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01/29/05 17:26:54 (20 years ago)
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gaug
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  • trunk/MagicSoft/GRB-Proposal/Monitor.tex

    r6102 r6118  
    1111in their wide FOV and send immediately the coordinates of the GRBs to the GCN network.
    1212The network send the alerts to registered users and allows other satellites as well as
    13 ground based observatories to observe the GRBs and their afterglows at different wavelenghts.
    14 The Burst Alarm System is composed by a main program -
    15 the core of the system - which acts in two ways: on the
     13ground based observatories to observe the GRBs and their afterglows at different wavelengths.
     14The Burst Alarm System is composed by a core program -
     15which acts in two ways: on the
    1616one hand it manages the monitoring of the GCN, on the other it manages
    1717the communication with the Central Control (CC). Then it also manages
    1818three communication channels to notice the shifters
    19 about a alert situation. The program is called {\it gspot} (Gamma
     19about an alert situation. The program is called {\it gspot} (Gamma
    2020Sources POinting Trigger). It is a C based daemon running 24
    21 hours a day onto the {\it www} machine, our external server, in a
    22 {\it stand alone} mode. It do not need to be operated and is
    23 fully automatically able to manage network diconnections
     21hours a day on the {\it www} machine, our external server, in a
     22{\it stand alone} mode. It does not need to be operated and is
     23fully automatic. It manages network diconnections
    2424within the external net and/or the internal one.
    2525
     
    2727\subsection{The connection to GCN}
    2828
    29 The connection to GCN is performed by {\it gspot} through a
    30 TCP/IP connection within a computer at Goddard Space Flight
    31 Center (GSFC). This computer distributes the informations it is recieving from the satellite
    32 experiments through the normal internet socket connection. The {\it gspot} onto our
     29The connection to {\it GRB Coordinates Network} (GCN)~\cite{GCN} is performed by {\it gspot} through a
     30TCP/IP connection to a computer at the Goddard Space Flight Center (GSFC).
     31This computer distributes the information it recieves from the satellite
     32experiments through the normal internet socket connection. The {\it gspot} on our
    3333side acts as a server while the client, running at the GSFC,
    3434manages the communication of the data concerning the GRBs
    3535and concerning the status of the connnection. \\
    3636
    37 The format of the data distributed through GCN differ between the individual satellites
     37The format of the data distributed through the GCN differ between the individual satellites
    3838and the kind of package. There are three satellites participating in the GRB survey:
    3939HETE-2, INTEGRAL and SWIFT. All are sending alerts which include the
    4040UTC, coordinates (not always), error on coordinates
    4141(not always) and intensity (photon counts) of the burst.
    42 The first notice from HETE-2 and INTEGRAL usually do not include the coordinates.
    43 In only few cases coordinates are distibuted delayed in more refined notices.\\
     42The first notices from HETE-2 and INTEGRAL usually do not include the coordinates.
     43In few cases only coordinates are distributed in more refined notices.\\
    4444
    45 In case of an alert {\it gspot} stores the informations and enters into
    46 an {\bf Alarm State}. The duration of the alert state depends on the following parameters:
     45In case of an alert {\it gspot} stores the informations and enters
     46an {\bf Alarm State}. The duration of the alarm state depends on the following parameters:
    4747
    4848\begin{itemize}
     
    5050to the astronomical horizon of 108$^\circ$ zenith;
    5151\item {\bf position of GRB}, the GRB equatorial
    52 coordinates are transformed into local horizontal coordinates and comparised whether the
    53 GRB zenith angle is smaller than 70$^\circ$; in the case that moon is
    54 shining in the sky, we propose to reduce this zenith limith to 60$^\circ$;
    55 \item {\bf position of moon}, checking whether the angular
    56 distance from the GRB to the moon is at least 30$^\circ$.
     52coordinates are transformed into local horizontal coordinates.
     53The resulting GRB zenith angle has to be smaller than 70$^\circ$; in the case that the moon is
     54shining, this zenith angle limit is reduced to 65$^\circ$;
     55\item {\bf position of moon} The angular
     56distance from the GRB to the moon has to be at least 30$^\circ$.
    5757\end{itemize}
    5858
    59 If one or more of these conditions failed then {\it gspot}
     59If one or more of these conditions fail, {\it gspot}
    6060enters into a {\bf Yellow Alarm State}. It means that the GRB is not observable
    61 at the moment. Currently the program do not calculate if and when the GRB will
     61at the moment. Currently the program does not calculate if and when the GRB will
    6262become observable at La Palma.
    6363If all conditions mentioned above are satisfied,
     
    6565the GRB is considered to be observable at the current time.\\
    6666
    67 In both cases (in RED and YELLOW alarm state) {\it gspot} assamble the communication
    68 with the CC and sends the GRB equatorial coordinates (RA/DEC J2000).
    69 For the communication to CC the format defined in \cite{CONTROL} is used. In the same time
     67In both cases (in RED and YELLOW alarm state) {\it gspot} establishes the communication
     68with the Central Control and sends the GRB equatorial coordinates (RA/DEC J2000).
     69For the communication to CC the format defined in~\cite{CONTROL} is used. In the same time
    7070the shifters and the GRB-MAGIC group is contacted in different ways described in the next sessions.
    7171
    7272\subsection{The interface to the Central Control}
    7373
    74 An interface of {\it gspot} sends all the relevant informations about it's status to {\it arehucas}.
     74An interface to {\it gspot} sends all the relevant information to {\it arehucas}.
    7575In the case of {\bf NO Alarm State} the standard packages, containing the main global status
    7676of the two subsystems, are continuosly excanged between CC and {\it gspot}.
    7777In the alert case {\it gspot} starts to send to CC special alert packages,
    78 containg major informations of the GRB and on the ''colour'' of the alert.
     78containg information about of the GRB and the ''colour'' of the alert.
    7979The exchange of the alert packages continues untill the following steps occur:
    8080
    8181\begin{itemize}
    82 \item {\it gspot} get from {\it arehucas} the confirmation
    83 that it recived the alert notice; {\it arehucas} must send the alert back in order to
     82\item {\it gspot} receives from {\it arehucas} the confirmation
     83that it has received the alert notice; {\it arehucas} must send the alert back in order
    8484to perform a crosscheck of the relevant data;
    8585\item the alarm state expire after {\bf 5 hours}.
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