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). The overall program aims to calibrate three independent
methods: (1) Tip of the Red Giant Branch (TRGB) stars, (2) JAGB (J-Region
Asymptotic Giant Branch) stars, and (3) Cepheids. To date, our program includes
10 nearby galaxies, hosting 11 Type Ia supernovae (SNe Ia) suitable for
measuring the Hubble constant ($H_0$). It also includes the galaxy NGC 4258,
whose geometric distance provides the zero-point calibration. In this paper we
discuss our results from the TRGB and JAGB methods. Our current best (highest
precision) estimate is $H_0$ = 70.39 $pm$ 1.22 (stat) $pm$ 1.33 (sys) $pm$
0.70 ($sigma_{SN})$, based on the TRGB method alone, with a total of 24 SN Ia
calibrators from both HST and JWST data. Based on our new JWST data only, and
tying into SNe Ia, we find values of $H_0$ = 68.81 $pm$ 1.79 (stat) $pm$ 1.32
(sys) for the TRGB, and $H_0$ = 67.80 $pm$ 2.17 (stat) $pm$ 1.64 (sys)
km/s/Mpc for the JAGB method. The distances measured using the TRGB and the
JAGB method agree, on average, at a level better than 1%, and with the SH0ES
Cepheid distances at just over the 1% level. Our results 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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