[an error occurred while processing this directive] EXIST: Science > Context for development of EXIST
 

Context for development of EXIST

Need for Deep Hard X-ray Survey:

  • HX band (~10-600 keV) is last band without imaging all sky survey
  • Only HX survey from HEAO-A4 (1979) with sensitivity ~1/20 flux of brightest source (Crab)
  • Soft X-ray (0.2-2keV) ROSAT survey (1990) with sensitivity ~0.0005 Crab flux
  • Medium X-ray (2-10keV) ABRIXAS2 survey likely (German mission; c. 2002) to match ROSAT sensitivity
  • Pointed HX missions (SIGMA/GRANAT; OSSE/CGRO; HEXTE/RXTE; PDS/BeppoSAX) reveal bright sources: AGN, galactic black holes and transients
  • All sky HX monitor and crude imaging (BATSE/CGRO) show variable HX sky
  • ASCA and BeppoSAX (1999) reveal large obscured AGN population
  • BeppoSAX enables discovery that GRBs are at significant redshift