The M33 Synoptic Stellar Survey. III. Miras and LPVs in griJHKs

TL;DR

This study uses multiband observations and machine learning to identify and analyze Miras and LPVs in galaxy M33, discovering thousands of new variables and establishing a new distance measurement.

Contribution

It introduces a novel approach combining multiband data and machine learning to identify and characterize Miras and LPVs in M33, including the first detection of a first-overtone pulsation sequence.

Findings

Recovered ~1,300 known Miras

Identified ~13,000 new Miras and LPVs

Derived a precise distance modulus of 24.629 mag

Abstract

We present the results of a search for Miras and long-period variables (LPVs) in M33 using griJHKs archival observations from the Canada-France-Hawai'i Telescope. We use multiband information and machine learning techniques to identify and characterize these variables. We recover ~1,300 previously-discovered Mira candidates and identify ~13,000 new Miras and LPVs. We detect for the first time a clear first-overtone pulsation sequence among Mira candidates in this galaxy. We use O-rich, fundamental-mode Miras in the LMC and M33 to derive a distance modulus for the latter of 24.629 +/- 0.046 mag.