The Araucaria Project: The distance to the Small Magellanic Cloud from near infrared photometry of Type~II Cepheids

Ciechanowska A., Pietrzynski G., Szewczyk O., Gieren W., Soszynski I

Published 2010-07-23Version 1

We have obtained deep near infrared J- and K-band observations of 14 BL Herculis and 5 W Virginis SMC stars from the OGLE III survey with the ESO New Technology Telescope equipped with the SOFI infrared camera. From these observations, period-luminosity (P-L) relations in the J and Ks 2MASS bands were derived. The slopes of the K and J band relations of -2.15 +- 0.19 and -1.95 +- 0.24, respectively, agree very well with the corresponding slopes derived previously for population II Cepheids in globular clusters, Galactic bulge and in the Large Magellanic Cloud. The distance modulus to the SMC obtained from our data using P-L relation derived for globular cluster Cepheids equals 18.85 +- 0.07 (statistical) +- 0.07 (systematic without including potential metallicity effect), which within the uncertainties agrees well with the results obtained with other methods.