The 'remarkable' M31 globular cluster 037-B327 revisited

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 upsilon(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.