Development of an Extremely Sensitive Infrared Photometer for the Investigation of 'Dark Matter' in Galactic Halos

by James Walter Bergstrom

Under the supervision of Professor Terry J. Jones


A general purpose IR photometer utilizing a single-element InSb detector, and a selection of filters and apertures was designed and built. The noise sources for the cryogenically cooled transimpedance preamplifier were identified and measured. The instrument included several especially large apertures for an experiment to investigate the so-called "dark matter" thought to exist in halos around spiral galaxies. The IR emission in the halo of edge-on spiral galaxy NGC 4244 was detected at radii exceeding previous measurements. The IR emission at larger galactic radii is consistent with de Vaucouleurs "r^1/4 law", and the mass-to-light ratio at K is in agreement with previous results showing no evidence of a massive halo consisting of "substellar objects".