Comparing M31 and Milky Way Satellites: The Extended Star Formation Histories of Andromeda II and Andromeda XVI

Abstract

We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys aboard the Hubble Space Telescope, we obtained deep optical imaging of Andromeda II (M${}_V=-$12.0; log(M${}_{\star }$/M${}_{\odot }$) $\sim$ 6.7) and Andromeda XVI (M${}_V=-$7.5; log(M${}_{\star }$/M${}_{\odot }$) $\sim$ 4.9) yielding color-magnitude diagrams that extend at least 1 magnitude below the oldest main sequence turnoff, and are similar in quality to those available for the MW companions. And II and And XVI show strikingly similar SFHs: both formed 50-70% of their total stellar mass between 12.5 and 5 Gyr ago (z$\sim$5-0.5) and both were abruptly quenched $\sim$ 5 Gyr ago (z$\sim$0.5). The predominance of intermediate age populations in And XVI makes it qualitatively different from faint companions of the MW and clearly not a pre-reionization fossil. Neither And II nor And XVI appears to have a clear analog among MW companions, and the degree of similarity in the SFHs of And II and And XVI is not seen among comparably faint-luminous pairs of MW satellites. These findings provide hints that satellite galaxy evolution may vary substantially among hosts of similar stellar mass. Although comparably deep observations of more M31 satellites are needed to further explore this hypothesis, our results underline the need for caution when interpreting satellite galaxies of an individual system in a broader cosmological context.

arXiv comment7 pages, 4 Figures. Accepted for publication in ApJ

References in corpus (59)

• Astropy: A Community Python Package for Astronomy
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Planck 2013 results. XVI. Cosmological parameters
• The observed properties of dwarf galaxies in and around the Local Group
• A large stellar evolution database for population synthesis studies. I. Scaled solar models and isochrones
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• Theoretical isochrones in several photometric systems I. Johnson-Cousins-Glass, HST/WFPC2, HST/NICMOS, Washington, and ESO Imaging Survey filter sets
• Star Formation Histories, Abundances and Kinematics of Dwarf Galaxies in the Local Group
• WFPC2 Stellar Photometry with HSTphot
• The Field of Streams: Sagittarius and its Siblings
• The remnants of galaxy formation from a panoramic survey of the region around M31
• Numerical Methods of Star Formation History Measurement and Applications to Seven Dwarf Spheroidals
• A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy
• The Star Formation Histories of Local Group Dwarf Galaxies I. Hubble Space Telescope / Wide Field Planetary Camera 2 Observations
• The Metamorphosis of Tidally Stirred Dwarf Galaxies
• Two distinct ancient components in the Sculptor Dwarf Spheroidal Galaxy: First Results from DART
• The VPOS: a vast polar structure of satellite galaxies, globular clusters and streams around the Milky Way
• The ACS Nearby Galaxy Survey Treasury IX. Constraining asymptotic giant branch evolution with old metal-poor galaxies
• Multi-Element Abundance Measurements from Medium-Resolution Spectra. III. Metallicity Distributions of Milky Way Dwarf Satellite Galaxies
• Too Big to Fail in the Local Group
• Formation Histories of Dwarf Galaxies in the Local Group
• Mapping the stellar structure of the Milky Way thick disk and halo using SEGUE photometry
• The ACS LCID project. III. The star formation history of the Cetus dSph galaxy: a post-reionization fossil
• Structural parameters for the M31 dwarf spheroidals
• A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude (Part II); Distances to the Satellites of M31
• The Detailed Star Formation History in the Spheroid, Outer Disk, and Tidal Stream of the Andromeda Galaxy
• The SPLASH Survey: Spectroscopy of 15 M31 Dwarf Spheroidal Satellite Galaxies
• The ACS LCID project. V. The Star Formation History of the Dwarf Galaxy \objectname[]{LGS-3}: Clues for Cosmic Reionization and Feedback
• The Space Motion of Leo I: Hubble Space Telescope Proper Motion and Implied Orbit
• The Primeval Populations of the Ultra-Faint Dwarf Galaxies
• Infall Times for Milky Way Satellites From Their Present-Day Kinematics
• The SPLASH Survey: Internal Kinematics, Chemical Abundances, and Masses of the Andromeda I, II, III, VII, X, and XIV dSphs
• The PAndAS view of the Andromeda satellite system - I. A Bayesian search for dwarf galaxies using spatial and color-magnitude information
• Does M31 result from an ancient major merger?
• The Impact of Inhomogeneous Reionization on the Satellite Galaxy Population of the Milky Way
• On the Estimation of Systematic Uncertainties of Star Formation Histories
• IAC-pop: Finding the Star Formation History of Resolved Galaxies
• The remnant of a merger between two dwarf galaxies in Andromeda II
• On the Estimation of Random Uncertainties of Star Formation Histories
• The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda I
• The satellites of the Milky Way - Insights from semi-analytic modelling in a LambdaCDM cosmology
• Stellar Kinematics of the Andromeda II Dwarf Spheroidal Galaxy
• The Stellar Populations and Structural Properties of Ultra Faint Dwarf Galaxies, Canes Venatici I, Bootes I, Canes Venatici II, and Leo IV
• Was the Andromeda Stream Produced by a Disk Galaxy?
• The Formation of the Local Group Planes of Galaxies
• Exploring the Properties of the M31 Halo Globular Cluster System
• The masses of Local Group dwarf spheroidal galaxies: The death of the universal mass profile
• The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda II
• The Star Formation History and Dust Content in the Far Outer Disc of M31
• Probing the Epoch of Reionization with Milky Way Satellites
• What Sets the Sizes of the Faintest Galaxies?
• The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda III
• Spatial dependence of the Star Formation History in the Central Regions of the Fornax Dwarf Spheroidal Galaxy
• An HST/ACS View of the Inhomogeneous Outer Halo of M31
• A Deeper Look at Leo IV: Star Formation History and Extended Structure
• Deconstructing dwarf galaxies: a Suprime-Cam survey of Andromeda II
• Tidal Stirring of Disky Dwarfs with Shallow Dark Matter Density Profiles: Enhanced Transformation into Dwarf Spheroidals
• HST/WFPC2 Imaging of the Dwarf Satellites And XI and And XIII : HB Morphology and RR Lyraes
• A Possible Formation Scenario for Dwarf Spheroidal Galaxies - II: A Parameter Study

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• The PAndAS view of the Andromeda satellite system - II. Detailed properties of 23 M31 dwarf spheroidal galaxies
• The ACS LCID Project: On the origin of dwarf galaxy types: a manifestation of the halo assembly bias?
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• The VMC survey - XXXI. The spatially resolved star formation history of the main body of the Small Magellanic Cloud
• The Star Formation Histories of Local Group Dwarf Galaxies III. Characterizing Quenching in Low-Mass Galaxies
• The ISLAndS project II: The Lifetime Star Formation Histories of Six Andromeda dSphs
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• The Suppression of Star Formation on the Smallest Scales: What Role Does Environment Play?
• A detailed study of Andromeda XIX, an extreme local analogue of ultra diffuse galaxies
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• A Hubble Space Telescope Study of the Enigmatic Milky Way Halo Globular Cluster Crater
• Tucana B: A Potentially Isolated and Quenched Ultra-faint Dwarf Galaxy at D$\approx$1.4 Mpc
• The star formation histories of dwarf galaxies in Local Group cosmological simulations
• The ISLAnds Project III: Variable Stars in Six Andromeda Dwarf Spheroidal Galaxies
• Satellites of Milky Way- and M31-like galaxies with TNG50: quenched fractions, gas content, and star formation histories
• Toward an internally consistent astronomical distance scale
• Elemental Abundances in M31: First Alpha and Iron Abundance Measurements in M31's Giant Stellar Stream
• The ISLANDS project I: Andromeda XVI, An Extremely Low Mass Galaxy not Quenched by Reionization
• Andromeda II as a merger remnant
• A model for the minimum mass of bound stellar clusters and its dependence on the galactic environment
• A rogues gallery of Andromeda's dwarf galaxies I. A predominance of red horizontal branches
• Elemental abundances in M31: [Fe/H] and [α/Fe] in M31 Dwarf Galaxies Using Coadded Spectra
• The Isaac Newton Telescope monitoring survey of Local Group dwarf galaxies. I. Survey overview and first results for Andromeda I
• The imprint of clump formation at high redshift. II. The chemistry of the bulge
• Reionization of the Milky Way, M31, and their satellites I: reionization history and star formation
• Constraining the nature of dark matter with the star formation history of the faintest Local Group dwarf galaxy satellites
• Harnessing the Hubble Space Telescope Archives: A Catalogue of 21,926 Interacting Galaxies
• A detailed star formation history for the extremely diffuse Andromeda XIX dwarf galaxy
• The dynamics of Andromeda's dwarf galaxies and stellar streams
• Andromeda XXXV: The Faintest Dwarf Satellite of the Andromeda Galaxy