Kavli Affiliate: Wendy L. Freedman
| First 5 Authors: Wendy L. Freedman, Barry F. Madore, In Sung Jang, Taylor J. Hoyt, Abigail J. Lee
| Summary:
We present the latest results from the Chicago Carnegie Hubble Program (CCHP)
to measure the Hubble constant using data from the James Webb Space Telescope
(JWST). This program is based upon three independent methods: (1) Tip of the
Red Giant Branch (TRGB) stars, (2) JAGB (J-Region Asymptotic Giant Branch)
stars, and (3) Cepheids. Our program includes 10 nearby galaxies, each hosting
Type Ia supernovae, suitable for measuring the Hubble constant (Ho). It also
includes NGC 4258, which has a geometric distance, setting the zero point for
all three methods. The JWST observations have significantly higher
signal-to-noise and finer angular resolution than previous observations with
the Hubble Space Telescope (HST). We find three independent values of Ho =
69.85 +/- 1.75 (stat) +/- 1.54 (sys) for the TRGB, Ho = 67.96 +/- 1.85 (stat)
+/- 1.90 (sys) for the JAGB, and Ho = 72.05 +/- 1.86 (stat) +/- 3.10 (sys)
km/s/Mpc for Cepheids. Tying into supernovae, and combining these methods
adopting a flat prior, yields our current estimate of Ho = 69.96 +/- 1.05
(stat) +/- 1.12 (sys) km/s/Mpc. The distances measured using the TRGB and the
JAGB method agree at the 1% level, but differ from the Cepheid distances at the
2.5-4% level. The value of Ho based on these two methods with JWST data alone
is Ho = 69.03 +/- 1.75 (total error) km/sec/Mpc. These numbers are consistent
with the current standard Lambda CDM model, without the need for the inclusion
of additional new physics. Future JWST data will be required to increase the
precision and accuracy of the local distance scale.
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