Changeset 6830 for trunk/MagicSoft
- Timestamp:
- 03/16/05 13:55:41 (20 years ago)
- Location:
- trunk/MagicSoft/GC-Proposal
- Files:
-
- 2 added
- 1 edited
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trunk/MagicSoft/GC-Proposal/GC.tex
r6825 r6830 341 341 %\end{figure} 342 342 343 Preliminary conclusion : ?????????????????? 343 The results of the preliminary analysis can be summarized as follows. After the gamma/hadron separation, the ALPHA distributions of the ON data show excess signals of 121 and 32 events, with significances of 5.2 and 3.7 $\sigma$, for SIZE values above 300 p.e. and 800 p.e., respectively. If the SIZE cut at 300 p.e. corresponds to an energy threshold of 1.9 TeV and if the effective collection area is assumed to be 1.e5 m$^2$ the observed excess is by a factor of 10 higher than that expected on the basis of the HESS flux. 344 345 Studies are going on concerning appropriate OFF data, the false-source plot and better estimates of the energy threshold and the effective collection area. 346 344 347 345 348 … … 348 351 349 352 \subsection{Expected gamma-ray fluxes} 350 The HESS collaboration has observed the GC for 16.5 hours, at zenith angles around 20 degrees, with energy thresholds between 165 and 255 GeV. The total number of excess events amounts to $\sim$300 , and the differential gamma flux is measured as \cite{GC_hess}:353 The HESS collaboration has observed the GC for 16.5 hours, at zenith angles around 20 degrees, with energy thresholds between 165 and 255 GeV. The total number of excess events amounts to $\sim$300. The differential gamma flux as determined in the energy region from 200 GeV to 10 TeV is \cite{GC_hess}: 351 354 352 355 \begin{equation} … … 411 414 \subsection{Verification of the MAGIC analysis at high zenith angles} 412 415 In order to verify the correct performance of the MAGIC analysis at high ZA it is proposed to take Crab data in the interesting ZA range from 58$^{\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. 416 417 ???? Propose suitable OFF regions ??? 413 418 414 419 … … 461 466 %\end{table} 462 467 468 The star field around the GC, including stars up to a magnitude of 14, is depicted in Figure \ref{fig:GC_starfield}. Within a distance of 1$^{\circ}$ from the GC there are no stars brighter than mag = 8.4, and there are 16 stars with $8<$ mag $<9$. At distances between 1$^{\circ}$ and 1.75$^{\circ}$ from the GC the total number of stars with $4<$ mag $<9$ is 26. The brightest ones are Sgr 3 with mag = 4.5, GSC 6836-0644 with mag = 6.4 and GSC 6839-0196 with mag = 7.2. 469 463 470 \subsection{Wobble mode} 464 The star field around the GC, including stars up to a magnitude of 14, is depicted in Figure \ref{fig:GC_starfield}. One can see that the star field is roughly uniform except for the left lower part (RA$\;>\;$RA$_{GC}+4.7$ min), where the field is significantly brighter. The sky directions (WGC1, WGC2) to be tracked in the wobble mode should be chosen such that in the camera the sky field relative to the source position (GC) is similar to the sky field relative to the mirror source position (anti-source position). For this reason the prefered directions for the wobble mode are WGC1 = (RA$_{GC}$, dec$_{GC}$+0.4$^{\circ}$) and WGC2 = (RA$_{GC}$, dec$_{GC}$-0.4$^{\circ}$. During one night, 50\% of the data should be taken at WGC1 and 50\% at WGC2, switching between the 2 directions every 30 minutes. 471 472 As can be seen from Figure \ref{fig:GC_starfield} the star field around the GC is roughly uniform except for the left lower part (RA$\;>\;$RA$_{GC}+4.7$ min), from the GC 1$^{\circ}$ to the left, where the field is significantly brighter. The sky directions (WGC1, WGC2) to be tracked in the wobble mode should be chosen such that in the camera the sky field relative to the source position (GC) is similar to the sky field relative to the mirror source position (anti-source position). For this reason the prefered directions for the wobble mode are WGC1 = (RA$_{GC}$, dec$_{GC}$+0.4$^{\circ}$) and WGC2 = (RA$_{GC}$, dec$_{GC}$-0.4$^{\circ}$. During one night, 50\% of the data should be taken at WGC1 and 50\% at WGC2, switching between the 2 directions every 30 minutes. 473 474 A larger sky area than in Fig.\ref{fig:GC_starfield} is shown in Figs. \ref{fig:GC_starfield_largeW} and \ref{fig:GC_starfield_OFF1}. The circles in the center indicate the region around the GC. The positions of WGC1 and WGC2 are indicated as full circles. 465 475 466 476 \begin{figure}[h!] … … 468 478 \includegraphics[totalheight=16cm]{GCregion14.eps} 469 479 \end{center} 470 \caption[Star field around the GC.]{Star field around the GC. Stars up to a magnitude of 14 are plotted. The 2 big circles correspond to distances of 1$^{\circ}$ and 1.75$^{\circ}$ from the GC, respectively. The x axis is pointing into the direction of decreasing RA, the y axis into the direction of increasing declination. The grid spacing in the declination is 20 arc minutes. 480 \caption[Star field around the GC.]{Star field around the GC. Stars up to a magnitude of 14 are plotted. The 2 big circles correspond to distances of 1$^{\circ}$ and 1.75$^{\circ}$ from the GC, respectively. The x axis is pointing into the direction of decreasing RA, the y axis into the direction of increasing declination. The grid spacing in the declination is 20 arc minutes. The Galactic Plane is given by the dotted line. 471 481 } \label{fig:GC_starfield} 472 482 \end{figure} … … 474 484 \begin{figure}[h!] 475 485 \begin{center} 476 \includegraphics[totalheight=16cm]{GCregion14large .eps}477 \end{center} 478 \caption[Star field around the GC.]{Star field around the GC. Stars up to a magnitude of 14 are plotted. The 2 big circles correspond to distances of 1$^{\circ}$ and 1.75$^{\circ}$ from the GC, respectively. The x axis is pointing into the direction of decreasing RA, the y axis into the direction of increasing declination. The grid spacing in the declination is 1 degree.479 } \label{fig:GC_starfield_large }480 \end{figure} 481 482 \begin{figure}[h!] 483 \begin{center} 484 \includegraphics[totalheight=16cm]{GCregionOFF .eps}485 \end{center} 486 \caption[Star field around the GC.]{Star field around the GC. Stars up to a magnitude of 1 2are plotted. The ON region is indicated by the bigger circle in the center. A possible OFF region is shown by the bigger circle in the left upper part of the figure. The x axis is pointing into the direction of decreasing RA, the y axis into the direction of increasing declination. The grid spacing in the declination is 1 degree.487 } \label{fig:GC_starfield_OFF }486 \includegraphics[totalheight=16cm]{GCregion14largeW.eps} 487 \end{center} 488 \caption[Star field around the GC.]{Star field around the GC. Stars up to a magnitude of 14 are plotted. The 2 big circles correspond to distances of 1$^{\circ}$ and 1.75$^{\circ}$ from the GC, respectively. The wobble positions WGC1 and WGC2 are given by the full circles. The x axis is pointing into the direction of decreasing RA, the y axis into the direction of increasing declination. The grid spacing in the declination is 1 degree. 489 } \label{fig:GC_starfield_largeW} 490 \end{figure} 491 492 \begin{figure}[h!] 493 \begin{center} 494 \includegraphics[totalheight=16cm]{GCregionOFF1.eps} 495 \end{center} 496 \caption[Star field around the GC.]{Star field around the GC. Stars up to a magnitude of 14 are plotted. The ON region is indicated by the bigger circle in the center. A possible OFF region is shown by the bigger circle in the left upper part of the figure. The x axis is pointing into the direction of decreasing RA, the y axis into the direction of increasing declination. The grid spacing in the declination is 1 degree. 497 } \label{fig:GC_starfield_OFF1} 488 498 \end{figure} 489 499 490 500 \subsection{ON/OFF mode} 491 501 492 A larger sky area than in Fig.\ref{fig:GC_starfield} is shown in Figs. \ref{fig:GC_starfield_large} and \ref{fig:GC_starfield_OFF}. The bigger circle in the center indicates the ON region around the GC. An appropriate OFF region, with a sky field similar to that of the ON region, would be the one marked by the bigger circle in the upper left part of Fig.\ref{fig:GC_starfield_OFF} . It is centered at the Galactic Plane, contains the bright star Sgr 3 (at (RA, dec) = $(17^h47^m34^s,\;-27^{\circ}49'51"$) ) in its outer part and has the coordinates GC$_{OFF}$ = (RA, dec) = $(17^h52^m00^s,\;-26^{\circ}39'06")$. The difference in RA between the GC and GC$_{OFF}$ corresponds to about 7 minutes. 502 The bigger circle in the center of Fig. \ref{fig:GC_starfield_OFF1} 503 indicates the ON region around the GC. 504 An appropriate OFF region, with a sky field similar to that of the ON region, would be the one marked by the bigger circle in the upper left part of Fig.\ref{fig:GC_starfield_OFF1} . Like the ON region, the OFF region is centered at the Galactic Plane and contains the bright star Sgr 3 (at (RA, dec) = $(17^h47^m34^s,\;-27^{\circ}49'51"$) ) in its outer part. The center of the OFF region has the coordinates GC$_{OFF}$ = (RA, dec) = $(17^h51^m12^s,\;-26^{\circ}52'00")$. The difference in RA between the GC and GC$_{OFF}$ corresponds is 6 minutes. Thus GC$_{OFF}$ culminates 6 minutes later than the GC. 493 505 494 506 %In order to have the most appropriate OFF data we propose to
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