Coordinated JWST Imaging of Three Distance Indicators in a SN Host Galaxy and an Estimate of the TRGB Color Dependence

TL;DR

This study demonstrates JWST's capability to precisely measure distances using multiple stellar indicators in a galaxy, confirming the TRGB as a reliable standard candle in infrared wavelengths for improved Hubble constant estimates.

Contribution

First successful detection and measurement of three stellar distance indicators with JWST in a SN host galaxy, including a preliminary calibration of the TRGB's IR color dependence.

Findings

JWST can measure distances with ~0.05 mag precision using multiple indicators.

The TRGB slope in IR is consistent with previous measurements and models.

Empirical evidence supports using the TRGB as a standard candle in IR wavelengths.

Abstract

Boasting a 6.5m mirror in space, JWST can increase by several times the number of supernovae (SNe) to which a redshift-independent distance has been measured with a precision distance indicator (e.g., TRGB or Cepheids); the limited number of such SN calibrators currently dominates the uncertainty budget in distance ladder Hubble constant (H0) experiments. JWST/NIRCAM imaging of the Virgo Cluster galaxy NGC4536 is used here to preview JWST program GO-1995, which aims to measure H0 using three stellar distance indicators (Cepheids, TRGB, JAGB/carbon stars). Each population of distance indicator was here successfully detected -- with sufficiently large number statistics, well-measured fluxes, and characteristic distributions consistent with ingoing expectations -- so as to confirm that we can acquire distances from each method precise to about 0.05mag (statistical uncertainty only). We leverage overlapping HST imaging to identify TRGB stars, cross-match them with the JWST photometry, and present a preliminary constraint on the slope of the TRGB's F115W-(F115W}-F444W) relation equal to -0.99 +/- 0.16 mag/mag. This slope is consistent with prior slope measurements in the similar 2MASS J-band, as well as with predictions from the BASTI isochrone suite. We use the new TRGB slope estimate to flatten the two-dimensional TRGB feature and measure a (blinded) TRGB distance relative to a set of fiducial TRGB colors, intended to represent the absolute fiducial calibrations expected from geometric anchors such as NGC4258 and the Magellanic Clouds. In doing so, we empirically demonstrate that the TRGB can be used as a standardizable candle at the IR wavelengths accessible with JWST.