Changeset 6124 for trunk/MagicSoft

Timestamp:

01/30/05 11:10:59 (20 years ago)

Author:

gaug

Message:

*** empty log message ***

Location:

trunk/MagicSoft/GRB-Proposal

Files:

• GRB_proposal_2005.tex (modified) (1 diff)
• Strategies.tex (modified) (7 diffs)
• Tests.tex (added)

trunk/MagicSoft/GRB-Proposal/GRB_proposal_2005.tex

@@ -89 +89 @@
 \include{Timing}
 \include{Requirements}
+\include{Tests}
 %------------------------------------------------------------
 

trunk/MagicSoft/GRB-Proposal/Strategies.tex

@@ -1 +1 @@
 \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 +36 @@
 \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 +53 @@
 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 +75 @@
 \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 +93 @@
 
 \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 +103 @@
 \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 +113 @@
 \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}