2DARK天文志

Abstract: Long Gamma Ray Bursts (GRBs) constitute an important tool to study the
Universe near and beyond the epoch of reionization. We delineate here the
characteristics of an 'ideal' instrument for the search of GRBs at z>6-10. We
find that the detection of these objects requires soft band detectors with a
high sensitivity and moderately large FOV. In the light of these results, we
compare available and planned GRB missions, deriving conservative predictions
on the number of high-z GRBs detectable by these instruments along with the
maximum accessible redshift. We show that the Swift satellite will be able to
detect various GRBs at z>6, and likely at z>10 if the trigger threshold is
decreased by a factor of ~2. Furthermore, we find that INTEGRAL and GLAST are
not the best tool to detect bursts at z>6: the former being limited by the
small FOV, and the latter by its hard energy band and relatively low
sensitivity. Finally, future missions (SVOM, EDGE, but in particular EXIST)
will provide a good sample of GRBs at z>6 in a few years of operation.