Period-luminosity relations for Galactic Cepheid variables with independent distance measurements

Abstract

In this paper, we derive the period-luminosity (PL) relation for Galactic Cepheids with recent independent distance measurements from open cluster, Barnes-Evans surface brightness, interferometry and HST astrometry techniques. Our PL relation confirms the results of Tammann et al. (2003), which showed that the Galactic Cepheids follow a different PL relation to their LMC counterparts. Our results also show that the slope of the Galactic PL relation is inconsistent with the LMC slope with more than 95% confidence level. We apply this Galactic PL relation to find the distance to NGC 4258. Our result of mu_o=29.49\pm0.06(random error)mag. agrees at the ~1.4sigma level with the geometrical distance of μ_{geo}=29.28\pm0.15mag. from water maser measurements..

7 pages, 4 tables, 1 figure. MNRAS in-press, correct typesetting error in Table 3