The MAVERIC Survey: Still No Evidence for Accreting Intermediate-mass Black Holes in Globular Clusters

Abstract

We present the results of an ultradeep, comprehensive radio continuum survey for the accretion signatures of intermediate-mass black holes (IMBHs) in globular clusters (GCs). The sample, imaged with the Karl G. Jansky Very Large Array and the Australia Telescope Compact Array, comprises 50 Galactic GCs. No compelling evidence for an IMBH is found in any cluster in our sample. In order to achieve the highest sensitivity to low-level emission, we also present the results of an overall stack of our sample as well as various subsamples, also finding nondetections. These results strengthen the idea that IMBHs with masses ≳1000 M ⊙ are rare or absent in GCs.