JWST Photometry of Globular Clusters in A2744. II. Luminosity and Color Distributions

Abstract

Deep JWST imaging of the giant galaxy cluster A2744, at redshift z = 0.308, is used to explore the features of its rich population of globular clusters (GCs), building on our initial survey of the system. We use the photometry of more than 10,000 GCs over a 3 mag range to construct the GC luminosity function and color distribution. These results now specifically account for photometric incompleteness as a function of location relative to the five giant galaxies that dominate the gravitational potential of A2744. The total GC population in A2744 is estimated at N GC ≥ 1.1 × 105, consistent with its high total mass. We also directly compare the observed distributions with theoretical predictions for GC populations drawn from the recent EMP-Pathfinder simulations, viewed at the same 3.5 Gyr look-back time as the cluster. The simulations match the observations well, with the only notable disagreement being that the simulations predict larger numbers of GCs at high metallicity formed after z ≃ 2 than are seen in the data.