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The TRGB-SBF Project. IV. A Color Calibration of the TRGB in the JWST F090W+F150W Filters

Maksim I. Chazov, Dmitry I. Makarov, R. Brent Tully, Gagandeep S. Anand, Lidia N. Makarova, Yotam Cohen, John P. Blakeslee, Michele Cantiello, Joseph B. Jensen, Gabriella Raimondo

Abstract

Observations with JWST in the F090W band provide a powerful tool for determining galaxy distances based on tip of the red giant branch (TRGB) measurements. It is a great convenience that the TRGB lies at an almost constant absolute magnitude level at low metallicities. However, the TRGB becomes fainter at high metallicities in the F090W filter. Details of this break in slope are critical for precision applications in the acquisition of distances. With an absolute scaling set by the maser distance to NGC 4258 (but excluding the uncertainty in that distance), the value $M^\mathrm{TRGB}_\mathrm{F090W} = -4.40 \pm 0.03$ mag (traditional Vega) is found for $(\mathrm{F090W}-\mathrm{F150W})_0<1.65$ mag. The theoretical RGB isochrone that reaches the color 1.65 at the RGB tip corresponds to metallicity $[M/H] = -0.57$ for a 10 Gyr population. The calibration is used to derive distances for 16 galaxies relative to the megamaser host NGC 4258. Revised distances are on average slightly closer than literature values derived from the same data.

The TRGB-SBF Project. IV. A Color Calibration of the TRGB in the JWST F090W+F150W Filters

Abstract

Observations with JWST in the F090W band provide a powerful tool for determining galaxy distances based on tip of the red giant branch (TRGB) measurements. It is a great convenience that the TRGB lies at an almost constant absolute magnitude level at low metallicities. However, the TRGB becomes fainter at high metallicities in the F090W filter. Details of this break in slope are critical for precision applications in the acquisition of distances. With an absolute scaling set by the maser distance to NGC 4258 (but excluding the uncertainty in that distance), the value mag (traditional Vega) is found for mag. The theoretical RGB isochrone that reaches the color 1.65 at the RGB tip corresponds to metallicity for a 10 Gyr population. The calibration is used to derive distances for 16 galaxies relative to the megamaser host NGC 4258. Revised distances are on average slightly closer than literature values derived from the same data.
Paper Structure (16 sections, 6 equations, 14 figures, 2 tables)

This paper contains 16 sections, 6 equations, 14 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Observed and Theoretical TRGB Color Dependency at F090W
  3. F090W Observations Extending to High Metallicities
  4. Metallicity Effects Along the RGB
  5. Stellar Photometry and TRGB Framework
  6. Photometry
  7. Spatial Selections
  8. Maximum Likelihood Estimation (MLE)
  9. Segmentation of the RGB
  10. Thick vs Thin Slices
  11. TRGB Color relation
  12. Distance measurements
  13. Discussion
  14. Conclusion
  15. Segmentation of the RGB
  16. ...and 1 more sections

Figures (14)

  • Figure 1: CMD of M 87 with the PARSEC isochrones overplotted. The isochrones were shifted to $D=16.3$ Mpc 2025ApJ...982...26A and Galactic extinction reproduced from 2011ApJ...737..103S. Figure extracted from 2025ApJ...982...26A.
  • Figure 2: Teramo SPoT model TRGB magnitudes as a function of metallicity for selected JWST and HST filters. Horizontal black line illustrates the F090W calibration from 2024ApJ...966...89A with one-sigma uncertainties shown with dotted lines.
  • Figure 3: Top panel: CMD of globular clusters observed with Gaia (Fig. 3 in 2018AA...616A..10G). Colors from blue to red distinguish increasing metallicities.; Bottom panel: theoretical RGB isochrones from padova2012MNRAS.427..127B for $t=10$ Gyr and $[M/H]= -2.5$ to 0.5. The isochrone for $[M/H]= -0.57$ (TRGB color at $(\mathrm{F090W}-\mathrm{F150W})_0 = 1.65$) is shown by the black line.
  • Figure 4: NGC 4258: TRGB color relation comparison for stellar populations outside 25 mag arcsec$^{-2}$ isophote and inside this isophote to a radius 0.6 times the radius at 25 mag arcsec$^{-2}$.
  • Figure 5: Segmentation of an RGB CMD into color strips bounding individual maximum likelihood tests. Representative magenta lines are shown. Details discussed in Appendix \ref{['app:RGBsegmentation']}.
  • ...and 9 more figures