Envisioning the Distance Ladder in the Era of the Habitable Worlds Observatory

Fuente: arXiv
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Main Authors: Anand, Gagandeep, Durbin, Meredith, Beaton, Rachael, Jensen, Joseph, Riess, Adam
Format: Preprint
Published: 2025
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author Anand, Gagandeep
Durbin, Meredith
Beaton, Rachael
Jensen, Joseph
Riess, Adam
author_facet Anand, Gagandeep
Durbin, Meredith
Beaton, Rachael
Jensen, Joseph
Riess, Adam
contents The current state-of-the-art cosmic distance ladder requires three rungs--geometric distances, primary indicators, and Type Ia Supernovae--to achieve a 1% measurement of the Hubble constant $H_0$. The Habitable Worlds Observatory will have the sensitivity and resolution to reduce this to a two-step measurement, eliminating the third rung entirely and reaching into the Hubble flow with stellar distance indicators such as Cepheid variables and the tip of the red giant branch alone. We discuss the requirements for a program to measure $H_0$ to 1% with HWO here, including telescope and instrument design considerations. We also comment on the potential of HWO to measure distances to low-mass dwarf galaxies via their RR Lyrae stars.
format Preprint
id arxiv_https___arxiv_org_abs_2507_02056
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Envisioning the Distance Ladder in the Era of the Habitable Worlds Observatory
Anand, Gagandeep
Durbin, Meredith
Beaton, Rachael
Jensen, Joseph
Riess, Adam
Cosmology and Nongalactic Astrophysics
Instrumentation and Methods for Astrophysics
The current state-of-the-art cosmic distance ladder requires three rungs--geometric distances, primary indicators, and Type Ia Supernovae--to achieve a 1% measurement of the Hubble constant $H_0$. The Habitable Worlds Observatory will have the sensitivity and resolution to reduce this to a two-step measurement, eliminating the third rung entirely and reaching into the Hubble flow with stellar distance indicators such as Cepheid variables and the tip of the red giant branch alone. We discuss the requirements for a program to measure $H_0$ to 1% with HWO here, including telescope and instrument design considerations. We also comment on the potential of HWO to measure distances to low-mass dwarf galaxies via their RR Lyrae stars.
title Envisioning the Distance Ladder in the Era of the Habitable Worlds Observatory
topic Cosmology and Nongalactic Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2507.02056