Changeset 6160 for trunk/MagicSoft


Ignore:
Timestamp:
01/31/05 20:07:14 (20 years ago)
Author:
garcz
Message:
*** empty log message ***
Location:
trunk/MagicSoft/GRB-Proposal
Files:
3 edited

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  • trunk/MagicSoft/GRB-Proposal/GRB_proposal_2005.tex

    r6147 r6160  
    163163\bibitem{CONTROL} MAGIC-TDAS 00-07, Cortina J, 2004.
    164164
     165%References used in Strategies
     166
     167\bibitem{KNEISKE} Kneiske T.M., Bretz T., Mannheim K., Hartmann D.H., A\&A 413, 807, 2004.
     168
     169%Not used references
    165170
    166171\bibitem{PAZCYNSKI} Pazcy\'{n}ski B., Astrophys. J. 308 L43 (1986)
     
    171176\bibitem{MESZAROS94} Meszaros P., Rees M., MNRAS 289 L41 (1994)
    172177
    173 \bibitem{KNEISKE} Kneiske T.M., Bretz T., Mannheim K., Hartmann D.H., A\&A 413, 807, 2004.
     178
    174179
    175180\end{thebibliography}
  • trunk/MagicSoft/GRB-Proposal/Monitor.tex

    r6158 r6160  
    148148\subsection{Comparison between the satellite orbits}
    149149
    150 Figure 1 show the difference between the orbits of the \sw, \he and \ig satellite.
     150Figure~\ref{fig:orbit} show the difference between the orbits of the \sw, \he and \ig satellite.
    151151The \sw and \he satellites are situated in a circular orbit with 20.6$^\circ$ respectivly 2$^\circ$ inclination. The revolution period of the \sw and \he satellite add up to 100min. The \ig satellite is situated in an highly eccentric orbit with a revolution period around the Earth of three sidereal days.
    152152
     
    159159\includegraphics[width=0.7\linewidth]{GCNsatellites.eps}
    160160\caption{Orbits of the \sw, \he and \ig satellites}
    161 \label{fig:grh}
     161\label{fig:orbit}
    162162\end{figure}
    163163
  • trunk/MagicSoft/GRB-Proposal/Strategies.tex

    r6148 r6160  
    11\section{Proposed Observation Strategies}
    22
    3 First, we make an estimate of how many observations we will perform.\\
     3A rough estimate of the needed observation time for GRBs derives
     4from the claimed GRB observation frequency of about 150-200 GRBs/year by the \sw
     5collaboration~\cite{SWIFT} and the results of the studies on the \ma duty-cycle
     6made by Nicola Galante~\cite{NICOLA}.
     7Taking into account the calculated duty-cycle of about 10\% and a time intervall of 5 hours
     8from the onset of the GRB, we should be able to point about 1--2 GRB/month.
    49
    5 A rough estimate of the needed observation time for GRBs derives
    6 from the claimed GRB observation frequency  of about 150-200 GRBs/year by the SWIFT
    7 collaboration~\cite{SWIFT} and the results of the studies on the MAGIC duty-cycle
    8 made by Nicola Galante~\cite{NICOLA}.
    9 Considering a MAGIC duty-cycle of about 10\% and a tolerance of 5 hours
    10 to point the GRB, we should be able to point about 1-2 GRB/month.
     10\par
    1111
     12The duty-cycle studies are based on real weather data from the year 2002 taking the following criteria:
    1213
    13 Such duty-cycle studies, made before MAGIC started its observations,
    14 are reliable as long as the considered weather constraints
    15 (~maximum wind speed of 10m/s, maximum humidity of 80\% and
    16 darkness at astronomical horizon~) remain similar to the real ones in 2005.
     14\begin{itemize}
     15\item maximum wind speeds of 10m/s
     16\item maximum humidity of 80\%
     17\item darkness at astronomical horizon
     18\end{itemize}
     19
    1720In these duty-cycle studies also full-moon nights were considered (requiring
    18 a minimum angular distance of the GRB from the moon of 30$^\circ$~),
    19 while we propose here to skip the 3-4 full moon nights per month which are not
    20 yet under observational control.
     21a minimum angular distance between the GRB and the moon of 30$^\circ$).
    2122
    22 This reduction of the real duty-cycle w.r.t. the studies~\cite{NICOLA}
    23 gets compensated by the tolerance of 5 hours for considering the alert observable
    24 (5 hours more before the beginning of the night
    25 are equivalent to an increase of the duty-cycle of about 6 days per month).
    26 Observation interruptions due to technical shifts are not considered here. \\
     23\par
    2724
    28 To conclude, we ask here for about 1-2 nights per month for GRB observations, half-moon nights
    29 included.
    30 Moreover, as the chances go linear with the time that the telescope is able to follow
    31 alerts, we ask do an effort as much as possible to maintain the telescope in alarm position
    32 EVERY time that a GRB follow-up can be considered possible.
     25The duty-cycle in~\cite{NICOLA} will be increased by taking into account that \ma should also observe the afterglow emission of an burst that occured up to 5 hours before the start of the shift. Different GRB models predict delayed prompt GeV emission as well as acceleration of photons during the afterglows up to the threshold energy of \ma (for more details see chapter 5).
    3326
     27The afterglow observation is equivalent to an increase of the duty-cycle of about 6 days per month.\\
    3428
    35 
    36 \subsection{What to do with the AMC ? }
    37 
    38 \ldots {\bf MARKUS G. } \ldots
    3929
    4030\subsection{GRB observations in case of moon shine}
     
    4636a fast moon-flash shouldn't damage the PMTs, but the behaviour
    4737of the camera and the Camera Control {\it La Guagua} must
    48 be tested. On the other hand,, if such test conclude that it is not safe
     38be tested. On the other hand, if such test conclude that it is not safe
    4939to get even a short flash from the moon, the possibility
    50 to implement a new feature into the Steering System must be considered 
     40to implement a new feature into the Steering System must be considered
    5141which follow a path around the moon while slewing.
     42
    5243\par
    53 There was a shift observing the Crab-Nebula with half-moon at La Palma in December 2004.
    54 The experience was that the nominal High-Voltages could be maintained and gave no
    55 currents higher than 2\,$\mu$A. This means that moon-periods can be used for GRB-observations
    56 without fundamental modifications except for full-moon periods. We want to stress that
    57 these periods increase the chances to catch GRBs by 80\%, even if full-moon observations are excluded~\cite{NICOLA}.
    58 It is therefore mandatory that the shifters keep the camera in fully operational conditions with high-voltages
    59 switched on from the beginning of a half-moon night until the end. This includes periods where no other half-moon
    60 observations are scheduled.
     44
     45There was a shift observing the Crab-Nebula with half-moon at La Palma in December 2004.
     46The experience was that the nominal HV could be maintained and gave no
     47currents higher than 2\,$\mu$A. This means that moon-periods can be used for GRB-observations
     48without fundamental modifications except for full-moon periods. We want to stress that
     49these periods increase the chances to catch GRBs by 80\%.
     50It is therefore mandatory that the shifters keep the camera in fully operational conditions with high-voltages switched on from the beginning of a half-moon night until the end. This includes periods where no other half-moon observations are scheduled. If no other data can be taken during the this periond, the telescope shuld be pointed in the north direction, close to the zenith. This increase the probability to overlap with the FOV of the satellites.
     51
    6152\par
    62 Because the background is higher with moon-light, we want to decrease then the maximun zenith angle from
    63 $\theta^{max} = 70^\circ$ to $\theta^{max} = 65^\circ$.
     53
     54Because of higher background with moon-light, we suggest to decrease the maximun zenith angle from
     55$\theta_{max} = 70^\circ$ to $\theta_{max} = 65^\circ$.
    6456
    6557\subsection{Calibration}
    6658
    67 For ordinary source observation, the calibration is currently performed in the following way:
     59For ordinary source observation, the calibration is currently performed in the following way:
     60
    6861\begin{itemize}
    69 \item At the beginning of the source observation, a dedicated pedestal run followed by a calibration run is
    70 taken.
     62\item At the beginning of the source observation, a dedicated pedestal run followed by a calibration run is taken.
    7163\item During the data runs, interlaced calibration events are taken at a rate of 50\,Hz.
    7264\end{itemize}
    7365
    74 We would like to continue taking the interlaced calibration events when a GRB
    75 alert is launched, but leave out the pedestal and calibration run in order not to loose valueable time.
     66We would like to continue taking the interlaced calibration events when a GRB alert is launched, but leave out the pedestal and calibration run in order not to loose valuable time.
    7667
    7768\subsection{Determine the maximum zenith angle}
    7869
    79 We determine the maximum zenith angle for GRB observations by requiring that the overwhelming majority of
    80 possible GRBs will have an in principle observable spectrum. Figure~\ref{fig:grh}
    81 shows the gamma-ray horizon (GRH) as computed in~\cite{KNEISKE}. The GRH is defined as the
    82 gamma-ray energy at which a part of $1/e$ of a hypothiszed mono-energetic flux gets absorbed after
    83 travelling a distance of $d$, expressed in redshift $z$ from the earth. One can see that at typical
     70We determine the maximum zenith angle for GRB observations by requiring that the overwhelming majority of possible GRBs will have an in principle observable spectrum. Figure~\ref{fig:grh}
     71shows the gamma-ray horizon (GRH) as computed in~\cite{KNEISKE}. The GRH is defined as the
     72gamma-ray energy at which a part of $1/e$ of a hypothiszed mono-energetic flux gets absorbed after
     73travelling a distance of $d$, expressed in redshift $z$ from the earth. One can see that at typical
    8474GRB distances of $z=1$, all gamma-rays above 100\,GeV get absorbed before they reach the earth.
    8575\par
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