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arXiv · 1507.03185

Period-Luminosity Relations Derived From the OGLE-III Fundamental Mode Cepheids II: The Small Magellanic Cloud Cepheids

Chow-Choong Ngeow·Shashi M. Kanbur·Anupam Bhardwaj·Harinder P. Singh
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Abstract

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 {\it Spitzer} IRAC bands, respectively. All photometry was corrected for extinction by adopting the Zaritsky's extinction map. Cepheids with periods smaller than $\sim2.5$ 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 $8.0\mu\mathrm{m}$-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 $\Delta \mu=0.483\pm0.015$ mag. This amounts to a difference in distance modulus between the LMC and SMC.

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Chow-Choong Ngeow, Shashi M. Kanbur, Anupam Bhardwaj, Harinder P. Singh. 2015-07-12. Period-Luminosity Relations Derived From the OGLE-III Fundamental Mode Cepheids II: The Small Magellanic Cloud Cepheids. https://doi.org/10.1088/0004-637x/808/1/67

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