Are the Milky Way and Andromeda unusual? A comparison with Milky Way and Andromeda Analogs

Abstract

Our Milky Way provides a unique test case for galaxy evolution models, thanks to our privileged position within the Milky Way's disc. This position also complicates comparisons between the Milky Way and external galaxies, due to our inability to observe the Milky Way from an external point of view. Milky Way analog galaxies offer us a chance to bridge this divide by providing the external perspective that we otherwise lack. However, over-precise definitions of "analog" yield little-to-no galaxies, so it is vital to understand which selection criteria produce the most meaningful analog samples. To address this, we compare the properties of complementary samples of Milky Way analogs selected using different criteria. We find the Milky Way to be within 1$\sigma$ of its analogs in terms of star-formation rate and bulge-to-total ratio in most cases, but we find larger offsets between the Milky Way and its analogs in terms of disc scale length; this suggests that scale length must be included in analog selections in addition to other criteria if the most accurate analogs are to be selected. We also apply our methodology to the neighbouring Andromeda galaxy. We find analogs selected on the basis of strong morphological features to display much higher star-formation rates than Andromeda, and we also find analogs selected on Andromeda's star-formation rate to over-predict Andromeda's bulge extent. This suggests both structure and star-formation rate should be considered when selecting the most stringent Andromeda analogs.

13 pages, 11 figures. Accepted by MNRAS

References in corpus (37)

• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• UV Star Formation Rates in the Local Universe
• The Radial Velocity Experiment (RAVE): first data release
• The GALAH Survey: Scientific Motivation
• GALEX-SDSS-WISE Legacy Catalog (GSWLC): Star Formation Rates, Stellar Masses and Dust Attenuations of 700,000 Low-redshift Galaxies
• The Gaia-ESO Survey: the Galactic Thick to Thin Disc transition
• The long bar as seen by the VVV survey: I. Colour-magnitude diagrams
• Tracing chemical evolution over the extent of the Milky Way's Disk with APOGEE Red Clump Stars
• On the Formation of Galactic Thick Disks
• The age-metallicity structure of the Milky Way disk
• Origin of chemically distinct discs in the Auriga cosmological simulations
• Galaxy Zoo: comparing the demographics of spiral arm number and a new method for correcting redshift bias
• The Gaia-ESO Survey: the chemical structure of the Galactic discs from the first internal data release
• Galaxy Zoo: Evidence for Diverse Star Formation Histories through the Green Valley
• Galaxy Zoo: Secular evolution of barred galaxies from structural decomposition of multi-band images
• The Near-infrared S0 Survey III: Morphology of 15 Southern Early-type Disk Galaxies
• SDSS IV MaNGA - The spatially resolved transition from star formation to quiescence
• The SAMI Galaxy Survey: Global stellar populations on the size-mass plane
• A radial age gradient in the geometrically thick disk of the Milky Way
• Unveiling the Boxy Bulge and Bar of the Andromeda Spiral Galaxy
• The Nature and Origin of Substructure in the Outskirts of M31 -- II. Detailed Star Formation Histories
• Ages and masses of million Galactic disk main sequence turn-off and sub-giant stars from the LAMOST Galactic spectroscopic surveys
• An Ultraviolet Study of Star-Forming Regions in M31
• Ages and Masses of 0.64 million Red Giant Branch stars from the LAMOST Galactic Spectroscopic Survey
• Age Demographics of the Milky Way Disk and Bulge
• The bimodal [Mg/Fe] versus [Fe/H] bulge sequence as revealed by APOGEE DR14
• Box/Peanut and Bar structures in edge-on and face-on SDSS nearby galaxies I. Catalogue
• A Global Star Forming Episode in M31 2-4 Gyr Ago
• Scalelength of disc galaxies
• Does the Milky Way Obey Spiral Galaxy Scaling Relations?
• Milky Way Analogues in MaNGA: Multi-Parameter Homogeneity and Comparison to the Milky Way
• Sizing Up the Milky Way: A Bayesian Mixture Model Meta-Analysis of Photometric Scale Length Measurements
• The scaling relation between baryonic mass and stellar disc size of morphologically late-type galaxies
• The Milky Way and Andromeda galaxies in a constrained hydrodynamical simulation: morphological evolution
• The Effect of Bars on the Ionized ISM: Optical Emission Lines from Milky Way Analogs
• On the Mass Assembly History of the Local Group
• Probing Galactic Structure with the Spatial Correlation Function of SEGUE G-dwarf Stars

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• Mapping the Galactic Metallicity Gradient with Open Clusters: The State-of-the-Art and Future Challenges
• The merger and assembly histories of Milky Way- and M31-like galaxies with TNG50: disk survival through mergers
• The Milky Way tomography with APOGEE: intrinsic density distribution and structure of mono-abundance populations
• SDSS IV MaNGA: Bar pattern speed in Milky Way Analogue galaxies
• Cold and Hot gas distribution around the Milky-Way-M31 system in the HESTIA simulations
• Searching for Milky Way twins: Radial abundance distribution as a strict criterion
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• A Galactic Self-Portrait: Density Structure and Integrated Properties of the Milky Way Disk
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