The Astrophysical Distance Scale. III. Distance to the Local Group Galaxy WLM Using Multiwavelength Observations of the Tip of the Red Giant Branch, Cepheids, and JAGB Stars

The local determination of the Hubble constant sits at a crossroad. Current estimates of the local expansion rate of the universe differ by about 1.7σ, derived from the Cepheid- and TRGB-based calibrations, applied to Type Ia supernovae. To help elucidate possible sources of systematic error causing the tension, we show in this study the recently developed distance indicator, the J-region Asymptotic Giant Branch (JAGB) method, can serve as an independent cross-check and comparison with other local distance indicators. Furthermore, we make the case that the JAGB method has substantial potential as an independent, precise, and accurate calibrator of Type Ia supernovae for the determination of H₀. Using the Local Group galaxy Wolf-Lundmark-Melotte (WLM), we present distance comparisons between the JAGB method, a TRGB measurement at near-infrared (JHK) wavelengths, a TRGB measurement in the optical I band, and a multiwavelength Cepheid period-luminosity relation determination. We find $\begin{eqnarray*}\begin{array}{rcl}{\mu }_{0}\,(\mathrm{JAGB}) & = & 24.97\pm 0.02\ (\mathrm{stat})\pm 0.04\ (\mathrm{sys})\ \mathrm{mag}\\ {\mu }_{0}\,({\mathrm{TRGB}}_{\mathrm{NIR}}) & = & 24.98\pm 0.04\ (\mathrm{stat})\pm 0.07\ (\mathrm{sys})\ \mathrm{mag}\\ {\mu }_{0}\,({\mathrm{TRGB}}_{{\rm{F}}814{\rm{W}}}) & = & 24.93\pm 0.02\ (\mathrm{stat})\pm 0.06\ (\mathrm{sys})\ \mathrm{mag}\\ {\mu }_{0}\,(\mathrm{Cepheids}) & = & 24.98\pm 0.03\ (\mathrm{stat})\pm 0.04\ (\mathrm{sys})\ \mathrm{mag}.\end{array}\end{eqnarray*}$. All four methods are in good agreement, confirming the local self-consistency of the four distance scales at the 3% level and adding confidence that the JAGB method is as accurate and as precise a distance indicator as either of the other three astrophysically based methods.