PERIOD–LUMINOSITY RELATIONS DERIVED FROM THE OGLE-III FUNDAMENTAL MODE CEPHEIDS. II. THE SMALL MAGELLANIC CLOUD CEPHEIDS

In this paper we present multi-band period–luminosity (P–L) relations for fundamental mode Cepheids in the SMC. The optical VI-band mean magnitudes for these SMC Cepheids were taken from the third phase of the Optical Gravitational Lensing Experiment (OGLE-III) catalog. We also matched the OGLE-III SMC Cepheids to 2MASS and SAGE-SMC catalog to derive mean magnitudes in the JHK-bands and the four Spitzer IRAC bands, respectively. All photometry was corrected for extinction by adopting Zaritsky’s extinction map. Cepheids with periods smaller than ∼2.5 days were removed from the sample. In addition to the extinction corrected P–L relations in nine filters from optical to infrared, we also derived the extinction-free Wesenheit function for these Cepheids. We tested the nonlinearity of these SMC P–L relations (except the 8.0 &mgr; m ?> -band P–L relation) at 10 days: none of the P–L relations show statistically significant evidence of nonlinearity. When compared to the P–L relations in the LMC, the t-test results revealed that there is a difference between the SMC/LMC P–L slopes only in the V- and J-band. Further, we found excellent agreement between the SMC/LMC Wesenheit P–L slope. The difference in LMC and SMC Period–Wesenheit relation LMC and SMC zero points was found to be Δ &mgr; = 0.483 ± 0.015 ?> mag. This amounts to a difference in distance modulus between the LMC and SMC.