A Search for the Cooling Flow Accretion Population: Optical and Near-Infrared Imaging of NGC 1275

摘要

We present near-infrared and optical images of NGC 1275, the cD galaxy at the center of the Perseus cluster, and a well-known cooling flow. Although cooling flows are common (perhaps occurring in >50/100 of X-ray clusters) and the mass accreted over the lifetime of the cluster 10~12 M◎, attempts to detect the cooled gas at wavelengths other than X-rays has met with limited success. In this paper, we measure the optical and near-infrared brightness profiles of NGC 1275, in an attempt to detect spatially extended low-mass stars that may have formed from the cooled gas. To measure the profiles to the required low flux levels, they have been corrected for overlapping galaxy halos and scattered light. We find that our profiles are inconsistent with models of low-mass star formation unless the initial mass function has an upper mass cutoff less than 0.1 M◎, or the mass of gas accumulated over the lifetime of the cluster is 1/10010/100 of that predicted from the X-ray mass accretion rate determined at the present epoch.