2002MNRAS.329..461B

The M31 globular cluster candidate 037-B327 has long been known to be an extremely red, non-stellar object. The first published spectrum of this object is used to confirm that it is a globular cluster belonging to M31, with rather typical values of v_r=-338±12 km s^-1 and [Fe/H]=-1.07±0.20 dex. Using the spectroscopic metallicity to predict the intrinsic colours, we derive a reddening value of E(B-V)=1.30±0.04, in good agreement with the value obtained using reddening-free parameters. The extinction-corrected magnitude of 037-B327 is V_0=12.73 (absolute magnitude M_V=-11.74), which makes it the most luminous globular cluster in M31. We examine van den Bergh's argument regarding the brightest and most-reddened globular cluster in M31; we find that the brightest clusters are more heavily reddened than average, but this can be explained by selection effects rather than a different R_V in M31.