The survey of planetary nebulae in Andromeda (M 31)

The Andromeda (M31) galaxy displays several substructures in its inner halo whose origin as remnants of accreted satellites or perturbations the pre-existing disc are encoded properties their stellar populations (SPs), leaving traces on deep [OIII] 5007 \AA planetary nebulae luminosity functions (PNLFs). By characterizing morphology PNLFs, we constrain origin. From our 54 sq. deg. narrow-band survey M31, identify (PNe) M31 and six major inner-halo - Giant Stream, North East Shelf, G1-Clump, Northern Clump, Western Shelf Stream-D. We measure PNLF parameters from cumulative fits statistically compare PNLFs each substructure disc. link those for Large Magellanic Cloud to published metallicities age measurements parent SPs. absolute magnitudes bright cut-off ($M^{*}$) these sub-populations span a significant magnitude range, despite having similar distance line-of-sight extinction. $M^{*}$ W-shelf Stream-D fainter than predicted by PN evolution models metallicity faint-end slope increases linearly with decreasing fraction mass younger 5 Gyr across regions LMC. Stream NE-shelf consistent being debris an infalling satellite, while G1 Clump appears be linked pre-merger SPs simulations single massive merger event that took place 2--3 ago M31. has unrelated, distinct, Furthermore, this study provides independent evidence is preferentially populated PNe evolved older stars.