Cepheids in M31: The PAndromeda Cepheid Sample
Lee, Chien-Hsiu; Bender, Ralf; Seitz, Stella; Tonry, J. L.; Metcalfe, N.; Burgett, W. S.; Kaiser, N.; Wainscoat, R. J.; Draper, P. W.; Hodapp, K. W.; Hopp, Ulrich; Riffeser, Arno; Kudritzki, R. -P.; Snigula, Jan; Kodric, Mihael; Goessl, Claus; Koppenhoefer, Johannes; Obermeier, Christian
Germany, United States, United Kingdom
Abstract
We present the largest Cepheid sample in M31 based on the complete Pan-STARRS1 survey of Andromeda (PAndromeda) in the r P1, i P1, and g P1 bands. We find 2686 Cepheids with 1662 fundamental-mode Cepheids, 307 first-overtone Cepheids, 278 type II Cepheids, and 439 Cepheids with undetermined Cepheid type. Using the method developed by Kodric et al., we identify Cepheids by using a three-dimensional parameter space of Fourier parameters of the Cepheid light curves combined with a color cut and other selection criteria. This is an unbiased approach to identify Cepheids and results in a homogeneous Cepheid sample. The period-luminosity relations obtained for our sample have smaller dispersions than in our previous work. We find a broken slope that we previously observed with HST data in Kodric et al., albeit with a lower significance.