Distances to PHANGS galaxies: New tip of the red giant branch measurements and adopted distances

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, H ii 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.

PHANGS–ALMA Data Processing and Pipeline

“…In total, in the public data release, 81 galaxies have 12 m+7 m+TP data and and 90 have 7 m+TP. c When convolving to a fixed physical resolution, we adopt the current best estimate of the galaxy's distance (from Anand et al (2021), for PHANGS-ALMA).…”

“…We use Euclidean geometry for this calculation. For PHANGS-ALMA, we adopt the distances derived and compiled by Anand et al (2021). For these target angular resolutions, the 12 m+7 m data can typically be convolved to all scales.…”

“…Table 3 and Figure 2021), among many others. After accounting for the current best-estimate distances to the targets (Anand et al 2021), the 7 m+TP data show a wide range of physical resolutions, typically ∼550 pc but with outliers down to <200 pc. These high resolutions arise from 7 m observations of very nearby systems with d  5 Mpc, many of which we have so far targeted only with the ACA.…”

PHANGS–HST: star cluster spectral energy distribution fitting with cigale

“…This paper is part of a series which documents the major components of the overall PHANGS-HST data products pipeline: survey design and implementation (Lee et al 2021); source detection and selection of compact star cluster candidates (Thilker et al, in preparation); aperture correction and quantitative morphologies of star clusters (Deger et al, in preparation); star cluster candidate classification (Whitmore et al, in preparation); neural network classification proof-of-concept demonstration (Wei et al 2020); stellar association identification and analysis (Larson et al, in preparation); and constraints on galaxy distances through analysis of the Tip of the Red Giant Branch as observed in the PHANGS-HST parallel pointings (Anand et al 2020).…”

“…Galaxies that are relatively face-on, avoid the Galactic plane, and have robust molecular cloud populations to facilitate joint analysis of resolved stellar populations and molecular clouds(Anand et al 2020;Lee et al 2021).5 There are a number of SFH and SSP modules available by default within CIGALE. The SFH modules included are a double exponential, a delayed SFH with optional exponential burst or constant burst/quench, a periodic SFH, and a user specified SFH read in from an input file.…”