The Milky Way bar and bulge revealed by APOGEE DR16 and Gaia EDR3

Abstract

We investigate the inner regions of the Milky Way with a sample of unprecedented size and coverage thanks to APOGEE DR16 and Gaia EDR3 data. Our inner Galactic sample has more than 26,000 stars within $|X_{\mathrm{Gal}}|<5$ kpc, $|Y_{\mathrm{Gal}}|<3.5$ kpc, $|Z_{\mathrm{Gal}}|<1$ kpc, and we also make the analysis for a foreground-cleaned sub-sample of 8,000 stars more representative of the bulge-bar populations. The inner Galaxy shows a clear chemical discontinuity in key abundance ratios [$\alpha$/Fe], [C/N], and [Mn/O], probing different enrichment timescales, which suggests a star formation gap (quenching) between the high- and low-$\alpha$ populations. For the first time, we are able to fully characterize the different populations co-existing in the innermost regions of the Galaxy via joint analysis of the distributions of rotational velocities, metallicities, orbital parameters and chemical abundances. The chemo-kinematic analysis reveals the presence of the bar; of an inner thin disk; of a thick disk, and of a broad metallicity population, with a large velocity dispersion, indicative of a pressure supported component. We find and characterize chemically and kinematically a group of counter-rotating stars, which could be the result of a gas-rich merger event or just the result of clumpy star formation during the earliest phases of the early disk, which migrated into the bulge. Finally, based on the 6D information we assign stars a probability value of being on a bar orbit and find that most of the stars with large bar orbit probabilities come from the innermost 3 kpcs. Even stars with a high probability of belonging to the bar show the chemical bimodality in the [$\alpha$/Fe] vs. [Fe/H] diagram. This suggests bar trapping to be an efficient mechanism, explaining why stars on bar orbits do not show a significant distinct chemical abundance ratio signature.

arXiv comment25 pages, 25 figures, Accepted for publication on A&A, in press

References in corpus (170)

• Astropy: A Community Python Package for Astronomy
• A Universal Density Profile from Hierarchical Clustering
• Gaia Data Release 2. Summary of the contents and survey properties
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The 2.5 m Telescope of the Sloan Digital Sky Survey
• SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems
• Local Kinematics and the Local Standard of Rest
• The Apache Point Observatory Galactic Evolution Experiment (APOGEE)
• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
• The Sixteenth Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
• The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
• VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
• Gaia Early Data Release 3: Parallax bias versus magnitude, colour, and position
• The Chemical Evolution of the Galaxy: the two-infall model
• ASPCAP: The Apogee Stellar Parameter and Chemical Abundances Pipeline
• The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
• Chemical Cartography with APOGEE: Metallicity Distribution Functions and the Chemical Structure of the Milky Way Disk
• Gaia Data Release 2: Catalogue validation
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• Evidence for Two Early Accretion Events That Built the Milky Way Stellar Halo
• The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
• APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South
• The Birth of a Galaxy: Primordial Metal Enrichment and Stellar Populations
• Chemodynamical evolution of the Milky Way disk I: The solar vicinity
• Age and Metallicity Distribution of the Galactic Bulge from Extensive Optical and Near-IR Stellar Photometry
• Vertical waves in the solar neighbourhood in Gaia DR2
• VVV DR1: The First Data Release of the Milky Way Bulge and Southern Plane from the Near-Infrared ESO Public Survey VISTA Variables in the Via Lactea
• Target Selection for the Apache Point Observatory Galactic Evolution Experiment (APOGEE)
• Dynamical modelling of the Galactic bulge and bar: the Milky Way's bar pattern speed, stellar, and dark matter mass distribution
• Origin and structure of the Galactic disc(s)
• The Metal Content of Bulge Field Stars from FLAMES-GIRAFFE Spectra. I. Stellar parameters and Iron Abundances
• Bulge Formation by the Coalescence of Giant Clumps in Primordial Disk Galaxies
• ARGOS III: Stellar Populations in the Galactic Bulge of the Milky Way
• The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs
• Evidence for Mature Bulges and an Inside-out Quenching Phase 3 Billion Years After the Big Bang
• Two Red Clumps and the X-Shaped Milky Way Bulge
• The Biggest Splash
• Target Selection for the SDSS-IV APOGEE-2 Survey
• The Brown Dwarf Kinematics Project (BDKP) I. Proper Motions and Tangential Velocities for a Large Sample of Late-type M, L and T Dwarfs
• Abundances of Baade's Window Giants from Keck/HIRES Spectra: II. The Alpha- and Light Odd Elements
• APOGEE Data Releases 13 and 14: Data and Analysis
• Oxygen, Carbon and Nitrogen evolution in galaxies
• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18
• A Parallax Distance to the Microquasar GRS 1915+105 and a Revised Estimate of its Black Hole Mass
• Red giant masses and ages derived from carbon and nitrogen abundances
• Chemodynamical evolution of the Milky Way disk II: Variations with Galactic radius and height above the disk plane
• The Bulge Radial Velocity Assay (BRAVA): II. Complete Sample and Data Release
• The Split Red Clump of the Galactic Bulge from OGLE-III
• The metallicity distribution of bulge clump giants in Baade's Window
• Star formation in a galactic outflow
• StarHorse: A Bayesian tool for determining stellar masses, ages, distances, and extinctions for field stars
• Evidence from APOGEE for the presence of a major building block of the halo buried in the inner Galaxy
• Using chemical tagging to redefine the interface of the Galactic disk and halo
• Life in the fast lane: a direct view of the dynamics, formation, and evolution of the Milky Way's bar
• Chemodynamics of the Milky Way. I. The first year of APOGEE data
• Chemodynamical history of the Galactic Bulge
• Tracing chemical evolution over the extent of the Milky Way's Disk with APOGEE Red Clump Stars
• ARGOS IV: The Kinematics of the Milky Way Bulge
• Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. VI. Age and abundance structure of the stellar populations in the central sub-kpc of the Milky Way
• Age dissection of the Milky Way discs: red giants in the Kepler field
• Chemistry of the Sagittarius Dwarf Galaxy: a Top-Light IMF, Outflows and the R-Process
• Chemical Cartography with APOGEE: Large-scale Mean Metallicity Maps of the Milky Way
• On the origin of the chemical bimodality of disk stars: A tale of merger and migration
• From the bulge to the outer disc: StarHorse stellar parameters, distances, and extinctions for stars in APOGEE DR16 and other spectroscopic surveys
• Separation of Stellar Populations by an Evolving Bar: Implications for the Bulge of the Milky Way
• Deciphering the 3D structure of the old Galactic bulge from the OGLE RR Lyrae stars
• Kinematics of SDSS subdwarfs: Structure and substructure of the Milky Way halo
• Confirmation of the $Gaia$ DR2 parallax zero-point offset using asteroseismology and spectroscopy in the $Kepler$ field
• Carbon, nitrogen and $\alpha$-element abundances determine the formation sequence of the Galactic thick and thin disks
• Insights on the Milky Way bulge formation from the correlations between kinematics and metallicity
• The Sixth Data Release of the Radial Velocity Experiment (RAVE) -- II: Stellar Atmospheric Parameters, Chemical Abundances and Distances
• EDGE: the mass-metallicity relation as a critical test of galaxy formation physics
• The GIRAFFE Inner Bulge Survey (GIBS) III. Metallicity distributions and kinematics of 26 Galactic bulge fields
• Chemodynamics of barred galaxies in cosmological simulations: On the Milky Way's quiescent merger history and in-situ bulge
• Red giants observed by CoRoT and APOGEE: The evolution of the Milky Way's radial metallicity gradient
• The pattern speed of the Milky Way bar from transverse velocities
• Ages and kinematics of chemically selected, accreted Milky Way halo stars
• The Gaia-ESO Survey: metallicity and kinematic trends in the Milky Way bulge
• VVV Survey Near-Infrared Photometry of Known Bulge RR Lyrae stars: the Distance to the Galactic Center and Absence of a Barred Distribution of the Metal-Poor Population
• The GIRAFFE Inner Bulge Survey (GIBS). I. Survey Description and a kinematical map of the Milky Way bulge
• Chemical Cartography with APOGEE: Multi-element abundance ratios
• The shape of the Galactic halo with $Gaia$ DR2 RR Lyrae. Anatomy of an ancient major merger
• Galactic spiral structure revealed by Gaia EDR3
• The Bulge Radial Velocity Assay (BRAVA): I. Techniques and a Rotation Curve
• The Gaia-ESO Survey: Exploring the complex nature and origins of the Galactic bulge populations
• The origin and evolution of the odd-Z iron-peak elements Sc, V, Mn, and Co in the Milky Way stellar disk
• Chronologically dating the early assembly of the Milky Way
• A New Photometric Model of the Galactic Bar using Red Clump Giants
• Sausage & Mash: The dual origin of the Galactic thick disc and halo from the gas-rich Gaia-Enceladus-Sausage merger
• Revisiting the Tale of Hercules: how stars orbiting the Lagrange points visit the Sun
• Reddening and metallicity maps of the Milky Way bulge from VVV and 2MASS III. The first global photometric metallicity map of the Galactic bulge
• Widespread star formation inside galactic outflows
• Chemical Evolution of the Galactic Bulge as Derived from High-Resolution Infrared Spectroscopy of K and M Red Giants
• Low-Velocity Streams in the Solar Neighborhood Caused by the Galactic Bar
• Chemical Enrichment and Radial Migration in the Galactic Disk -- the origin of the [$\alpha /\mathrm{Fe}]$ Double Sequence
• Spectro-photometric distances to stars: a general-purpose Bayesian approach
• The Gravitational Force Field of the Galaxy Measured From the Kinematics of RR Lyrae in Gaia
• New Constraints on the Galactic Bar
• Before the Bar: Kinematic Detection of A Spheroidal Metal-Poor Bulge Component
• Fluctuations in galactic bar parameters due to bar-spiral interaction
• A radial age gradient in the geometrically thick disk of the Milky Way
• APOGEE DR16: a multi-zone chemical evolution model for the Galactic disc based on MCMC methods
• Peanuts, brezels and bananas: food for thought on the orbital structure of the Galactic bulge
• Evidence of a dynamically evolving Galactic warp
• Detailed abundances for M giants in two inner bulge fields from Infrared Spectroscopy
• The Pristine Inner Galaxy Survey (PIGS) I: Tracing the kinematics of metal-poor stars in the Galactic bulge
• VLT-FLAMES Analysis of 8 giants in the Bulge Metal-poor Globular Cluster NGC 6522: Oldest Cluster in the Galaxy?
• How Many Components? Quantifying the Complexity of the Metallicity Distribution in the Milky Way Bulge with APOGEE
• Stellar migrations and metal flows -- Chemical evolution of the thin disc of a simulated Milky Way analogous galaxy
• Star formation history of the Galactic bulge from deep HST imaging of low reddening windows
• Bulge growth through disk instabilities in high-redshift galaxies
• Metallicity Distribution Functions, Radial Velocities, and Alpha Element Abundances in Three Off-Axis Bulge Fields
• APOGEE Kinematics I: Overview of the Kinematics of the Galactic Bulge as Mapped by APOGEE
• APOGEE DR14/DR15 Abundances in the Inner Milky Way
• High-resolution abundance analysis of red giants in the globular cluster NGC 6522
• Field Stars and Clusters of the Galactic Bulge: Implications for Galaxy Formation
• The Giraffe Inner Bulge Survey (GIBS) II. Metallicity distributions and alpha element abundances at fixed Galactic latitude
• The Vertical X-shaped Structure in the Milky Way: Evidence from a Simple Boxy Bulge Model
• The Gaia-ESO survey: impact of extra-mixing on C- and N-abundances of giant stars
• The age of the Milky Way inner stellar spheroid from RR Lyrae population synthesis
• The quiescent phase of galactic disc growth
• The WFC3 Galactic Bulge Treasury Program: Relative Ages of Bulge Stars of High and Low Metallicity
• The relation between chemical abundances and kinematics of the Galactic disc with RAVE
• Gaia kinematics reveal a complex lopsided and twisted Galactic disc warp
• The Bulge Radial Velocity Assay for RR Lyrae stars (BRAVA-RR) DR2: a Bimodal Bulge?
• A Deep View of a Fossil Relic in the Galactic Bulge: The Globular Cluster HP1
• The Splash without a merger
• Stellar Masses of Giant Clumps in CANDELS and Simulated Galaxies Using Machine Learning
• The origin of stellar populations in the Galactic bulge from chemical abundances
• Kinematics with Gaia DR2: The Force of a Dwarf
• Proper Motion Dispersions of Red Clump Giants in the Galactic Bulge: Observations and Model Comparisons
• A lack of classical Cepheids in the inner part of the Galactic disk
• Metallicity and kinematics of the bar in-situ
• The inner two degrees of the Milky Way. Evidence of a chemical difference between the Galactic Center and the surrounding inner bulge stellar populations
• Chemo-dynamical properties of the Anticenter Stream: a surviving disc fossil from a past satellite interaction
• Transverse kinematics of the Galactic bar-bulge from VVV and Gaia
• Exploring the stellar age distribution of the Milky Way Bulge using APOGEE
• The bimodal [Mg/Fe] versus [Fe/H] bulge sequence as revealed by APOGEE DR14
• The Bulge Metallicity Distribution from the APOGEE Survey
• Ages of the Bulge globular clusters NGC 6522 and NGC 6626 (M28) from HST Proper-motion-cleaned Color-Magnitude Diagrams
• The Metallicity Distribution of the Milky Way Bulge
• The COMBS Survey -- II. Distinguishing the Metal-Poor Bulge from the Halo Interlopers
• Detailed abundances in the Galactic center: Evidence of a metal-rich alpha-enhanced stellar population
• Manganese abundances in Galactic bulge red giants
• Aluminum Enhanced Metal-Poor Stars buried in the Inner Galaxy
• Mapping the stellar age of the Milky Way bulge with the VVV. I. The method
• The Stellar Halo in the Inner Milky Way: Predicted Shape and Kinematics
• The VVV Survey RR Lyrae Population in the Galactic Centre Region
• Discovery of a new stellar sub-population residing in the (inner) stellar halo of the Milky Way
• Galactic Bar Resonances Inferred from Kinematically Hot Stars in Gaia EDR3
• The Initial Mass Function of the Inner Galaxy Measured From OGLE-III Microlensing Timescales
• The Milky Way's bulge star formation history as constrained from its bimodal chemical abundance distribution
• H-band discovery of additional Second-Generation stars in the Galactic Bulge Globular Cluster NGC 6522 as observed by APOGEE and Gaia
• APOGEE [C/N] Abundances Across the Galaxy: Migration and Infall from Red Giant Ages
• Correlations between kinematics and metallicity in the Galactic bulge: a review
• The K2 Galactic Caps Project -- Going Beyond the \textit{Kepler} Field and Ageing the Galactic Disc
• Dynamical Orbital classification of selected N-rich stars with \textit{Gaia} DR2 astrometry
• Stars behind bars II: A cosmological formation scenario for the Milky Way's central stellar structure
• Kinematics of RR Lyrae stars in the Galactic bulge with OGLE-IV and Gaia DR2
• APOGEE discovery of a chemically atypical star disrupted from NGC 6723 and captured by the Milky Way bulge
• Bulge RR Lyrae stars in the VVV tile $\text{b201}$
• Effects of the selection function on metallicity trends in spectroscopic surveys of the Milky Way
• Another relic bulge globular cluster: ESO 456-SC38 (Djorgovski~2)
• Milky Way demographics with the VVV Survey III. Evidence for a Great Dark Lane in the 157 Million Star Bulge Color-Magnitude Diagram
• Heavy element evolution in the inner regions of the Milky Way
• The relative efficiencies of bars and clumps in driving disc stars to retrograde motion
• Information Theoretic Bounds on Cosmic String Detection in CMB Maps with Noise
• Using the reduced proper motions of Tycho-2 stars with B-V from 0.75 to 1.25: Monte Carlo simulations
• The oldest stars of the bulge: new information on the ancient Galaxy

Cited by in corpus (55)

• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G=18.5
• Gaia Data Release 3: Mapping the asymmetric disc of the Milky Way
• StarHorse results for spectroscopic surveys + Gaia DR3: Chrono-chemical populations in the solar vicinity, the genuine thick disk, and young-alpha rich stars
• Reconstructing the Disrupted Dwarf Galaxy $Gaia$-Sausage/Enceladus Using its Stars and Globular Clusters
• A Tale of Two Disks: Mapping the Milky Way with the Final Data Release of APOGEE
• Spectroscopic age estimates for APOGEE red-giant stars: Precise spatial and kinematic trends with age in the Galactic disc
• The stellar mass distribution of the Milky Way's bar: an analytic model
• The evolution of CNO elements in galaxies
• The stellar mass versus stellar metallicity relation of star-forming galaxies at $1.6\le z\le 3.0$ and implications for the evolution of the $\alpha$-enhancement
• Dynamically constraining the length of the Milky Way bar
• RR Lyrae From Binary Evolution: Abundant, Young and Metal-Rich
• Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost
• Galactic ArchaeoLogIcaL ExcavatiOns (GALILEO) I. An updated census of APOGEE N-rich giants across the Milky Way
• A census of new globular clusters in the Galactic bulge
• The stellar halo in Local Group Hestia simulations III. Chemical abundance relations for accreted and in-situ stars
• The far side of the Galactic bar/bulge revealed through semi-regular variables
• The Milky Way's middle-aged inner ring
• The imprint of clump formation at high redshift. II. The chemistry of the bulge
• Abundance analysis of APOGEE spectra for 58 metal-poor stars from the bulge spheroid
• Modeling the chemical enrichment history of the Bulge Fossil Fragment Terzan 5
• Constructing the Milky Way Stellar Halo in the Galactic Center by Direct Orbit Integration
• The most variable VVV sources: eruptive protostars, dipping giants in the Nuclear Disc and others
• Chrono-chemodynamical analysis of the globular cluster NGC 6355: Looking for the fundamental bricks of the Bulge
• Bayesian inference of three-dimensional gas maps: I. Galactic CO
• The Non-Axisymmetric Influence: Radius and Angle-Dependent Trends in a Barred Galaxy
• Comparing bulge RR Lyrae stars with bulge giants -- Insight from 3D kinematics
• Probing the Milky Way stellar and brown dwarf initial mass function with modern microlensing observations
• A new kinematic model of the Galaxy: analysis of the stellar velocity field from Gaia Data Release 3
• Exploring the Gas-Phase Metallicity Gradients of Star-forming Galaxies at Cosmic Noon
• The Chemodynamics of the Stellar Populations in M31 from APOGEE Integrated Light Spectroscopy
• VVV catalog of ab-type RR Lyrae in the inner Galactic bulge
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data II. Chrono-chemo-kinematics of the disc
• Deciphering the Milky Way disc formation time encrypted in the bar chrono-kinematics
• Mapping the kinematic parameters of the Galaxy from the Gaia EDR3 red giants and sub-giants
• The Differential Assembly History of the Centers and Outskirts of Main Sequence Galaxies at $z\sim 2.3$
• Gas Dynamics in the Central Molecular Zone and its connection with the Galactic Bar
• CO radial gradients in the bulge of M31
• Dynamical mirages: how bar-induced resonant trapping can mimic substructure clustering in dynamical parameter spaces
• Investigating Phosphorus Abundances in a Sample of APOGEE-2 Bulge Globular Clusters
• The multi-zone chemical evolution of the Galactic bulge: predicting abundances for different radial zones
• Globular clusters in \textsc{OrbIT}: complete dynamical characterisation of the globular cluster population of the Milky Way through updated orbital reconstruction
• Gas Transfer Between the Inner 3-kpc Disk and the Galactic Central Molecular Zone
• Turbulent Pressure Heats Gas and Suppresses Star Formation in Galactic Bar Molecular Clouds
• The Spheroidal Bulge of the Milky Way: Chemodynamically Distinct from the Inner-Thick Disc and Bar
• Predicting interstellar radiation fields from chemical evolution models
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data III. Panoramic view of the bulge
• Capivara: A Spectral-based Segmentation Method for IFU Data Cubes
• Towards Understanding the Milky Way's Typicality: Assessing the Chemodynamics of M31's Bulge & Bar, Thick & Thin Discs
• Quadrupole signature as a kinematic diagnostic to constrain bar properties : implications for the Milky Way
• The chemical and spatial variations of the bulge's velocity ellipsoids
• Dynamical properties of high-[Mg/Fe] stars in the Milky Way bar region
• The Two-infall Model Revisited: Constraints on Milky Way Bulge Assembly from >30,000 Galactic Chemical Evolution Models and Machine Learning
• Insights into the structure and kinematics of a Milky Way-like galaxy
• Age distribution of stars in boxy/peanut/X-shaped bulges formed without bar buckling
• Blanco DECam Bulge Survey (BDBS) IV: Metallicity Distributions and Bulge Structure from 2.6 Million Red Clump Stars