The low-mass initial mass function in the Orion nebula cluster based on HST/NICMOS III imaging

We present deep HST/NICMOS Camera 3 F110W and F160W imaging of a 26 � ×33 � , corresponding to 3.1 pc ×3.8 pc, noncontiguous field towards the Orion nebula cluster (ONC). The main aim is to determine the ratio of low-mass stars to brown dwarfs for the cluster as a function of radius out to a radial distance of 1.5 pc. The sensitivity of the data outside the nebulous central region is F160W ≤ 21.0 mag, significantly deeper than previous studies of the region over a comparable area. We