An Empirical Calibration of the Tip of the Red Giant Branch Distance Method in the Near Infrared. II. JWST NIRCam Wide Filters

Understand

The tip of the red giant (TRGB) is a standardizable candle and is identifiable as the discontinuity at the bright extreme of the red giant branch (RGB) stars in color-magnitude diagram (CMD) space.

• The TRGB-based distance method has been calibrated and used to measured distances to galaxies out to $D\leq20$ Mpc with the $I$-band equivalent Hubble Space Telescope ($HST$) $F814W$ filter, and as an important rung in the distance ladder to measure the Hubble constant, $H_0$.
• In the infrared (IR), the TRGB apparent magnitude ranges from $1-2$ magnitudes brighter than in the optical, and now with the IR James Webb Space Telescope ($JWST$) observatory the feasible distance range of the TRGB method can be extended to $\sim50$ Mpc.
• However, in the IR the TRGB luminosity depends to varying degrees on stellar metallicity and age.