Stellar Populations Beyond the Local Group with the NGST

Abstract

We present simulated J- and K-band observations of stars in the Virgo and Coma clusters of galaxies using the proposed Next Generation Space Telescope with a Near-Infrared Camera, and discuss some of the science results that might be obtained. The proposed telescope will be able to resolve the brightest ~3 magnitudes of the red giant branch in the halos of galaxies in the Virgo Cluster and may be able to resolve stars at the tip of the red giant branch in the Coma Cluster. The simulations show that the background light is more important than the size of the aperture in determining the limiting magnitude of the observations. Therefore, we recomment that the Next Generation Space Telescope be placed in a 1 x 3 a.u. orbit to minimize background light.