Predicted properties of Galactic and Magellanic Classical Cepheids in the SDSS filters

TL;DR

This paper provides a comprehensive theoretical analysis of Galactic and Magellanic Cepheids in SDSS filters, detailing their properties and relations across different metallicities and pulsation modes.

Contribution

It introduces the first extensive theoretical models for Cepheid properties in SDSS filters, including updated atmospheres and detailed relations across metallicities.

Findings

Fundamental PL relations deviate from linearity at short periods.

Slopes are mildly steeper than previous empirical relations.

Discrepancies range from 13% in u-band to 3% in z-band.

Abstract

We present the first extensive and detailed theoretical scenario for the interpretation of Cepheid properties observed in the SDSS filters. Three sets of nonlinear convective pulsation models, corresponding to the chemical compositions of Cepheids in the Milky Way, the Large Magellanic Cloud and the Small Magellanic Cloud respectively, are transformed into the SDSS bands by relying on updated model atmospheres. The resulting observables, namely the instability strip boundaries and the light curves, as well as the Period-Luminosity, the Wesenheit and the Period-Luminosity-Colour relations, are discussed as a function of the metal content, for both the fundamental and the first overtone mode. The fundamental PL relations are found to deviate from linear relations when computed over the whole observed Cepheid period range, especially at the shorter wavelenghts, confirming previous findings in the Johnson-Cousins bands. The obtained slopes are found to be mildly steeper than the ones of the semiempirical and the empirical relations available in the literature and covering roughly the same period range, with the discrepancy ranging from about 13% in u-band to about 3% in z.