Globular clusters in the outer halo of M31: The survey

We report the discovery of 40 new globular clusters (GCs) that have been found in surveys of the halo of M31 based on the Isaac Newton Telescope/Wide-Field Camera and Canada–France–Hawaii Telescope/Megacam imagery. A subset of these new GCs are of an extended, diffuse nature and include those already found in Huxor et al. The search strategy is described and basic positional and V and I photometric data are presented for each cluster. For a subset of these clusters, K-band photometry is also given. The new clusters continue to be found to the limit of the survey area (∼100 kpc), revealing that the GC system of M31 is much more extended than previously realized. The new clusters increase the total number of confirmed GCs in M31 by approximately 10 per cent and the number of confirmed GCs beyond 1° (≈14 kpc) by more than 75 per cent. We have also used the survey imagery as well recent Hubble Space Telescope archival data to update the Revised Bologna Catalogue of M31 globular clusters.