\section{Timing considerations}

{\ldots \it \bf HAS TO BE UPDATED AND COMPLETED!! \ldots \\}
{\it Here, all possible models should go in with reasonning why certain time 
or flux estimates are proposed.  We have now only estimates on extrapolations 
of the \eg power-laws. Maybe we should include: IC (in many possible combinations), 
hadronic emission models (see~\cite{TASC}), Cannonball model. }
\par

The EGRET~\cite{EGRET} instrument on the CGRO 
has detected GeV emission of GRB940217 promptly and 90 min. after 
the burst onset. 
\\
\par
In~\cite{DERMER}, two peaks in the GeV light curve are calculated. An early maximum coincident 
with the MeV eak is the high-eneryg extension of the synchrotron component, some seconds 
after the burst onset. The second maximum peaking at $\approx$ 1.5 hours is due primarily to 
SSC radiation with significant emission of up to $10^5$ sec. ($\approx 25$ hours) after the burst. 
\\
\par
Li, Dai and Lu~\cite{LI} suggest GeV emission after pion production and some thermalization of the 
UHE component with radiation maxima of up to one day or even one week (accompanied by long-term
neutrino emission).

\par
\ldots \textit{\bf UNTIL WHEN WILL WE OBSERVE THE BURST AFTER OCCURRANCE}   \ldots
\par

\subsection{Determine reasonable upper limit for observation duration }