Zwicky Transient Facility and Globular Clusters: The Period-Luminosity and Period-Wesenheit Relations for Anomalous Cepheids Supplemented with Large Magellanic Cloud Sample

TL;DR

This paper establishes new gri-band period-luminosity and period-Wesenheit relations for anomalous Cepheids, aiding distance measurements to dwarf galaxies, based on combined data from globular clusters and the Large Magellanic Cloud.

Contribution

It provides the first gri-band PL and PW relations for fundamental mode anomalous Cepheids, calibrated with high-accuracy distances from globular clusters and the LMC.

Findings

g-band PL relation similar to B-band PL relation

Applied relations to Crater II, estimating a larger distance modulus

Calibrations useful for distance measurements despite small sample size

Abstract

We present the first gri-band period-luminosity (PL) and period-Wesenheit (PW) relations for the fundamental mode anomalous Cepheids. These PL and PW relations were derived from a combined sample of five anomalous Cepheids in globular cluster M92 and the Large Magellanic Cloud, both of which have distance accurate to ~1% available from literature. Our g-band PL relation is similar to the B-band PL relation as reported in previous study. We applied our PL and PW relations to anomalous Cepheids discovered in dwarf galaxy Crater II, and found a larger but consistent distance modulus than the recent measurements based on RR Lyrae. Our calibrations of gri-band PL and PW relations, even though less precise due to small number of anomalous Cepheids, will be useful for distance measurements to dwarf galaxies.