Multi-year BATSE earth occultation monitoring of NGC4151

Because the Earth occultation technique allows BATSE to be used as an all-sky monitor, BATSE is uniquely able to provide continuous observations of NGC4151 over the entire lifetime of the Compton GRO mission. Continuous 2154 day light-curves for the Seyfert galaxy NGC4151 have been derived from Earth occultation analysis of CGRO BATSE data. Light-curves for the 20–70 keV and 70–200 keV bands are shown and found to have an average flux of 11×10−3 photons cm−2 s−1 and 2.3×10−3 photons cm−2 s−1 respectively. Evidence for intrinsic source variability is observed in both 20–70 keV and 70–200 keV bands with a fractional variation ratio measured at Fvar=0.2.