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arXiv · 1509.04791

Panchromatic Hubble Andromeda Treasury. XIV. The Period-Age Relationship of Cepheid Variables in M31 Star Clusters

Peter Senchyna·L. Clifton Johnson·Julianne J. Dalcanton·Lori C. Beerman·Morgan Fouesneau·Andrew Dolphin·Benjamin F. Williams·Philip Rosenfield·Søren S. Larsen
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Abstract

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.

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Peter Senchyna, L. Clifton Johnson, Julianne J. Dalcanton, Lori C. Beerman, Morgan Fouesneau, Andrew Dolphin, Benjamin F. Williams, Philip Rosenfield, Søren S. Larsen. 2015-09-16. Panchromatic Hubble Andromeda Treasury. XIV. The Period-Age Relationship of Cepheid Variables in M31 Star Clusters. https://doi.org/10.1088/0004-637x/813/1/31

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