palma. It can be observed up to 60 deg ZA with MAGIC during about 153 hours per year between April and late August. The expected integral flux above 700 GeV derived from the HESS data is $(3.2 \pm 1.0)\cdot 10^{-12}\mathrm{cm}^{-2}\mathrm{s}^{-1}$ . Comparing this to the expected MAGIC sensitivity from MC simulations, this could result in a 5 $\sigma$ detection in about $1.8\pm0.5$ hours. 42 The Galactic Center (GC) is a very interesting region. Gamma radiation above a few hundred GeV has been detected recently by Whipple, Cangaroo and HESS. The reconstructed spectra from Cangaroo and HESS show significant differences. Source and acceleration mechanism have still to be identified. 43 44 Various possibilities for the acceleration of the very high energy gamma rays 45 are discussed in the literature (like...). Although the observed VHE gamma 46 radiation from the GC is most probably not due to SUSY-neutralino particle 47 dark matter (DM) annihilation, other models like Kaluza-Klein dark matter are not ruled out. Moreover, assuming a universal DM distribution profile, the GC is expected to yield the largest DM flux due to its relative vicinity. 48 49 50 The GC culminates at about 58 deg ZA in La Palma. It can be observed with 51 MAGIC at up to 60 deg ZA for about 150 hours per year between April and late August. The expected integral flux above 700 GeV derived from the HESS data is $(3.2 \pm 1.0)\cdot 10^{-12}\mathrm{cm}^{-2}\mathrm{s}^{-1}$. Comparing this to the expected MAGIC sensitivity from MC simulations, this could result in a 5 $\sigma$ detection in about $1.8\pm0.5$ hours. 48 52 49 53 The observations have to be conducted as early as possible to participate in the exciting physics of the Galactic Center. The main motivations are: … … 56 60 57 61 58 To get a comparable data set to the other experiments and to be able to reconstruct the spectrum an observation of 20 hours plus 20 hours of dedicated OFF data would be needed and hereby applied for. Moreover due to the large threshold moon observations are envisaged and 60 hours are applied for.62 To get a comparable data set to the other experiments and to be able to reconstruct the spectrum, an observation of 20 hours plus 20 hours of dedicated OFF data would be needed and hereby applied for. Moreover due to the large threshold moon observations are envisaged and 60 hours are applied for. 59 63 \end{abstract} 60 64 … … 81 85 \begin{tabular}{lc} 82 86 \hline 83 (RA, dec), epoch J2000.0 & $(17^h45^m12^s,-29.01 deg)$87 (RA, dec), epoch J2000.0 & $(17^h45^m12^s,-29.01$ deg) 84 88 \\ heliocentric distance & $8\pm0.5$ kpc (1 deg = 24 pc) 85 89 \\ mass of the black hole & $2\pm0.5 \cdot 10^6 M_{\odot}$ … … 100 104 101 105 102 In fact, EGRET has detected a strong source in thedirection of the GC, 3 EG J1745-2852 \cite{GC_egret}, which has a broken power law spectrum extending up to at least 10 GeV, with the index 1.3 below the bread at a few GeV. If in the GC, the gamma ray luminosity of this source is very large $~2 \cdot 10^{37} \mathrm{erg}/\mathrm{s}$, which is equivalent to about 10 Crab pulsars. Up to now, the GC has been observed at energies above 200 GeV by Veritas, Cangaroo and HESS, \cite{GC_whipple,GC_cangaroo,GC_hess}. Figure \ref{fig:GC_gamma_flux} shows the reconstructed spectra by the other IACTs while figure \ref{fig:GC_source_location} shows the different reconstructed positions of the GC source.106 In fact, EGRET has detected a strong source in direction of the GC, 3 EG J1745-2852 \cite{GC_egret}, which has a broken power law spectrum extending up to at least 10 GeV, with the index 1.3 below the bread at a few GeV. If in the GC, the gamma ray luminosity of this source is very large $~2 \cdot 10^{37} \mathrm{erg}/\mathrm{s}$, which is equivalent to about 10 Crab pulsars. Up to now, the GC has been observed at energies above 200 GeV by Veritas, Cangaroo and HESS, \cite{GC_whipple,GC_cangaroo,GC_hess}. Figure \ref{fig:GC_gamma_flux} shows the reconstructed spectra by the other IACTs while figure \ref{fig:GC_source_location} shows the different reconstructed positions of the GC source. 103 107 104 108 \begin{figure}[h!] … … 117 121 \end{figure} 118 122 119 The different reconstructed spectra in VHE gammas could indicate inter-calibration problems between the IACTs, a source variability of the order of one year orcould be due to the different regions in which the signal is integrated.123 The different reconstructed spectra in VHE gammas could indicate inter-calibration problems between the IACTs, a source variability of the order of one year could be due to the different regions in which the signal is integrated. 120 124 121 125 … … 127 131 128 132 \begin{table}[h]{ 129 \scriptsize{ %130 \centering 133 \scriptsize{ 134 \centering{ 131 135 \begin{tabular}{llll} 132 136 \hline 133 Investigator & Institution& email & Assigned task137 Investigator & Institution& E-mail & Assigned task 134 138 \\ 135 139 \\ Hendrik Bartko & MPI Munich & hbartko@mppmu.mpg.de & data analysis, spectra 136 140 \\ Adrian Biland & ETH Zurich & biland@particle.phys.ethz.ch & OFF pointing, Moon observations 137 \\ Sebastian Commichau & ETH Zurich & commichau@particle.phys.ethz.ch & data analysis, MC generation 141 \\ Sebastian Commichau & ETH Zurich & commichau@particle.phys.ethz.ch & 142 data analysis, MC generation, spectra 138 143 \\ Pepe Flix & IFAE Barcelona& jflix@ifae.es & data analysis, disp 139 144 \\ Wolfgang Wittek & MPI Munich & wittek@mppmu.mpg.de & padding … … 142 147 \end{tabular} 143 148 } 144 \caption{The investigators and assigned tasks.}\label{table:GC_investigators}} 149 \caption{The investigators and assigned tasks.}\label{table:GC_investigators}}} 145 150 \end{table} 146 147 148 149 151 150 152 \section{Scientific Case} … … 209 211 210 212 \begin{equation} 211 \frac{\mathrm{d}N_{\gamma}}{\mathrm{d}A\mathrm{d}t\mathrm{d}E} = (2.50 \pm 0.21 \pm 0.6) \cdot 10^{-12} \frac{1}{\mathrm{cm}^2 s\mathrm{TeV}} \left(\frac{E}{\mathrm{TeV}}\right)^{-2.21\pm 0.09 \pm 0.15}213 \frac{\mathrm{d}N_{\gamma}}{\mathrm{d}A\mathrm{d}t\mathrm{d}E} = (2.50 \pm 0.21 \pm 0.6) \cdot 10^{-12} \frac{1}{\mathrm{cm}^2\mathrm{sTeV}} \left(\frac{E}{\mathrm{TeV}}\right)^{-2.21\pm 0.09 \pm 0.15} 212 214 \end{equation} 213 215 … … 215 217 216 218 \begin{equation} 217 \frac{\mathrm{d}N_{\gamma}}{\mathrm{d}A\mathrm{d}t\mathrm{d}E} = (3.4 \pm 3.8) \cdot 10^{-12} \frac{1}{\mathrm{cm}^2s\mathrm{TeV}} \left(\frac{E}{\mathrm{TeV}}\right)^{-4.4\pm 1.1} 218 \end{equation} 219 219 \frac{\mathrm{d}N_{\gamma}}{\mathrm{d}A\mathrm{d}t\mathrm{d}E} = (3.4 \pm 3.8) \cdot 10^{-12} \frac{1}{\mathrm{cm}^2\mathrm{sTeV}} \left(\frac{E}{\mathrm{TeV}}\right)^{-4.4\pm 1.1} 220 \end{equation} 220 221 221 222 … … 223 224 224 225 \begin{equation} 225 \frac{\mathrm{d}N_{\gamma}(E>700 \mathrm{GeV})}{\mathrm{d}A\mathrm{d}t}=(3.2 \pm 1.0)\cdot 10^{-12}\frac{1}{\mathrm{cm}^2 s}226 \frac{\mathrm{d}N_{\gamma}(E>700 \mathrm{GeV})}{\mathrm{d}A\mathrm{d}t}=(3.2 \pm 1.0)\cdot 10^{-12}\frac{1}{\mathrm{cm}^2\mathrm{s}} 226 227 \end{equation} 227 228 … … 230 231 231 232 \begin{equation} 232 \frac{\mathrm{d}N_{\gamma}(E>700 \mathrm{GeV})}{\mathrm{d}A\mathrm{d}t}=(3 \pm 5)\cdot 10^{-12}\frac{1}{\mathrm{cm}^2 s} \ .233 \frac{\mathrm{d}N_{\gamma}(E>700 \mathrm{GeV})}{\mathrm{d}A\mathrm{d}t}=(3 \pm 5)\cdot 10^{-12}\frac{1}{\mathrm{cm}^2\mathrm{s}} \ . 233 234 \end{equation} 234 235 … … 239 240 240 241 \begin{equation} 241 \frac{\mathrm{d}N_{\gamma}(E>700 \mathrm{GeV})}{\mathrm{d}A\mathrm{d}t}\vline_{\mathrm{min}} \approx 6\cdot 10^{-13}\frac{1}{\mathrm{cm}^2s} \ . 242 \end{equation} 243 244 Assuming this sensitivity MAGIC shall be able to get an excess at the 5 sigma significance level in $1.8 \pm 0.5$ h observation time for both the Cangaroo and HESS spectrum. The observed Cangaroo and HESS spectra differ substantially in the spectral index. While the Cangaroo spectrum only extends to about 2 TeV, the published HESS spectrum goes up to about 9 TeV. 242 \frac{\mathrm{d}N_{\gamma}(E>700 \mathrm{GeV})}{\mathrm{d}A\mathrm{d}t}\vline_{\mathrm{min}} \approx 6\cdot 10^{-13}\frac{1}{\mathrm{cm}^2\mathrm{s}} \ . 243 \end{equation} 244 245 Assuming this sensitivity MAGIC shall be able to get an excess at the 5 246 $\sigma$ significance level in $1.8 \pm 0.5$ h observation time for both the 247 Cangaroo and HESS spectrum. The observed Cangaroo and HESS spectra differ 248 substantially in the spectral index. While the Cangaroo spectrum only extends 249 to about 2 TeV, the recently published HESS spectrum goes up to about 9 TeV. 245 250 246 251 MAGIC will be able to solve the obvious discrepancy between the observed fluxes. Due to the observation under high zenith angle of about 60 deg MAGIC will be able to extend the source spectrum to higher energies. … … 255 260 256 261 257 The galactic center culminates at about 58 deg ZA in La Palma. It is visible up to 60 deg ZA between April and late August for in total about 150 hours. The galactic center has a quite large LONS background. This together with the large ZA requires to take dedicated OFF data. Scince the LONS level is in any case very large moon observations can be considered in addition to the normal observations. 262 The galactic center culminates at about 58 deg ZA in La Palma. It is visible 263 at up to 60 deg ZA between April and late August for in total about 150 hours. The galactic center has a quite large LONS background. This together with the large ZA requires to take dedicated OFF data. Since the LONS level is in any case very large moon observations can be considered in addition to the normal observations. 258 264 259 265 … … 269 275 Based on the above estimations a 5 $\sigma$ excess is expected to be observed in about 2 hours assuming the HESS flux. To aquire a comparable data set to the other experiments at least 20 hours of good ON data and 20 hours of good dedicated OFF data are needed. 270 276 271 To get the lowest possible threshold all data shall be taken under the smallest possible zenith angles between culmination at about 58 deg and 60 deg. This limits the data taking interval to about 1 hour per night between April and August. In order to have the most appropriate OFF data we propose to take OFF data each night directly before or after the ON observations under the same condition, i.e. ZA and azimuth. 272 273 To extend the available observation time we propose to take moon ON and OFF data in addition. Nevertheless the proposed maximum ZA of 60 deg should not be exceeded during moon observations. 274 275 In order to take part in exploring the exciting physics of the galactic center we propose to start taking data as soon as possible beginning in April. This way first results may be presented in the summer conferences 2005. 277 To get the lowest possible threshold all data shall be taken under the 278 smallest possible zenith angles between culmination at about 58 deg and 60 279 deg. This limits the data taking interval to about 1 hour per night between 280 April and August. In order to have the most appropriate OFF data we propose to 281 take OFF data each night directly before or after the ON observations under 282 the same condition, i.e. ZA and azimuth. At such high zenith angles the effect 283 of the earth's magnetic field can be non-negligible. This depends of course on 284 ZA and azimuth under which the data is taken. 285 286 To extend the available observation time we propose to take moon ON and OFF data in addition. Nevertheless, the proposed maximum ZA of 60 deg should not be exceeded during moon observations. 287 288 In order to take part in exploring the exciting physics of the galactic center 289 we propose to start taking data as soon as possible beginning in April. In this way first results may be presented in the summer conferences 2005. 276 290 277 291 … … 282 296 Conventional acceleration mechanisms are due to ... The galactic center is expected to be the brightest source of VHE gammas from particle dark matter annihilation. Although the observed gamma radiation is most probably not due to dark matter annihilation, it is interesting to investigate and characterize the observed gamma radiation as it is not excluded that a part of the flux is due to dark matter annihilation. 283 297 284 The MAGIC data could help to determine the nature of the source and to solve the flux discrepancies between the measurements by theother experiments. Due to the large Zenith angle MAGIC will have a large energy threshold but also a large collection area and good statistics at the highest energies. The observation results can also be used to inter-calibrate the different IACTs.298 The MAGIC data could help to determine the nature of the source and to solve the flux discrepancies between the measurements by other experiments. Due to the large Zenith angle MAGIC will have a large energy threshold but also a large collection area and good statistics at the highest energies. The observation results can also be used to inter-calibrate the different IACTs. 285 299 286 300
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