Speaker
Description
Type II Cepheids are useful distance indicators and stellar tracers for old stellar populations. For instance, they have been used to find the distances of the Magellanic Clouds and to measure their tridimensional geometry.
Rubin LSST will allow us to detect and characterize Type II Cepheids in the Local Group galaxies and beyond. In particular, we have verified that the Rubin LSST observations will allow us to observe and correctly characterize Type II Cepheids up to a few Mpc. This will enable us to use them as alternative calibrators of the cosmic distance scale. To this aim, we will adopt locally calibrated period-luminosity-metallicity relations which require both photometry and spectroscopically-based abundances. While optical photometry can be provided by Ruvin LSST and the Near Infra-red by space missions like Euclid/Roman, WST with its sensitivity and multiplexing capabilities, will be the only instrument capable of providing the metallicity information. This, in turn, will make type II Cepheids valid alternative standard candles for the extragalactic distance scale.
