Index: /trunk/MagicSoft/GRB-Proposal/GRB_proposal_2005.tex =================================================================== --- /trunk/MagicSoft/GRB-Proposal/GRB_proposal_2005.tex (revision 6123) +++ /trunk/MagicSoft/GRB-Proposal/GRB_proposal_2005.tex (revision 6124) @@ -89,4 +89,5 @@ \include{Timing} \include{Requirements} +\include{Tests} %------------------------------------------------------------ Index: /trunk/MagicSoft/GRB-Proposal/Strategies.tex =================================================================== --- /trunk/MagicSoft/GRB-Proposal/Strategies.tex (revision 6123) +++ /trunk/MagicSoft/GRB-Proposal/Strategies.tex (revision 6124) @@ -1,34 +1,34 @@ \section{Proposed Observation Strategies} -First of all let's consider how many observations are we going to do.\\ +First, we make an estimate of how many observations we will perform.\\ -A rough estimation of the time consume due to GRB observation comes out -from the claimed GRB observation by SWIFT, of about 150-200 GRBs/year, and -the results on the studies on the MAGIC duty-cycle made by -Nicola Galante \cite{GALANTE} and Satoko Mizobuchi \cite{SATOKO}. +A rough estimate of the needed observation time for GRBs derives +from the claimed GRB observation frequency of about 150-200 GRBs/year by the SWIFT +collaboration~\cite{SWIFT} and the results of the studies on the MAGIC duty-cycle +made by Nicola Galante~\cite{NICOLA} and Satoko Mizobuchi~\cite{SATOKO}. Considering a MAGIC duty-cycle of about 10\% and a tolerance of 5 hours to point the GRB, we should be able to point about 1-2 GRB/month. + + Such duty-cycle studies, made before MAGIC started its observations, -are reliable as long as weather constraints that were considered +are reliable as long as the considered weather constraints (~maximum wind speed of 10 m/s, maximum humidity of 80\% and -darkness at astronomical horizon~) revealed similar to the real ones that -are affecting MAGIC's observation time. In this duty-cycle study -also full moon night are considered useful (~just requiring +darkness at astronomical horizon~) remain similar to the real ones in 2005. +In these duty-cycle studies also full-moon nights were considered (requiring a minimum angular distance of the GRB from the moon of 30$^\circ$~), -while 3-4 nights per month are actually skipped because of full moon, -but this reduction of the real duty-cycle is about compensated -by the tolerance of 5 hours for considering the alert -(~5 hours more before the beginning of the night useful -for getting GRB's alerts are equivalent to an increase -of the duty-cycle of about 6 days per month~). Actually -observation's interruptions due to technical tasks are -not considered here. \\ +while we propose here to skip the 3-4 full moon nights per month which are not +yet under observational control. -All this discussion tells us that, excluding from our -considerations interruptions of the observing time due to -technical tasks, MAGIC should employ 1-2 nights per month -in GRB observations. This means that we must do as much -as possible to observe them EVERY time that a useful -alert occurs. +This reduction of the real duty-cycle w.r.t. the studies~\cite{NICOLA,SATOKO} +gets compensated by the tolerance of 5 hours for considering the alert observable +(5 hours more before the beginning of the night +are equivalent to an increase of the duty-cycle of about 6 days per month). +Observation interruptions due to technical shifts are not considered here. \\ + +To conclude, we ask here for about 1-2 nights per month for GRB observations, half-moon nights +included. +Moreover, as the chances go linear with the time that the telescope is able to follow +alerts, we ask do an effort as much as possible to maintain the telescope in alarm position +EVERY time that a GRB follow-up can be considered possible. \subsection{What to do with the AMC ? } @@ -36,15 +36,16 @@ \ldots {\bf MARKUS G. } \ldots -\subsection{What to do with moon shine ? } +\subsection{GRB observations in case of moon shine} +{\it gspot} allows only GRBs with an angular distance of $> 30^\circ$ from the moon. The telescope's slewing in case of a GRB alert will be done without closing the camera lids, so that the camera could be -flashed by the moon during such movement. In principle +flashed by the moon during such a movement. In principle a fast moon-flash shouldn't damage the PMTs, but the behaviour -of the camera and of the Camera Control {\it guagua} must -be tested. On the other hand,, if such test concludes that it is not safe -at all to get even a short flash from the moon, the possibility -to implement a new feature into the Steering System which -follow a different path while slewing must be considered. +of the camera and the Camera Control {\it La Guagua} must +be tested. On the other hand,, if such test conclude that it is not safe +to get even a short flash from the moon, the possibility +to implement a new feature into the Steering System must be considered +which follow a path around the moon while slewing. \par There was a shift observing the Crab-Nebula with half-moon at La Palma in December 2004. @@ -52,19 +53,19 @@ currents higher than 2\,$\mu$A. This means that moon-periods can be used for GRB-observations without fundamental modifications except for full-moon periods. We want to stress that -these periods increase the chances to catch GRBs by 80\%, even if full-moon observations are excluded -\cite{NICOLA}. +these periods increase the chances to catch GRBs by 80\%, even if full-moon observations are excluded~\cite{NICOLA}. It is therefore mandatory that the shifters keep the camera in fully operational conditions with high-voltages -already switched on from the beginning of a half-moon night until the end. +switched on from the beginning of a half-moon night until the end. This includes periods where no other half-moon +observations are scheduled. \par Because the background is higher with moon-light, we want to decrease then the maximun zenith angle from $\theta^{max} = 70^\circ$ to $\theta^{max} = 65^\circ$. -\subsection{Calibration } +\subsection{Calibration} For ordinary source observation, the calibration is currently performed in the following way: \begin{itemize} -\item At the beginning of the source observation, a dedicated pedestal run following by a calibration run is +\item At the beginning of the source observation, a dedicated pedestal run followed by a calibration run is taken. -\item During the data runs, interlaced calibration events are taken with a rate of 50\,Hz. +\item During the data runs, interlaced calibration events are taken at a rate of 50\,Hz. \end{itemize} @@ -74,13 +75,13 @@ \subsection{Determine the maximum zenith angle} -We determine the maximum zenith angle by requiring that the overwhelming majority of -possible GRBs will yield an in principle observable spectrum. Figure~\ref{fig:grh} +We 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} shows the gamma-ray horizon (GRH) as computed in~\cite{KNEISKE}. The GRH is defined as the -gamma-ray energy at which a part of $1/e$ of a hypothiszed mono-energetic flux is absorbed after +gamma-ray energy at which a part of $1/e$ of a hypothiszed mono-energetic flux gets absorbed after travelling a distance of $d$, expressed in redshift $z$ from the earth. One can see that at typical GRB distances of $z=1$, all gamma-rays above 100\,GeV get absorbed before they reach the earth. \par Even the closest GRB with known redshift ever observed, GRB030329~\cite{GRB030329}, lies at a redshift -of $z=0.1685$. In this case, gamma-rays above 200\,GeV get absorbed. +of $z=0.1685$. In this case, gamma-rays above 200\,GeV get entirely absorbed. \begin{figure}[htp] @@ -92,5 +93,7 @@ \par -We assume now an energy threshold of 50\,GeV for MAGIC at a zenith angle of $\theta = 0$. According +We assume now a current energy threshold of 50\,GeV for MAGIC at a zenith angle of $\theta = 0$\footnote{As +this proposal is going to be reviewed in a couple of months, improvements of the energy threshold will be taken +into account, then.}. According to~\cite{eckart}, the energy threshold of a Cherenkov telescope scales with zenith angle like: @@ -100,7 +103,9 @@ \end{equation} -Eq.~\ref{eq:ethrvszenith} leads to an energy threshold of about 900\,GeV at $\theta = 70^\circ$ and -500\,GeV at $\theta = 65^\circ$. Inserting these results into the GRH (figure~\ref{fig:grh}), one gets -a maximal observable GRB distance of $z = 0.1$ and $z = 0.2$, respectively. We think that the probability for +Eq.~\ref{eq:ethrvszenith} leads to an energy threshold of about 5.6\,TeV at $\theta = 80^\circ$, +900\,GeV at $\theta = 70^\circ$ and 500\,GeV at $\theta = 65^\circ$. +Inserting these results into the GRH (figure~\ref{fig:grh}), one gets +a maximal observable GRB distance of $z = 0.1$ at $\theta = 70^\circ$ and $z = 0.2$ at $\theta = 65^\circ$. +We think that the probability for GRBs to occur at these distances is sufficiently small in order to neglect the very difficult observations beyond these limits. @@ -108,7 +113,10 @@ \subsection{In case of follow-up: Next steps} -Analysis during day: -\par -If some significance is seen, observe the same position next night to get some OFF-data. +We propose to analyse the GRB data at the following day in order to tell whether a follow-up observation during +the next night is useful. We think that a limit of 3\,$\sigma$ significance should be enough to start such a +follow-up observation of the same place. This follow-up observation can then be used in two ways: - +\begin{itemize} +\item In case of a repeated outbursts for a longer time period of direct observation +\item In the other case for having Off-data at exactly the same location. +\end{itemize} Index: /trunk/MagicSoft/GRB-Proposal/Tests.tex =================================================================== --- /trunk/MagicSoft/GRB-Proposal/Tests.tex (revision 6124) +++ /trunk/MagicSoft/GRB-Proposal/Tests.tex (revision 6124) @@ -0,0 +1,4 @@ +\section{Calibrations and Tests} + +{\ldots \it \bf Crab data at different axis-offsets to calibrate off-axis sensitivity \ldots \\} +