The Hubble Space Telescope Survey of M31 Satellite Galaxies I. RR Lyrae-based Distances and Refined 3D Geometric Structure

Abstract

We measure homogeneous distances to M31 and 38 associated stellar systems ($-$16.8$\le M_V\le$ $-$6.0), using time-series observations of RR Lyrae stars taken as part of the Hubble Space Telescope Treasury Survey of M31 Satellites. From $>700$ orbits of new/archival ACS imaging, we identify $>4700$ RR Lyrae stars and determine their periods and mean magnitudes to a typical precision of 0.01 days and 0.04 mag. Based on Period-Wesenheit-Metallicity relationships consistent with the Gaia eDR3 distance scale, we uniformly measure heliocentric and M31-centric distances to a typical precision of $\sim 20$ kpc (3%) and $\sim 10$ kpc (8%), respectively. We revise the 3D structure of the M31 galactic ecosystem and: (i) confirm a highly anisotropic spatial distribution such that $\sim 80$% of M31's satellites reside on the near side of M31; this feature is not easily explained by observational effects; (ii) affirm the thin (rms $7-23$ kpc) planar "arc" of satellites that comprises roughly half (15) of the galaxies within 300 kpc from M31; (iii) reassess physical proximity of notable associations such as the NGC 147/185 pair and M33/AND XXII; and (iv) illustrate challenges in tip-of-the-red-giant branch distances for galaxies with $M_V>-9.5$, which can be biased by up to 35%. We emphasize the importance of RR Lyrae for accurate distances to faint galaxies that should be discovered by upcoming facilities (e.g., Rubin Observatory). We provide updated luminosities and sizes for our sample. Our distances will serve as the basis for future investigation of the star formation and orbital histories of the entire known M31 satellite system.

32 pages, 15 figures, accepted for publication on ApJ

References in corpus (73)

• The NumPy array: a structure for efficient numerical computation
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions
• Cosmic Distances Calibrated to 1% Precision with Gaia EDR3 Parallaxes and Hubble Space Telescope Photometry of 75 Milky Way Cepheids Confirm Tension with LambdaCDM
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• The ACS Nearby Galaxy Survey Treasury
• Beasts of the Southern Wild: Discovery of nine Ultra Faint satellites in the vicinity of the Magellanic Clouds
• A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy
• The Haunted Halos of Andromeda and Triangulum: A panorama of galaxy formation in action
• The Quenching of the Ultra-Faint Dwarf Galaxies in the Reionization Era
• Is the SMC Bound to the LMC? The HST Proper Motion of the SMC
• Exoplanet population inference and the abundance of Earth analogs from noisy, incomplete catalogs
• Legacy ExtraGalactic UV Survey (LEGUS) with The Hubble Space Telescope. I. Survey Description
• The Panchromatic Hubble Andromeda Treasury X. Ultraviolet to Infrared Photometry of 117 Million Equidistant Stars
• The spatial distribution of the Milky Way and Andromeda satellite galaxies
• Discovery and analysis of three faint dwarf galaxies and a globular cluster in the outer halo of the Andromeda galaxy
• The SAGA Survey. II. Building a Statistical Sample of Satellite Systems around Milky Way-like Galaxies
• Tip of the Red Giant Branch Distances. I. Optimization of a Maximum Likelihood Algorithm
• The Metal-Poor Halo of the Andromeda Spiral Galaxy (M31)
• The PAndAS view of the Andromeda satellite system - II. Detailed properties of 23 M31 dwarf spheroidal galaxies
• A trio of new Local Group galaxies with extreme properties
• Discovery of New Dwarf Galaxies in the M81 Group
• The Gas Content and Stripping of Local Group Dwarf Galaxies
• Orbits of Massive Satellite Galaxies: I. A Close Look at the Large Magellanic Cloud and a New Orbital History for M33
• The DECam Local Volume Exploration Survey: Overview and First Data Release
• The Parallax of Omega Centauri Measured from Gaia EDR3 and a Direct, Geometric Calibration of the Tip of the Red Giant Branch and the Hubble Constant
• Satellite Dwarf Galaxies in a Hierarchical Universe: The Prevalence of Dwarf-Dwarf Major Mergers
• On the distance of the globular cluster M4 (NGC 6121) using RR Lyrae stars: I. optical and near-infrared Period-Luminosity and Period-Wesenheit relations
• Global Properties of M31's Stellar Halo from the SPLASH Survey: II. Metallicity Profile
• The Nature and Origin of Substructure in the Outskirts of M31 -- II. Detailed Star Formation Histories
• Planes of satellites around Milky Way/M31-mass galaxies in the FIRE simulations and comparisons with the Local Group
• Andromeda XVII: A New Low Luminosity Satellite of M31
• Standard Galactic Field RR Lyrae. I. Optical to Mid-infrared Phased Photometry
• The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER) I. Ultraviolet to Infrared Photometry of 22 Million Stars in M33
• The Distribution of Alpha Elements in Andromeda Dwarf Galaxies
• The age of the Milky Way inner stellar spheroid from RR Lyrae population synthesis
• Clustering of Local Group distances: publication bias or correlated measurements? II. M31 and beyond
• Elemental Abundances in M31: The Kinematics and Chemical Evolution of Dwarf Spheroidal Satellite Galaxies
• Standard Galactic Field RR Lyrae II: A Gaia DR2 calibration of the period-Wesenheit-metallicity relation
• HST Proper Motions of NGC 147 and NGC 185: Orbital Histories and Test of Dynamically Coherent Andromeda Satellite Plane
• A PAndAS view of M31 dwarf elliptical satellites: NGC147 and NGC185
• Relative distances of Omega Centauri and 47 Tucanae
• The ACS LCID Project: RR Lyrae stars as tracers of old population gradients in the isolated dwarf spheroidal galaxy Tucana
• A sub-2% Distance to M31 from Photometrically Homogeneous Near-Infrared Cepheid Period-Luminosity Relations Measured with the Hubble Space Telescope
• Comparing the Quenching Times of Faint M31 and Milky Way Satellite Galaxies
• Tucana B: A Potentially Isolated and Quenched Ultra-faint Dwarf Galaxy at D$\approx$1.4 Mpc
• Two major accretion epochs in M31 from two distinct populations of globular clusters
• The Lopsidedness of Satellite Galaxy Systems in $\Lambda$CDM simulations
• Star formation histories of the LEGUS dwarf galaxies (III): the non-bursty nature of 23 star forming dwarf galaxies
• The ISLAnds Project III: Variable Stars in Six Andromeda Dwarf Spheroidal Galaxies
• 3D hydrodynamic simulations for the formation of the Local Group satellite planes
• On the Stability of Satellite Planes I: Effects of Mass, Velocity, Halo Shape and Alignment
• New LZ and PW(Z) relations of RR Lyrae stars calibrated with Gaia EDR3 parallaxes
• Variable stars and stellar populations in Andromeda XXV: III. A central cluster or the galaxy nucleus?
• RR Lyrae-based Distances for 39 Nearby Dwarf Galaxies Calibrated to Gaia eDR3
• Pegasus V -- a newly discovered ultra-faint dwarf galaxy on the outskirts of Andromeda
• Elemental Abundances in M31: Gradients in the Giant Stellar Stream
• Stellar population and structural properties of dwarf galaxies and young stellar systems in the M81 group
• A Hybrid Algorithm for Period Analysis from Multi-band Data with Sparse and Irregular Sampling for Arbitrary Light Curve Shapes
• Star formation history of And XVIII: a dwarf spheroidal galaxy in isolation
• Dust in the outskirts of M31 and M33
• Elemental abundances in M31: [Fe/H] and [α/Fe] in M31 Dwarf Galaxies Using Coadded Spectra
• Lopsided Satellite Distributions around Isolated Host Galaxies
• An updated detailed characterization of planes of satellites in the MW and M31
• DDO216-A1: a central globular cluster in a low-luminosity transition type galaxy
• The PAndAS View of the Andromeda Satellite System. III. Dwarf galaxy detection limits
• The lopsided distribution of satellites of isolated central galaxies
• A theoretical scenario for Galactic RR Lyrae in the Gaia database: constraints on the parallax offset
• Stability of Satellite Planes in M31 II: Effects of the Dark Subhalo Population
• Distances to Local Group Galaxies via Population II, Stellar Distance Indicators. II. The Fornax Dwarf Spheroidal
• Kinematics and Metallicity of Red Giant Branch Stars in the Northeast Shelf of M31
• On the origin of the asymmetric dwarf galaxy distribution around Andromeda

Cited by in corpus (27)

• CHAOS VII: A Large-Scale Direct Abundance Study in M33
• Pegasus W: An Ultra-Faint Dwarf Galaxy Outside the Halo of M31 Not Quenched by Reionization
• Evidence for a Massive Andromeda Galaxy Using Satellite Galaxy Proper Motions
• The PAndAS View of the Andromeda Satellite System. IV Global properties
• The imprint of galaxy mergers on satellite planes in a cosmological context
• Clusters, Clouds, and Correlations: Relating Young Clusters to Giant Molecular Clouds in M33 and M31
• On the Reionization-Era Globular Cluster in Low-Mass Galaxy Eridanus II
• The Tucana dwarf spheroidal: a distant backsplash galaxy of M31?
• The Karl G. Jansky Very Large Array Local Group L-band Survey (LGLBS)
• LMC-driven anisotropic boosts in stream--subhalo interactions
• HubPUG: Proper Motions for Local Group Dwarfs observed with HST utilizing Gaia as a Reference Frame
• Andromeda XXV -- a dwarf galaxy with a low central dark matter density
• Lopsided distribution of MATLAS and ELVES dwarf satellite systems around isolated host galaxies
• Mass Modeling the Andromeda Dwarf Galaxies: Andromeda VI and Andromeda XXIII
• The emergence of globular clusters and globular-cluster-like dwarfs
• Disappearance of a massive star in the Andromeda Galaxy due to formation of a black hole
• Andromeda's asymmetric satellite system as a challenge to cold dark matter cosmology
• Line-of-sight mass estimator and the masses of the Milky Way and Andromeda Galaxy
• The frozen outskirts: a cold Hubble flow and the mass of the Local Group
• Pulsar discovery prospect of FASTA
• Andromeda XXXV: The Faintest Dwarf Satellite of the Andromeda Galaxy
• DELVE Milky Way Satellite Galaxy Census I: Satellite Population and Survey Selection Function in DES, DELVE, and Pan-STARRS
• RR Lyrae stars with variable mean magnitudes
• Testing a proposed "planarity" tool for studying satellite systems: On the alleged consistency of Milky Way satellite galaxy planes with $\Lambda$CDM
• A Low Metallicity Massive Contact Binary Star System Candidate in WLM identified by Hubble and James Webb Space Telescope imaging
• SIGNALS of Giant HII Regions: A Spatially Resolved Analysis of NGC 604
• Calibrating the Tip of the Red Giant Branch and measuring Magellanic Cloud distances to 2% exclusively with Gaia