Panchromatic Hubble Andromeda Treasury. XIV. The Period-Age Relationship
  of Cepheid Variables in M31 Star Clusters
  We present a sample of 11 M31 Cepheids in stellar clusters, derived from the
overlap of the Panchromatic Hubble Andromeda Treasury (PHAT) cluster catalog
and the Pan-STARRS1 (PS1) disk Cepheid catalog. After identifying the PS1
Cepheids in the HST catalog, we calibrate the PS1 mean magnitudes using the
higher resolution HST photometry, revealing up to 1 magnitude offsets due to
crowding effects in the ground-based catalog. We measure ages of the clusters
by performing single stellar population fits to their color-magnitude diagrams
(CMDs) excluding their Cepheids. From these cluster age measurements, we derive
an empirical period-age relation which agrees well with the existing literature
values. By confirming this relation for M31 Cepheids, we justify its
application in high-precision pointwise age estimation across M31.
