2003MNRAS.340..143W

I present preliminary BV resolved stellar photometry of the M31 disc measured from the data set of the NOAO/CTIO Local Group Survey. I have performed detailed analyses of the star-formation histories in and around three currently active regions in the M31 disc: OB 78, OB 102 and the north-east spiral arm. The results suggest that low Hα emission from OB 78 compared with other active regions is directly related to the details of the recent star formation histories of the regions. In addition, while every active region I analysed shows a recent increase in star formation activity, some active regions also contain overdensities of stars with ages ≲100 Myr compared with adjacent regions. The adjacent regions show a relatively constant, low star formation rate over the past 100 Myr. There is no significant difference between the stellar populations on either side of the active regions. This symmetry provides no obvious signature of recent propagation of star formation near these currently active regions of the M31 disc.