The EMBLA Survey -- Metal-poor stars in the Galactic bulge

Abstract

Cosmological models predict the oldest stars in the Galaxy should be found closest to the centre of the potential well, in the bulge. The EMBLA Survey successfully searched for these old, metal-poor stars by making use of the distinctive SkyMapper photometric filters to discover candidate metal-poor stars in the bulge. Their metal-poor nature was then confirmed using the AAOmega spectrograph on the AAT. Here we present an abundance analysis of 10 bulge stars with -2.8<[Fe/H]<-1.7 from MIKE/Magellan observations, in total determining the abundances of 22 elements. Combining these results with our previous high-resolution data taken as part of the Gaia-ESO Survey, we have started to put together a picture of the chemical and kinematic nature of the most metal-poor stars in the bulge. The currently available kinematic data is consistent with the stars belonging to the bulge, although more accurate measurements are needed to constrain the stars' orbits. The chemistry of these bulge stars deviates from that found in halo stars of the same metallicity. Two notable differences are the absence of carbon-enhanced metal-poor bulge stars, and the alpha-element abundances exhibit a large intrinsic scatter and include stars which are underabundant in these typically enhanced elements.

arXiv comment20 pages, 16 figures. Accepted to Monthly Notices of the Royal Astronomical Society. Online tables can be found at http://www.astro.lu.se/~louise/data

References in corpus (100)

• The chemical composition of the Sun
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The Dartmouth Stellar Evolution Database
• First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy
• VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
• The First Stars
• Optimal Techniques in Two-dimensional Spectroscopy: Background Subtraction for the 21st Century
• Galactic Evolution of Sr, Y, Zr: A Multiplicity of Nucleosynthetic Processes
• Reddening and Extinction Toward the Galactic Bulge from OGLE-III: The Inner Milky Way's Rv ~ 2.5 Extinction Curve
• Nucleosynthetic signatures of the first stars
• SkyMapper and the Southern Sky Survey
• Near-Field Cosmology with Metal-Poor Stars
• A stellar relic from the early Milky Way
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. V. Evidence for a wide age distribution and a complex MDF
• A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-Poor Stars
• The Milky Way's circular velocity curve between 4 and 14 kpc from APOGEE data
• Mapping the Three-Dimensional Density of the Galactic Bulge with VVV Red Clump Stars
• The Formation and Fragmentation of Disks around Primordial Protostars
• Non-LTE calculations for neutral Na in late-type stars using improved atomic data
• A single low-energy, iron-poor supernova as the source of metals in the star SMSS J 031300.36-670839.3
• Our Milky Way as a Pure-Disk Galaxy -- A Challenge for Galaxy Formation
• Detailed Abundances for 28 Metal-poor Stars: Stellar Relics in the Milky Way
• NLTE line formation of Fe for late-type stars. I. Standard stars with 1D and <3D> model atmospheres
• NLTE line formation of Fe in late-type stars II: 1D spectroscopic stellar parameters
• The Metal Content of Bulge Field Stars from FLAMES-GIRAFFE Spectra. I. Stellar parameters and Iron Abundances
• Formation of the First Stars
• The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] < -3.5
• On the Initial Mass Function of Population III Stars
• An extremely primitive halo star
• First Stars VIII -- Enrichment of the neutron-capture elements in the early Galaxy
• Carbon-Enhanced Metal-Poor Star Frequencies in the Galaxy: Corrections for the Effect of Evolutionary Status on Carbon Abundances
• ARGOS III: Stellar Populations in the Galactic Bulge of the Milky Way
• Gaia FGK Benchmark Stars - Metallicity
• Gaia FGK Benchmark Stars: Effective temperatures and surface gravities
• CH in stellar atmospheres: an extensive linelist
• Stellar populations in the Milky Way bulge region : Towards solving the Galactic bulge and bar shapes using 2MASS data
• HE 0557-4840 - Ultra-Metal-Poor and Carbon-Rich
• Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars
• Chemical similarities between Galactic bulge and local thick disk red giants: O, Na, Mg, Al, Si, Ca and Ti
• Probing the Formation of the First Low-Mass Stars with Stellar Archaeology
• The Most Metal-Poor Stars. IV. The Two Populations With [Fe/H] < -3.0
• Performance of AAOmega: the AAT multi-purpose fibre-fed spectrograph
• The Frequency of Carbon-Enhanced Metal-Poor Stars in the Galaxy from the HERES sample
• ARGOS IV: The Kinematics of the Milky Way Bulge
• Both accurate and precise gf-values for FeII lines
• Chemical Evolution in Hierarchical Models of Cosmic Structure II: The Formation of the Milky Way Stellar Halo and the Distribution of the Oldest Stars
• Accurate fundamental parameters for Lower Main Sequence Stars
• Chromium: NLTE abundances in metal-poor stars and nucleosynthesis in the Galaxy
• The Ubiquity of the Rapid Neutron-Capture Process
• Pre-galactic metal enrichment - The chemical signatures of the first stars
• Improved Laboratory Transition Probabilities for Neutral Chromium and Re-determination of the Chromium Abundance for the Sun and Three Stars
• Linking dwarf galaxies to halo building blocks with the most metal-poor star in Sculptor
• HE 1327-2326, an unevolved star with [Fe/H]<-5.0. II. New 3D-1D corrected abundances from a VLT/UVES spectrum
• Extremely metal-poor stars in classical dwarf spheroidal galaxies: Fornax, Sculptor and Sextans
• Detailed analysis of Balmer lines in cool dwarf stars
• NLTE determination of the aluminium abundance in a homogeneous sample of extremely metal-poor stars
• Improved Ti II log(gf) Values and Abundance Determinations in the Photospheres of the Metal-Poor Star HD 84937
• ARGOS II: The Galactic Bulge Survey
• The AMBRE project: A new synthetic grid of high-resolution FGKM stellar spectra
• The stellar content of the Hamburg/ESO survey. V. The metallicity distribution function of the Galactic halo
• Atomic and Molecular Data for Optical Stellar Spectroscopy
• High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the SkyMapper Survey
• Deriving Stellar Effective Temperatures of Metal-Poor Stars with the Excitation Potential Method
• Reddening and metallicity maps of the Milky Way Bulge from VVV and 2MASS. I.The method and minor axis maps
• The broadening of Fe II lines by neutral hydrogen collisions
• The s-process in the Galactic halo: the fifth signature of spinstars in the early Universe?
• Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way
• Fe I Oscillator Strengths for the Gaia-ESO Survey
• Reddening and metallicity maps of the Milky Way bulge from VVV and 2MASS III. The first global photometric metallicity map of the Galactic bulge
• The Best and Brightest Metal-Poor Stars
• Improved Ni I log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
• The extremely low-metallicity tail of the Sculptor dwarf spheroidal galaxy
• SkyMapper Filter Set: Design and Fabrication of Large Scale Optical Filters
• Explaining the Ba, Y, Sr, and Eu abundance scatter in metal-poor halo stars: constraints to the r-process
• The Gaia-ESO Survey: processing of the FLAMES-UVES spectra
• Fe I Oscillator Strengths for Transitions from High-lying Even-Parity Levels
• Faint Population III supernovae as the origin of the most iron-poor stars
• Spectroscopic analysis of metal-poor stars from LAMOST: early results
• The Most Metal-Poor Stars. I. Discovery, Data, and Atmospheric Parameters
• Mining the Galactic Halo for Very Metal-Poor Stars
• The Gaia-ESO Survey: the most metal-poor stars in the Galactic bulge
• On the Abundance of Potassium in Metal-Poor Stars
• The formation of the extremely primitive star SDSS J102915+172927 relies on dust
• High-resolution abundance analysis of red giants in the globular cluster NGC 6522
• The Spatial Distribution of the Galactic First Stars II: SPH Approach
• Young stars in an old bulge: a natural outcome of internal evolution in the Milky Way
• Very Metal-poor Stars in the Outer Galactic Bulge Found by the Apogee Survey
• On the formation of very metal-poor stars: The case of SDSS J1029151+172927
• Chemistry of the Most Metal-poor Stars in the Bulge and the z > 10 Universe
• Where are the First Stars now?
• The X-Shaped Milky Way Bulge in OGLE-III Photometry and in N-Body Models
• The infrared colors of the Sun
• X-Shooter GTO: Chemical analysis of a sample of EMP candidates
• Finding the Most Metal-poor Stars of the Galactic Halo with the Hamburg/ESO Objective-Prism Survey
• The low Sr/Ba ratio on some extremely metal-poor stars
• A high-velocity bulge RR Lyrae variable on a halo-like orbit
• Sick, the spectroscopic inference crank
• The chromosphere and prominence magnetometer

Cited by in corpus (81)

• Chemodynamical history of the Galactic Bulge
• Atomic data for the Gaia-ESO Survey
• Where are the most ancient stars in the Milky Way?
• JINAbase: A database for chemical abundances of metal-poor stars
• The solar silicon abundance based on 3D non-LTE calculations
• The oldest and most metal poor stars in the APOSTLE Local Group simulations
• Kinematics of Highly R-Process-Enhanced Field Stars: Evidence for an Accretion Origin and Detection of Several Groups from Disrupted Satellites
• The SkyMapper DR1.1 Search for Extremely Metal-Poor Stars
• From actinides to zinc: Using the full abundance pattern of the brightest star in Reticulum II to distinguish between different r-process sites
• The Pristine survey III: Spectroscopic confirmation of an efficient search for extremely metal-poor stars
• Pristine IX: CFHT ESPaDOnS Spectroscopic Analysis of 115 Bright Metal-Poor Candidate Stars
• The lanthanide fraction distribution in metal-poor stars: a test of neutron star mergers as the dominant r-process site
• The Bulge Radial Velocity Assay for RR Lyrae stars (BRAVA-RR) DR2: a Bimodal Bulge?
• SkyMapper stellar parameters for Galactic Archaeology on a grand-scale
• Grids of stellar models with rotation: V. Models from 1.7 to 120 Msun at zero metallicity
• The Pristine Inner Galaxy Survey (PIGS) II: Uncovering the most metal-poor populations in the inner Milky Way
• The R-Process Alliance: Chemo-Dynamically Tagged Groups of Halo $r$-Process-Enhanced Stars Reveal a Shared Chemical-Evolution History
• Two Groups of Red Giants with Distinct Chemical Abundances in the Bulge Globular Cluster NGC 6553 Through the Eyes of APOGEE
• The r-Process Pattern of a Bright, Highly r-Process-Enhanced, Metal-Poor Halo Star at [Fe/H] ~ -2
• The COMBS Survey -- II. Distinguishing the Metal-Poor Bulge from the Halo Interlopers
• Evidence for the accretion origin of halo stars with an extreme r-process enhancement
• On the inconsistency of [C/Fe] abundances and the fractions of carbon-enhanced metal-poor stars among various stellar surveys
• The Pristine survey -- XII: Gemini-GRACES chemo-dynamical study of newly discovered extremely metal-poor stars in the Galaxy
• High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1
• CAPOS: The bulge Cluster APOgee Survey I. Overview and initial ASPCAP results
• The COMBS survey I: Chemical Origins of Metal-Poor Stars in the Galactic Bulge
• High-resolution abundance analysis of four red giants in the globular cluster NGC 6558
• Iron-peak elements Sc, V, Mn, Cu and Zn in Galactic bulge globular clusters
• The Pristine Inner Galaxy Survey (PIGS) III: carbon-enhanced metal-poor stars in the bulge
• The Pristine Inner Galaxy Survey (PIGS) V: a chemo-dynamical investigation of the early assembly of the Milky Way with the most metal-poor stars in the bulge
• Evidence against anomalous compositions for giants in the Galactic Nuclear Star Cluster
• Stars behind bars II: A cosmological formation scenario for the Milky Way's central stellar structure
• Oxygen and zinc abundances in 417 Galactic bulge red giants
• Carbon-Enhanced Metal-Poor star candidates from BP/RP Spectra in $Gaia$ DR3
• The R-Process Alliance: Chemo-Dynamically Tagged Groups II. An Extended Sample of Halo $r$-Process-Enhanced Stars
• A bound on the 12C/13C ratio in near-pristine gas with ESPRESSO
• Unusual neutron-capture nucleosynthesis in a carbon-rich Galactic bulge star
• Using the Multi-Object Adaptive Optics demonstrator RAVEN to observe metal-poor stars in and towards the Galactic Centre
• The most metal-poor Galactic globular cluster: the first spectroscopic observations of ESO280-SC06
• The energy distribution of the first supernovae
• Chemical enrichment of stars due to accretion from ISM during the Galaxy's assembly
• Modelling the chemical enrichment of Population III supernovae: The origin of the metals in near-pristine gas clouds
• Exploring the diversity and similarity of radially anisotropic Milky Way-like stellar haloes: implications for disrupted dwarf galaxy searches
• HERBS I: Metallicity and alpha enhancement along the Galactic bulge minor axis
• The Most Metal-poor Stars in the Inner Bulge
• Abundance analysis of APOGEE spectra for 58 metal-poor stars from the bulge spheroid
• Another relic bulge globular cluster: ESO 456-SC38 (Djorgovski~2)
• Decoding the compositions of four bright $r$-process-enhanced stars
• Fates of the oldest intermediate-mass stars - Primordial to Extremely Metal-Poor AGB and Super-AGB Stars: White Dwarf or Supernova progenitors
• Keck HIRES Spectroscopy of SkyMapper Commissioning Survey Candidate Extremely Metal-Poor Stars
• HERBS II: Detailed chemical compositions of Galactic bulge stars
• The stochastic enrichment of Population II stars
• Discovery of 18 stars with -3.10 < [Fe/H] < -1.45 in the Sagittarius dwarf galaxy
• Spectroscopic study of the elusive globular cluster ESO452-SC11 and its surroundings
• The Pristine Inner Galaxy Survey (PIGS) VII: a discovery of the first inner Galaxy CEMP-r/s star
• The retrograde orbit of the globular cluster FSR1758 revealed with Gaia DR2
• On the likelihoods of finding very metal-poor (and old) stars in the Milky Way's disc, bulge, and halo
• High-speed stars. II. An unbound star, young stars, bulge metal-poor stars, and Aurora candidates
• On the dearth of C-enhanced metal-poor stars in the Galactic bulge
• Towards ultra metal-poor DLAs: linking the chemistry of the most metal-poor DLA to the first stars
• The Occurrence and Impact of Carbon-Oxygen Shell Mergers in Massive Stars
• Finding $r$-II sibling stars in the Milky Way with the Greedy Optimistic Clustering algorithm
• The Pristine Inner Galaxy Survey (PIGS) X. Probing the early chemical evolution of the Sagittarius dwarf galaxy with carbon abundances
• Impact of distance determinations on Galactic structure. II. Old tracers
• The Pristine survey -- XX: GTC follow-up observations of extremely metal-poor stars identified from Pristine and LAMOST
• Could very low-metallicity stars with rotation-dominated orbits have been shepherded by the bar?
• The S-PLUS Ultra-Short Survey: first data release
• Untangling the Sources of Abundance Dispersion in Low-Metallicity Stars
• Radial velocities of RR Lyrae stars in and around NGC 6441
• Discovery of an Extremely r-process-enhanced Thin-disk Star with [Eu/H] = +0.78
• CAPOS: The bulge Cluster APOgee Survey VIII. Final ASPCAP results for all clusters
• The first r-process enhanced star confirmed to be a member of the Galactic bulge
• Very metal-poor stars in the solar vicinity: kinematics and abundance analysis
• On the Chemical Composition of the Evolved Very Bright Metal-Poor Star HD 1936
• Detailed Abundance Determination of Metal-Poor Stars with X-Shooter I. Unusual Chemistry in Halo Stars
• The DORCHA suite: nature, nurture, and the phase space distribution of the Milky Way's high redshift progenitors today
• Blanco DECam Bulge Survey (BDBS) IV: Metallicity Distributions and Bulge Structure from 2.6 Million Red Clump Stars
• The COMBS Survey -- III. The Chemodynamical Origins of Metal-Poor Bulge Stars
• UVES analysis of red giants in the bulge globular cluster NGC 6522
• An ancient system hidden in the Galactic plane?
• The R-Process Alliance: A Nearly Complete R-Process Abundance Template Derived from Ultraviolet Spectroscopy of the R-Process-Enhanced Metal-Poor Star HD 222925