A Distance Measurement to M33 Using Optical Photometry of Mira Variables

Abstract

We present a systematic analysis to determine and improve the pulsation periods of 1637 known long-period Mira variables in M33 using gri-band light curves spanning ∼18 yr from several surveys, including the M33 variability survey, Panoramic Survey Telescope and Rapid Response System, Palomar Transient Factory (PTF), intermediate PTF, and Zwicky Transient Facility. Based on these collections of light curves, we found that optical-band light curves that are as complete as possible are crucial to determine the periods of distant Miras. We demonstrated that the machine-learning techniques can be used to classify Miras into O-rich and C-rich based on the (J − K s ) period–color plane. Finally, We derived the distance modulus to M33 using O-rich Miras at maximum light together with our improved periods as 24.67 ± 0.06 mag, which is in good agreement with the recommended value given in the literature.

A 1.3% Distance to M33 from Hubble Space Telescope Cepheid Photometry

“…We also find good agreement with the RR Lyrae distance by Sarajedini et al (2006). Finally, the two Mira-based distances (Yuan et al 2018;Ou et al 2023) differ by 0.13 mag, which can be attributed to the use of different data sets and methodologies and differences in periods and possible calibration systematics between ground-and space-based data.…”

Zwicky Transient Facility and Globular Clusters: The gr-band Period–Luminosity Relations for Mira Variables at Maximum Light and their Applications to Local Galaxies

“…Our work would be similar to the work of Menzies & Whitelock (1985) and Feast et al (2002), but using the most up-to-date and homogeneous globular cluster distances as given in Baumgardt & Vasiliev (2021). We choose to derive the PL relations at maximum light because their dispersions were found to be smaller than the mean-light counterparts (Kanbur et al 1997;Bhardwaj et al 2019;Ou & Ngeow 2022;Ou et al 2023). Though not an optimal choice, the derived optical band PL relations will still be valuable in the era of LSST, because the six filters set employed by LSST (ugrizy) do not extend to the NIR.…”

“…Miras. Using the determined periods P n and JK-band photometry, adopted either fromSloan et al (2010) or the Two Micron All Sky Survey(Skrutskie et al 2006), we classified the 14 globular clusters Miras as O-rich Miras based on the K-nearest neighbor (KNN) algorithm (as done inOu et al 2023). Furthermore, for samples of Miras that extended to ∼1000 days the PL relations were often fitted with either a segmented or a quadratic relation (for examples, seeIta & Matsunaga 2011; …”