X-RED: a satellite mission concept to detect early universe gamma ray bursts
Krumpe, Mirko; Coffey, Deirdre; Egger, Georg; Vilardell, Francesc; Lefever, Karolien; Liermann, Adriane1; Hoffmann, Agnes I.; Steiper, Joerg; Cherix, Marc; Albrecht, Simon; Russo, Pedro; Strodl, Thomas; Wahlin, Rurik; Deroo, Pieter; Parmar, Arvind; Lund, Niels; Hasinger
Gamma ray bursts (GRBs) are the most energetic eruptions known in the Universe.
Instruments such as Compton-GRO/BATSE and the GRB monitor on BeppoSAX have detected
more than 2700 GRBs and, although observational confirmation is still required, it is
now generally accepted that many of these bursts are associated with the collapse of
rapidly spinning massive stars to form black holes. Consequently, since first generation
stars are expected to be very massive, GRBs are likely to have occurred in significant
numbers at early epochs. X-red is a space mission concept designed to detect these
extremely high redshifted GRBs, in order to probe the nature of the first generation of
stars and hence the time of reionisation of the early Universe. We demonstrate that the
gamma and x-ray luminosities of typical GRBs render them detectable up to extremely high
redshifts (z ~ 10to30), but that current missions such as HETES and SWIFT operate outside
the observational range for detection of high redshift GRB afterglows. Therefore, to
redress this, we present a complete mission design from teh science case to the mission
architecture and payload, the latter comprising three instruments, namely wide field x-ray
cameras to detect high redshift gamma-rays, an x-ray focussing telescope to determine
accurate coordinates and extract spectra, and an infrared spectrograph to observe the high
redshift optical afterglow. The mission is expected to detect and identify for the first
time GRBs with z ? 10, thereby providing constraints on properties of the first generation
of stars and the history of the early Universe.