Index: /trunk/MagicSoft/GRB-Proposal/GRB_proposal_2005.tex =================================================================== --- /trunk/MagicSoft/GRB-Proposal/GRB_proposal_2005.tex (revision 6549) +++ /trunk/MagicSoft/GRB-Proposal/GRB_proposal_2005.tex (revision 6550) @@ -58,6 +58,7 @@ \author{N. Galante\\ \texttt{}\\ M. Garczarczyk\\ \texttt{}\\ - M. Gaug\\ \texttt{} \\ - S. Mizobuchi\\ \texttt{} + M. Gaug\\ \texttt{}\\ + S. Mizobuchi\\ \texttt{}\\ + D. Bastieri\\ \texttt{} } Index: /trunk/MagicSoft/GRB-Proposal/Introduction.tex =================================================================== --- /trunk/MagicSoft/GRB-Proposal/Introduction.tex (revision 6549) +++ /trunk/MagicSoft/GRB-Proposal/Introduction.tex (revision 6550) @@ -3,14 +3,14 @@ \subsection{Observation of GRBs} -The \ma telescope's support structure and mirrors have been designed exceptionally light in order to -react quickly to GRB alerts from satellites. \cite{design} and~\cite{PETRY} set -the objective to turn the telescope to the burst position within 10-30\,sec. +The support structure and mirrors of the \ma telescope were designed to be exceptionally light in order to +react quickly to GRB alerts from satellites. The aim was to turn the telescope toward the burst position +within 30\,s~\cite{design,PETRY}, in order to have a fair chance to detect a burst when the prompt $\gamma$--emission is still ongoing. -During the commissioning phase, it could be proven that our goal was reached. -The telescope is able to turn 180\,deg. in azimuth within 20\,sec. and 90\,deg. in zenith within 10\,sec.\\ +During the commissioning phase, it could be proven that the goal was achieved. +The telescope is able to turn $180^\circ$ in azimuth within 20\,s and $90^\circ$ in zenith within 10\,s.\\ Very high energy (VHE) GRB observations have the potential to constrain the current GRB models -on both prompt and extended phases of GRB emission~\cite{HARTMANN,MANNHEIM}. -Models based on both internal and external shocks predict VHE gamma-ray fluences comparable to, +on both the prompt and the extended phase of GRB emission~\cite{HARTMANN,MANNHEIM}. +Models based on either internal or external shocks predict VHE gamma-ray fluences comparable to, or in certain situations stronger than, the keV-MeV radiation, with durations ranging from shorter than the keV-MeV burst to extended TeV @@ -19,10 +19,10 @@ \par -In many publications, the possibility has been explored that more energetic $\gamma$-rays come along with the -(low-energy) GRB. Proton-synchrotron emission~\cite{TOTANI} have been suggested -as well as photon-pion production~\cite{WAXMAN,BOETTCHER} and inverse-Compton scattering +Many publications foresee that high-energy $\gamma$-rays can come along with the +(low-energy) GRB. Possible causes range from proton-synchrotron emission~\cite{TOTANI} to +photon-pion production~\cite{WAXMAN,BOETTCHER} to inverse-Compton scattering in the burst environment~\cite{MESZAROS93,CHIANG,PILLA,ZHANG2,BELOBORODOV}. -Long-term high energy (HE) $\gamma$-emission from accelerated protons in the -forward-shock has been predicted in~\cite{LI}. +A long-term high energy (HE) $\gamma$-emission can come from accelerated protons in the +forward-shock, as predicted in~\cite{LI}. This model predicts GeV inverse Compton emission even one day after the burst. Even considering pure electron-synchrotron radiation, measurable GeV-emission for a significant @@ -38,9 +38,10 @@ \par -Several attempts have been made in the past to observe GRBs in the GeV range, +Several attempts were made in the past to observe GRBs in the GeV range, each indicating some excess over background but without stringent evidence. -The only significant detection was performed by \eg which was able to observe seven GRBs -emitting HE -photons in the 100\,MeV to 18\,GeV range~\cite{EGRET, DINGUS1}. The data shows no evidence of a HE cut-off in the GRB spectrum~\cite{DINGUS2}. Recent results indicate that the spectrum of some GRBs contains a very hard, luminous, long-duration component~\cite{GONZALES}. +The only significant detection was performed by \eg, that was able to observe seven GRBs +emitting HE photons with energies between 100\,MeV and 18\,GeV~\cite{EGRET, DINGUS1}. +The data shows no evidence of a HE cut-off in the GRB spectrum~\cite{DINGUS2}. +Recent results indicate that the spectrum of some GRBs contains a very hard, luminous, long-duration component~\cite{GONZALES}. There have been results suggesting gamma rays beyond the GeV range from the TIBET air shower array in coincidence with BATSE bursts~\cite{AMENOMORI}, rapid follow-up observations by the @@ -52,17 +53,17 @@ producing a spectral index of $-1$ with no cut-off up to the detector energy limit at 200\,MeV.\\ -Concerning estimates of the \ma GRB observability, a study of GRB spectra obtained from the -third and fourth \ba catalogue has been made in~\cite{ICRC,NICOLA}. The spectra were extrapolated to GeV -energies with a simple continuation of the observed high-energy power law behaviour and the calculated -fluxes compared with \ma sensitivities. Setting conservative cuts on observation times and significances, +To estimate the observability of GRB by \ma, sources of the +third and fourth \ba catalogue were studied~\cite{ICRC,NICOLA}. Their spectra were extended to GeV +energies with a simple power-law and using the observed high-energy spectral index: the extrapolated fluxes +were at last compared with \ma sensitivities. Setting conservative cuts on observation times and significances, and assuming an energy threshold of 15~GeV, a 5\,$\sigma$-signal rate of $0.5-2$ per year -was obtained for an assumed observation delay between 15 and 60\,sec. and a \ba trigger rate -($\sim$\,360/year). As the \sw alert rate is about factor~2 lower, including even fainter bursts than +was obtained for an assumed observation delay between 15 and 60\,s and a \ba trigger rate +($\sim$\,360/year). As the \sw alert rate is about a factor~2 lower, including even fainter bursts than those observed by \ma, this number still have to be lowered. Taking into account the local rate of GRBs estimated in~\cite{GUETTA}, late afterglow emission from a few tens of GRBs per year should be observable over the whole sky above our energy threshold. -The model of~\cite{ASAF2} predict delayed GeV-emission that should be significantly detectable by \ma -in 100\,sec. +The model of~\cite{ASAF2} predicts delayed GeV-emission that should be significantly detectable by \ma +in 100\,s. \subsection{Observation of XRFs} @@ -75,5 +76,5 @@ Alternatively, an increase of the baryon load within the fireball itself~\cite{HUANG} or low efficiency shocks~\cite{BARRAUD} could produce XRFs. -If there is a connection between XRFs and GRBs, they should originate at rather low redshifts (z $<$ 0.6) +If there is a connection between XRFs and GRBs, they should originate at rather low redshifts ($z < 0.6$) because otherwise, the XRF energies would not fit into the observed correlation between GRB peak energy and isotropic energy release~\cite{LEVAN}. \\ @@ -92,15 +93,13 @@ periodically emit $\gamma$-rays. Only four identified SGRs were discovered in the last 20 years: SGR0526-66, SGR1806-20, SGR1900+14, SGR1627-41. -GRBs and SGRs can be explained within one same gamma jet model where the jet is observed at different -beam-angles and at different ages~\cite{FARGION}.\\ +GRBs and SGRs can be explained within the same gamma jet model where the jet is observed at different +beam-angles and different times~\cite{FARGION}.\\ -The BAT instrument on the SWIFT satellite triggered on an outburst from SGR1806-20 on 30. January 2005. +The BAT instrument on the SWIFT satellite triggered on an outburst from SGR1806-20 on January $30^{\mathrm{th}}$, 2005. The fluence was about $10^{-5}$\,erg/cm$^2$ in the range between 15 and 350\,keV. This event was five orders of magnitude smaller than the giant flare from this source on the -December 27$^{th}$, 2004~\cite{GCN3002}. MAGIC have a enough sensitivity for observing the event which have a fluence more than 2.5 $\times$ 10 $^{-2}$ erg/cm$^{2} \cdot$\,sec at 100\,keV, when power law index of -2.0 and 100 sec. observation time are assumpted. Therefore if a giant flare from SGR occurs as SGR1806-20, MAGIC would be able to detect the $\gamma$-ray emission from these source. - - - - +December 27$^{\mathrm{th}}$, 2004~\cite{GCN3002}. +MAGIC has enough sensitivity for observing events with fluences bigger than $2.5 \times 10^{-2}\mathrm{erg}\cdot\mathrm{cm}^{-2}\mathrm{s}^{-1}$ at 100\,keV, when a spectral index of $-2.0$ and 100\,s of observation time are assumed. +Therefore if an SGR as the giant flare of SGR1806-20 occurs, MAGIC would be able to detect its $\gamma$-ray emission. %%% Local Variables: Index: /trunk/MagicSoft/GRB-Proposal/Monitor.tex =================================================================== --- /trunk/MagicSoft/GRB-Proposal/Monitor.tex (revision 6549) +++ /trunk/MagicSoft/GRB-Proposal/Monitor.tex (revision 6550) @@ -136,12 +136,14 @@ \subsection{Experience from SWIFT GRBs until now} -According to the \sw home page~\cite{SWIFT}, the satellite has detected 12 GRBs since mid-December last year. -The bursts were detected by chance during the commissioning phase. The satellite did not send -the coordinates to the \g on time. The current sample contains two bursts -which could have been observed by \ma:\\ +According to the \sw home page~\cite{SWIFT}, the satellite has detected 16 GRBs since mid-December last year. +The bursts were detected by chance during the commissioning phase. Since 15th of February the satellite sends +burst allerts to the \g in real time. The current sample contains three bursts +which could have been observed by \ma. The coordinates of the last burst from 15th February were send via an +alert within few seconds. The weather conditions did not allow any observation in this nights.\\ \begin{tabular}{lllcc} 19th & December & 2004 & 1:42 am & Zd $\sim 65^\circ$ \\ -26th & December & 2004 & 20:34 am & Zd $\sim 52^\circ$ \\ \\ +26th & December & 2004 & 8:34 pm & Zd $\sim 52^\circ$ \\ +15th & Februar & 2005 & 2:33 am & Zd $\sim 17^\circ$ \\ \\ \end{tabular} @@ -212,215 +214,2 @@ %%% TeX-master: "GRB_proposal_2005" %%% End: -\section{The Burst Alarm System at La Palma} - -{\bf Current status:} - -\par - -The Burst Alarm System {\it gspot} (Gamma -Sources Pointing Trigger) is working in La Palma since last summer. -It performs a full-time survey of the {\it GRB Coordinates Network} (\g) alerts~\cite{GCN}. -Different satellite experiments -send GRB coordinates to the \g which distributes -the alerts to registered users. -The Burst Alarm System is composed of a core program which -manages the monitoring of the \g and the communication with the Central Control (CC). -It also handles three communication channels to notice the shifters -about an alert. It is a C based daemon running 24 -hours a day on the {\it www} machine, our external server, in a -{\it stand alone} mode. It does not need to be operated and is -fully automatic. It manages network disconnections -within the external net and/or the internal one. - - -\subsection{The Connection to the GCN} - -The connection to the \g is performed by {\it gspot} through a -TCP/IP connection to a computer at the Goddard Space Flight Center (GSFC). -This computer distributes the alerts from the satellite -experiments through an internet socket connection. {\it gspot} -acts as a server while the client, running at the GSFC, -manages the communication of the data concerning the GRBs -and concerning the status of the connection. \\ - -The format of the data distributed through the \g differ between the individual satellites -and the kind of package. Currently, three satellites participate in the GRB survey: -HETE-2~\cite{HETE}, INTEGRAL~\cite{INTEGRAL} and SWIFT~\cite{SWIFT}. -The alerts include the UTC, the GRB coordinates (not always), error on coordinates -(not always) and intensity (photon counts) of the burst. -The first notices from HETE-2 and INTEGRAL usually do not include the coordinates. -In few cases only coordinates are distributed in refined notices. -The \sw alerts are predicted to arrive with coordinates between 30-80 sec after the onset of the burst. -The error on the coordinates from the BAT detector will be 4 arcmin which is smaller than the size of one -inner pixel of the \ma camera.\\ - -In case of alert, {\it gspot} stores the informations and enters -an {\bf Alarm State}. The duration of the alarm depends on the following parameters: - -\begin{itemize} -\item {\bf Darkness of the sky}: The Sun has to be below -the astronomical horizon or have a zenith angle larger than 108$^\circ$. -\item {\bf Position of GRB}: The GRB equatorial -coordinates are transformed into local horizontal coordinates. -The resulting GRB zenith angle has to be smaller than 70$^\circ$. If the Moon is -shining, the maximal zenith angle is reduced to 65$^\circ$. -\item {\bf Position of Moon}: The angular -distance from the GRB to the moon has to be at least 30$^\circ$. -\end{itemize} - -If one or more of these conditions fail, {\it gspot} enters into a -{\color[rgb]{0.9,0.75,0.}\bf Yellow Alarm State}: The GRB is not observable at the moment. -Currently, the program does not calculate if and when the GRB will become observable for \ma. -If all the mentioned conditions are satisfied, -{\it gspot} enters into a \textcolor{red}{\bf Red Alarm State}, meaning that the GRB is observable.\\ - -In both cases (\textcolor{red}{\bf RED} or {\color[rgb]{0.9,0.75,0.}\bf YELLOW} Alarm State), {\it gspot} establishes the communication with the CC and sends the GRB equatorial coordinates (RA/DEC J2000). -For the communication with CC the format defined in~\cite{CONTROL} is used. At the same time, -the shifters and the GRB-MAGIC group is contacted. - -\subsection{The Interface to the Central Control} - -An interface of {\it gspot} sends all the relevant information to the CC. -When {\it gspot} is not in alarm state, standard packages are continuously exchanged between CC and {\it gspot}. -These packages contain the main global status of the two subsystems. -In case of alert, {\it gspot} starts to send special alert packages to the CC, -containing information about the GRB and the ``color'' of the alert. -The exchange of the alert packages continues until: - -\begin{itemize} -\item {\it gspot} receives from the CC the confirmation -that the alert notice has been received; The CC must send back the alert in order -to perform a cross-check of the relevant data. -\item the alarm state expires after {\bf 5 hours} -\end{itemize} - -The CC informs the shift crew about the alert and undertakes -further steps only in case of a \textcolor{red}{\bf red alerts}. -In this case, a pop-up window -appears with all the alert information received by the burst monitor. -The operator has to confirm the notice by closing the pop-up window. -He can decide whether to stop the current scheduled observation and to point the GRB. -A new button will be displayed in the CC allowing to point the telescope to -the GRB coordinates. - -\subsection{GRB Archive and Emails to the GRB-mailing List} - -In case of alert -- even if it did not contain the necessary coordinates -- the -information is translated into ``human language'' and stored in ASCII files. -At the same time, an e-mail is sent to the MAGIC GRB-mailing list -{\it grb@mppmu.mpg.de}. - -\subsection{The GRB Web Page} - -The status of the GRB Alert System and relevant informations about the latest -alerts are displayed on a separate web page. The page is hosted at the web server in La Palma a -and can be accessed under:\\ - -\qquad \qquad http://www.magic.iac.es/site/grbm/\\ - -The web page updates itself automatically every 10 seconds. In this way -the status of the Burst Alarm System can be checked by the shifters and from outside. - -\subsection{The Acoustic Alert} - -A further CC-independent acoustic alarm called {\it phava} -(PHonetic Alarm for Valued Alerts) will be installed -in La Palma soon. It will provide a loud acoustic signal -even if the CC is switched off, so that persons in the counting house -can be noticed about the alert situation. The signal will be on as long as -{\it gspot} remains in alarm state for a minimum of 1 minute. -The device features also a display with the status of the system and the alert. - -\subsection{Summary of Alerts Received Until Now} - -Since July 15$^{\mathrm{th}}$, 2004, {\it gspot} has been working stably at La Palma. -It received about 100 alerts from HETE-2 and INTEGRAL, out of which -21 contained GRB's coordinates. Time delays to the onset of the burst -were of the order of several minutes to tens of minutes. The Burst Monitor can be considered stable -since November, 2004. Since then, we have received the following two significant alerts:\\ - -\begin{tabular}{lllcccl} -19th & December & 2004 & 1:44 am & INTEGRAL satellite & Zd $\sim 60^\circ$ & Time delay 71 sec.\\ -28th & January & 2005 & 5:36 am & HETE-2 satellite & Zd $\sim 65^\circ$ & Time delay 73 min. \\ \\ -\end{tabular} - -In both cases the weather conditions at La Palma were bad. - -\subsection{Experience from SWIFT GRBs until now} - -According to the \sw home page~\cite{SWIFT}, the satellite has detected 12 GRBs since mid-December last year. -The bursts were detected by chance during the commissioning phase. The satellite did not send -the coordinates to the \g on time. The current sample contains two bursts -which could have been observed by \ma:\\ - -\begin{tabular}{lllcc} -19th & December & 2004 & 1:42 am & Zd $\sim 65^\circ$ \\ -26th & December & 2004 & 20:34 am & Zd $\sim 52^\circ$ \\ \\ -\end{tabular} - -\subsection{Comparison between the Satellite Orbits} - -Figure~\ref{fig:orbit} shows the orbits of the \sw, \he and \ig satellites. -The \sw and \he satellites are situated in a circular orbit with -20.6$^\circ$ and 2$^\circ$ inclination, respectively. -One revolution of the \sw and \he satellites last about 100\,min. -The \ig satellite has a -highly eccentric orbit with a revolution period of three sidereal days around the Earth. - -\par - -It is difficult to draw strong conclusions from the individual satellites' orbits. -The orientation of the satellites' FOV is influenced by the scheduled targets. -However, \sw is the satellite with the largest inclination and overlaps mostly with the FOV of \ma. -This increases the chance to receive {\bf Red Alarms} from this satellite. - -\begin{figure}[htp] -\centering -\includegraphics[width=0.7\linewidth]{GCNsatellites.eps} -\caption{Orbits of the \sw (top), \he (center) and \ig (bottom) satellites: The pointed lines -show the orbit while the drawn lines show the horizon of the Sun. Here, a typical night at -La Palma is shown. The \sw satellite passes over the Roque seven times each night.} -\label{fig:orbit} -\end{figure} - -\subsection{Routines to Be Defined} - -The Burst Alarm System is currently able to provide the minimum -features needed to point and to observe a GRB. However, in order to improve the efficiency -to point and observe GRBs, several procedures have to be defined: - -\begin{itemize} -\item {\bf Yellow Alarm strategy}: -The strategy to follow a {\bf Yellow Alarm} is not defined yet. -In such a case, the CC does not undertake any steps, -except confirming the alarm notice to the Burst Monitor. We have not -calculated yet if and when the GRB will become observable. -It would make sense to check if we could point to the burst during the period of 5 hours. -The Alarm System should change to a {\bf Red Alarm State}, then. - -\item {\bf Sequence of alerts}: -How to deal with new alerts that are distributed during the time -that {\it gspot} is in alarm state? Currently, {\it gspot} -locks its alert status until it exits the alarm state (see session 2.2). -This feature was implemented to avoid any loss of GRB information. -Such a situation can occur for example if more than one burst alert is sent before -the shift crew launches the CC. -To solve this problem, we will change the {\it gspot} routine -by implementing a list of all available GRB alerts. - - -\par - -If more than one alert is present in the list, the program -will weight the possible GRBs according to the following criteria: -(1) the total time of observability within the canonical 5 hours, -(2) the intensity of the burst and -(3) the time until the GRB becomes observable. -The information of the best GRB will be sent to the CC. - -\end{itemize} - -%%% Local Variables: -%%% mode: latex -%%% TeX-master: "GRB_proposal_2005" -%%% End: Index: /trunk/MagicSoft/GRB-Proposal/Requirements.tex =================================================================== --- /trunk/MagicSoft/GRB-Proposal/Requirements.tex (revision 6549) +++ /trunk/MagicSoft/GRB-Proposal/Requirements.tex (revision 6550) @@ -3,5 +3,5 @@ In the previous sessions we described the status and tasks we still plan to do in order to complete the GRB Alarm System. -Parallel to our system also the different subsystems of the MAGIC telescope have +At the same time, also the other different subsystems of the MAGIC telescope have to implement and test strategies for the GRB survey. @@ -12,8 +12,8 @@ to make a one week shift where the experts meet and test the GRB strategies. In order to avoid good observation time we suggest to make the shift -during a moon period. This shift should take place, in arrangement with the +during a Moon period. This shift should take place, in arrangement with the different subsystem managers, before April this year. The time limitation is -based on the moment when SWIFT will finish its comissioning phase. The sattelite -started mid of February to send alerts in real time to the ground stations. +based on the moment when SWIFT will start to work fully automatically and send +alerts in real time to the ground stations. \par @@ -26,12 +26,12 @@ One of the most important issues is to implement and test the fast slewing capability -of the telescope. Especially the communication between CC and Cosy has still to be implemented for +of the telescope. In particular, the communication between CC and Cosy has still to be implemented for the case of fast movements. \item {\bf Use of look-up tables:}\ -The use of look-up tables to correct the mirror focus during the movement to the GRB +The use of look-up tables to correct the mirror focus during the slewing to the GRB coordinates is desirable. In the alert situation it is a waste of time if we would have to -close the camera lids and carry out the full laser adjustment (\~5~min) before starting the observation. +close the camera lids and carry out the full laser adjustment ($\sim 5$~min) before starting the observation. The reproducibility of the focus with the use of look-up tables has to be proven. In case of using lookup-tables during the slewing, it is necessary to change the protocol between the AMC and CC. @@ -39,10 +39,10 @@ \item {\bf Behaviour of the camera during moon:}\ -It has to be checked what happens when during the pointing to a GRB position the telescope move over the -moon. It is excluded by the GRB Alert System that a burst closer than 30$\deg$ to the moon will be pointed. -However, it can happen that during the movement of the telescope the moon will pass the FOV. +It has still to be checked what happens when the telescope points directly at the Moon while +slewing toward a new position. The GRB Alert System prevents a burst closer than $30^\circ$ +from the Moon to be pointed. +However, it can happen that during the movement of the telescope the Moon will enter the FoV. In this case the HV of the PMTs will be reduced automatically and will not increase fast enough for the GRB observation. - \end{itemize} Index: /trunk/MagicSoft/GRB-Proposal/Strategies.tex =================================================================== --- /trunk/MagicSoft/GRB-Proposal/Strategies.tex (revision 6549) +++ /trunk/MagicSoft/GRB-Proposal/Strategies.tex (revision 6550) @@ -28,11 +28,11 @@ In these duty-cycle studies also full-moon nights were considered (requiring -a minimum angular distance between the GRB and the moon of 30$^\circ$) yielding in -total 10\%. +a minimum angular distance between the GRB and the Moon of 30$^\circ$) yielding a +total of 10\%. \par The duty-cycle in~\cite{NICOLA} will be increased by taking into account that \ma should also observe the -afterglow emission of an burst that occurred up to 5 hours before the start of the shift. +afterglow emission of a burst that occurred up to 5 hours before the start of the shift. The afterglow observation is equivalent to an increase of the duty-cycle of about 6 days per month. However, taking off the full-moon time, we remain with the anticipated 10\%.\\ @@ -51,9 +51,9 @@ 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} +majority of possible GRBs will have in principle an observable spectrum. Figure~\ref{fig:grh} shows the gamma-ray horizon (GRH) as computed in~\cite{KNEISKE,SALOMON}. The GRH is defined as the -gamma-ray energy at which a part of $1/e$ of a hypothetical mono-energetic flux gets absorbed after +gamma-ray energy at which a fraction of $1/\mathrm{e}$ of a hypothetical mono-energetic flux gets absorbed after travelling a distance, expressed in redshift $z$, from the source. One can see that at typical -GRB distances of $z=1$, all gamma-rays above 100\,GeV get absorbed before they can reach the earth. +GRB distances of $z=1$, all gamma-rays above 100\,GeV get absorbed before they can reach the Earth. \par @@ -75,5 +75,5 @@ \begin{equation} -E_{thr}(\theta) = E_{thr}(0) \cdot \cos(\theta)^{-2.7} +E_{thr}(\theta) = E_{thr}(0) \cdot (\cos\theta)^{-2.7} \label{eq:ethrvszenith} \end{equation} @@ -88,26 +88,24 @@ \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 +{\it gspot} allows only GRBs with an angular distance of $> 30^\circ$ from the Moon. +Telescope 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 a movement. In principle -a fast moon-flash shouldn't damage the PMTs, but the behaviour +flashed by the Moon during such movement. In principle, +a fast Moon flash should not damage the PMTs, but the behaviour of the camera and the Camera Control {\it La Guagua} must be tested. On the other hand, if such tests 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. +to get even a short flash from the Moon, the Steering System, while slewing, +will have to follow a path around the Moon. \par -There was a shift observing the Crab-Nebula with half-moon at La Palma in December 2004. -That experience showed that the nominal HV could be maintained and gave no -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\%. +In December 2004, the shift in La Palma observed the Crab-Nebula even during half-moon. +During the observation, the nominal HV could be maintained while the currents were kept below +2\,$\mu$A. This means that only full-moon periods are not suitable for GRB-observations. +We want to stress the fact that observations at moon-time increase the chances to catch GRBs by 80\%. It 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 those periods, the telescope should be pointed +If no other data can be taken during those periods, the telescope should be pointed to a Northern direction, close to the zenith. This increases the probability to overlap with the FOV of \sw. @@ -115,6 +113,6 @@ \par -Because of higher background with moon-light, we suggest to decrease the maximum zenith angle from -$\theta_{max} = 70^\circ$ to $\theta_{max} = 65^\circ$, there. +In these conditions, because of higher background with moon-light, we suggest to decrease the maximum zenith angle from +$\theta_{max} = 70^\circ$ to $\theta_{max} = 65^\circ$. \subsection{Active Mirror Control Behaviour} @@ -142,5 +140,5 @@ \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 sky location. +\item Or else, for having off-data at exactly the same sky location. \end{itemize} Index: /trunk/MagicSoft/GRB-Proposal/Timing.tex =================================================================== --- /trunk/MagicSoft/GRB-Proposal/Timing.tex (revision 6549) +++ /trunk/MagicSoft/GRB-Proposal/Timing.tex (revision 6550) @@ -8,6 +8,6 @@ Different models predict prompt and delayed HE $\gamma$-ray emission. -Most of them predict HE photons parallel to the keV-MeV burst, -but also delayed emission is possible. +Most of them predict HE photons to be simultaneous with the keV-MeV burst, +but also a delayed emission is possible. Our main goal should be to observe the GRB location as quickly as possible. However, in order to confirm or rule out different predictions, @@ -53,8 +53,12 @@ Based on the model in~\cite{DERISHEV}, three different components of VHE emission exists in an GRB. -The corresponding components are illustrated in figure~\ref{fig:timeline}. -(a) There is the prompt 100\,GeV peak before and during the first keV-MeV peak, -(b) the VHE emission due to Inverse Compton scattering lasting for the whole duration of the GRB pulse and -(c) the reprocessed Inverse Compton emission which may last up to hours after the GRB onset. +The corresponding components are illustrated in figure~\ref{fig:timeline}. +\renewcommand{\theenumi}{\alph{enumi}} +\begin{enumerate} +\item There is the prompt 100\,GeV peak before and during the first keV-MeV peak, +\item the VHE emission due to Inverse Compton scattering lasting for the whole duration of the GRB pulse and +\item the reprocessed Inverse Compton emission which may last up to hours after the GRB onset. +\end{enumerate} +\renewcommand{\theenumi}{\arabic{enumi}} (b) and (c) are the components which may be detectable by \ma and other ground based $\gamma$-ray detectors. @@ -66,6 +70,6 @@ \begin{equation} B_{min} \sim \frac{5\times10^{-2}}{\Gamma^{3}}\, - \frac{\epsilon_{2ph}}{1TeV}\, - \frac{t_{GRB}}{10s}\, G + \frac{\epsilon_{2ph}}{1\,\mathrm{TeV}}\, + \frac{t_{\mathrm{GRB}}}{10\,\mathrm{s}}\,\mathrm{G} \label{eq:minimal} \end{equation} @@ -73,5 +77,6 @@ If the magnetic field is much stronger than $B_{min}$, the delay of reprocessed photons may become observable. -For this perpendicular case it can be calculated via the following asymptotic expression: +Taking into account only the components of $B$ orthogonal to the electron path, +the delay can be calculated via the following asymptotic expression: \begin{equation} @@ -81,8 +86,8 @@ For typical values of the absorption threshold $\epsilon_{2ph}=1\,TeV$, -the duration time of GRB main pulse $t_{GRB}=10^{2}\,s$ and Lorentz factor of the GRB shell +the duration time of GRB main pulse $t_{\mathrm{GRB}}=10^{2}\,\mathrm{s}$ and Lorentz factor of the GRB shell $\Gamma=10^{2}$, the duration of delayed VHE emission will be 0.8 hours for the component of magnetic -field perpendicular to electron's trajectory $B_{\perp}=0.1\,Gauss$, -3.6 hours for $B_{\perp}=1.0\,Gauss$ and 17.3 hours for $B_{\perp}=10\,Gauss$.\\ +field perpendicular to electron's trajectory $B_{\perp}=0.1\,\mathrm{G}$, +3.6 hours for $B_{\perp}=1.0\,\mathrm{G}$ and 17.3 hours for $B_{\perp}=10\,\mathrm{G}$.\\ The observation of the delayed VHE emission and the time correlation will give informations @@ -95,8 +100,8 @@ constraints on model parameters of GRB sources.\\ -In the case of an \textcolor{red}{\bf Red Alarm}, we propose to take data for {\bf 5 hours}. +In case of a \textcolor{red}{\bf Red Alarm}, we propose to take data for {\bf 5 hours}. \par -In the case of an \textcolor{yellow}{\bf Yellow Alarm}, -we propose to observe the source from the time when it will become observable until the {\bf 5 hours} pass. +In case of a \textcolor{yellow}{\bf Yellow Alarm}, we propose to observe the source +from the time when it will become observable until {\bf 5 hours} after the GRB beginning. %%% Local Variables: