Distances to PHANGS Galaxies: New Tip of the Red Giant Branch Measurements and Adopted Distances

TL;DR

This paper reports new tip of the red giant branch (TRGB) distance measurements for 11 nearby galaxies using PHANGS-HST data, providing crucial distance estimates for understanding galaxy properties and supporting multiwavelength studies.

Contribution

It presents the first TRGB distance measurements for five galaxies and offers the most accurate distances for eight others, enhancing the PHANGS galaxy dataset.

Findings

TRGB distances for 11 galaxies ranging from 4 to 15 Mpc.

First published TRGB distances for five galaxies.

Compilation of distances for 118 galaxies in the PHANGS sample.

Abstract

PHANGS-HST is an ultraviolet-optical imaging survey of 38 spiral galaxies within ~20 Mpc. Combined with the PHANGS-ALMA, PHANGS-MUSE surveys and other multiwavelength data, the dataset will provide an unprecedented look into the connections between young stars, HII regions, and cold molecular gas in these nearby star-forming galaxies. Accurate distances are needed to transform measured observables into physical parameters (e.g., brightness to luminosity, angular to physical sizes of molecular clouds, star clusters and associations). PHANGS-HST has obtained parallel ACS imaging of the galaxy halos in the F606W and F814W bands. Where possible, we use these parallel fields to derive tip of the red giant branch (TRGB) distances to these galaxies. In this paper, we present TRGB distances for 11 galaxies from ~4 to ~15 Mpc, based on the first year of PHANGS-HST observations. Five of these represent the first published TRGB distance measurements (IC 5332, NGC 2835, NGC 4298, NGC 4321, and NGC 4328), and eight of which are the best available distances to these targets. We also provide a compilation of distances for the 118 galaxies in the full PHANGS sample, which have been adopted for the first PHANGS-ALMA public data release.