New period-luminosity and period-color relations of classical Cepheids

IV. The low-metallicity galaxies IC 1613, WLM, Pegasus, Sextans A and B, and Leo A in comparison to SMC

¹ Department of Physics and Astronomy, Univ. of Basel Klingelbergstrasse 82, 4056 Basel, Switzerland
e-mail: g-a.tammann@unibas.ch
² The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA

Received: 21 December 2010
Accepted: 19 April 2011

Abstract

The metal-poor, fundamental-mode (P0) and first-overtone (P1) Cepheids in the dwarf galaxies IC 1613, WLM, Pegasus, Sextans A, Sextans B, and Leo A are compared with the about equally metal-poor Cepheids of the Small Magellanic Cloud (SMC). The period-color (P-C) and period-luminosity (P-L) relations of the seven galaxies are indistinguishable, but differ distinctly from those in the Large Magellanic Cloud (LMC) and the solar neighborhood. Adopting from independent evidence, one can determine reliable distance moduli for the other dwarf galaxies of (m − M)⁰ = 24.34 ± 0.03, 24.95 ± 0.03, 24.87 ± 0.06, 25.60 ± 0.03 (mean for Sextans A & B), and 24.59 ± 0.03, respectively.