Cepheid Period-Luminosity Relation from the AKARI Observations

TL;DR

This study derives the period-luminosity relation for LMC Cepheids using mid-infrared AKARI observations, providing a new calibration in the N3 band with improved dispersion through random-phase corrections.

Contribution

The paper presents the first P-L relation for LMC Cepheids in the N3 band from AKARI data, including random-phase correction methodology.

Findings

Derived N3 band P-L relation: N3 = -3.246 log(P) + 15.844

Dispersion of the P-L relation is 0.149

Random-phase correction improves dispersion by ~7%

Abstract

In this paper, we derive the period-luminosity (P-L) relation for Large Magellanic Cloud (LMC) Cepheids based on mid-infrared AKARI observations. AKARI's IRC sources were matched to the OGLE-III LMC Cepheid catalog. Together with the available I band light curves from the OGLE-III catalog, potential false matches were removed from the sample. This procedure excluded most of the sources in the S7 and S11 bands: hence only the P-L relation in the N3 band was derived in this paper. Random-phase corrections were included in deriving the P-L relation for the single epoch AKARI data, even though the derived P-L relation is consistent with the P-L relation without random-phase correction, though there is a \sim 7 per-cent improvement in the dispersion of the P-L relation. The final adopted N3 band P-L relation is N3 = -3.246 log(P) + 15.844, with a dispersion of 0.149.