Kavli Affiliate: Wendy L. Freedman
| First 5 Authors: Barry F. Madore, Wendy L. Freedman, Abigail Lee, ,
| Summary:
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 HST 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. (2012). 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_{F110W}{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 inter-method scatter is shared equitably
between the JAGB and TRGB methods that implies that each are good to +/-0.06
mag, or better than 3% in distance.
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