Astrophysical Distance Scale. IV. Preliminary Zero-point Calibration of the JAGB Method in the HST/WFC3-IR Broad J-band (F110W) Filter

Abstract

Abstract We present an absolute calibration of the J-region Asymptotic Giant Branch (JAGB) method using published photometry of resolved stars in 20 nearby galaxies observed with the Hubble Space Telescope using the WFC3-IR camera and the F110W (broad J-band) filter. True distance moduli for each of the galaxies are based on the Tip of the Red Giant Branch (TRGB) method as uniformly determined by Dalcanton et al. From a composite color–magnitude diagram composed of over 6 million stars, leading to a sample of 453 JAGB stars in these galaxies, we find M F 110 W JAGB = − 5.77 ± 0.02 mag (statistical error on the mean). The external scatter seen in a comparison of the individual TRGB and the JAGB moduli is ±0.081 mag (or 4% in distance). Some of this scatter can be attributed to small number statistics arising from the sparse JAGB populations found in the generally low-luminosity galaxies that comprise the particular sample studied here. However, if this intermethod scatter is shared equitably between the JAGB and TRGB methods, that implies that each is good to ±0.06 mag, or better than 3% in distance.