Observations of eight globular clusters at 2.3 and 4.7 µm

Abstract

THE Cerro Tololo infrared photometer1 has been used to search several globular clusters for infrared emission between 2.3 and 20 µm, principally to seek evidence for the presence of dust. Recently, more extensive observations using improved short wavelength instrumentation have been obtained at 2.3 and 4.7 µm. The latter observations were concentrated on two groups of predominantly southern clusters: (1) two globular clusters (NGC 6388 and 6441) rich in metals and suggested2 to be of particular interest for the detection of gas thought to be lost from stars during the normal course of stellar evolution; and (2) six clusters with short core relaxation times and large central densities discussed3 in connection with the possible presence of massive central black holes in clusters associated with X-ray sources.