The stellar halo in Local Group Hestia simulations III. Chemical abundance relations for accreted and in-situ stars

Abstract

Since the chemical abundances of stars are the fossil records of the physical conditions in galaxies, they provide the key information for recovering the assembly history of galaxies. In this work, we explore the chemo-chrono-kinematics of accreted and in-situ stars, by analyzing six M31/MW analogues from the HESTIA suite of cosmological hydrodynamics zoom-in simulations of the Local Group. We found that the merger debris are chemically distinct from the survived dwarf galaxies. The mergers debris have abundances expected for stars originating from dwarfs that had their star formation activity quenched at early times. Accreted stellar haloes, including individual debris, reveal abundance gradients in the ELz, where the most metal-rich stars have formed in the inner parts of the disrupted systems before the merger and mainly contribute to the central regions of the hosts. Therefore, we suggest that abundance measurements in the inner MW will allow constraining better the parameters of building blocks of the MW stellar halo. The MDFs of the individual debris show several peaks and the majority of debris have lower metallicity than the in-situ stars for Lz>0, while non-rotating and retrograde accreted stars are similar to the in-situ. Prograde accreted stars show a prominent knee in the [Fe/H]-[Mg/Fe] plane while the retrograde stars typically deposit to a high-[Mg/Fe] sequence. We found that the metal-poor stars ([Fe/H]<-1) of the HESTIA galaxies exhibit between zero to 80 km/s net rotation which is consistent with the Aurora population. At higher metallicities, we detect a sharp transition (spin-up) from the turbulent phase to a disk-like rotation. Mergers debris are similar in the [Fe/H]-[Mg/Fe] plane. However, combining a set of abundances allows to capture chemical patterns corresponding to different debris, which are the most prominent as a function of stellar age.

Paper III in series of III, 21 pages, 17 figures, A&A in press

References in corpus (53)

• The NumPy array: a structure for efficient numerical computation
• The GALAH Survey: Scientific Motivation
• Evidence for Two Early Accretion Events That Built the Milky Way Stellar Halo
• Dark matter and cosmic structure
• Streams, substructures and the early history of the Milky Way
• Evidence from the H3 Survey that the Stellar Halo is Entirely Comprised of Substructure
• Kraken reveals itself -- the merger history of the Milky Way reconstructed with the E-MOSAICS simulations
• The Galaxy and its stellar halo: insights on their formation from a hybrid cosmological approach
• From dawn till disk: Milky Way's turbulent youth revealed by the APOGEE+Gaia data
• VINTERGATAN I: The origins of chemically, kinematically and structurally distinct discs in a simulated Milky Way-mass galaxy
• The Global Dynamical Atlas of the Milky Way mergers: Constraints from Gaia EDR3 based orbits of globular clusters, stellar streams and satellite galaxies
• Reverse engineering the Milky Way
• The Sixth Data Release of the Radial Velocity Experiment (RAVE) -- I: Survey Description, Spectra and Radial Velocities
• Infall of substructures onto a Milky Way-like dark halo
• The total stellar halo mass of the Milky Way
• The chemical characterisation of halo substructure in the Milky Way based on APOGEE
• Discovery of a New, Polar-Orbiting Debris Stream in the Milky Way Stellar Halo
• Investigating the Andromeda Stream: III. A Young Shell System in M31
• The Fall of a Giant. Chemical evolution of Enceladus, alias the Gaia Sausage
• Origin of chemically distinct discs in the Auriga cosmological simulations
• The Hestia project: simulations of the Local Group
• A box full of chocolates: The rich structure of the nearby stellar halo revealed by Gaia and RAVE
• The Milky Way bar and bulge revealed by APOGEE DR16 and Gaia EDR3
• All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud
• The fine-grained phase-space structure of Cold Dark Matter halos
• The imprint of clump formation at high redshift. I. A disc alpha-abundance dichotomy
• Origin of the excess of high-energy retrograde stars in the Galactic halo
• Selecting accreted populations: metallicity, elemental abundances, and ages of the Gaia-Sausage-Enceladus and Sequoia populations
• Detection of the LMC-induced sloshing of the Galactic halo
• galstreams: A Library of Milky Way Stellar Stream Footprints and Tracks
• The PAndAS Field of Streams: stellar structures in the Milky Way halo toward Andromeda and Triangulum
• The GALAH Survey: Chemical tagging and chrono-chemodynamics of accreted halo stars with GALAH+ DR3 and $Gaia$ eDR3
• APOGEE Chemical Abundances of the Sagittarius Dwarf Galaxy
• A tale of two populations: surviving and destroyed dwarf galaxies and the build up of the Milky Way's stellar halo
• GASTRO library I: the simulated chemodynamical properties of several GSE-like stellar halos
• Broken into Pieces: ATLAS and Aliqa Uma as One Single Stream
• A massive mess: When a large dwarf and a Milky Way-like galaxy merge
• Bimodality of [α/Fe]-[Fe/H] distributions is a natural outcome of dissipative collapse and disc growth in Milky Way-type galaxies
• VINTERGATAN III: how to reset the metallicity of the Milky Way
• The Pristine Inner Galaxy Survey (PIGS) II: Uncovering the most metal-poor populations in the inner Milky Way
• The effects of dynamical substructure on Milky Way mass estimates from the high velocity tail of the local stellar halo
• The Galaxy Progenitors of Stellar Streams around Milky Way-mass Galaxies in the FIRE Cosmological Simulations
• The distribution of globular clusters in kinematic spaces does not trace the accretion history of the host galaxy
• The challenge of simultaneously matching the observed diversity of chemical abundance patterns in cosmological hydrodynamical simulations
• The detailed chemical abundance patterns of accreted halo stars from the optical to infrared
• Evidence for sub-Chandrasekhar Type Ia supernovae from the last major merger
• The central spheroids of Milky Way mass-sized galaxies
• Reading the CARDs: the Imprint of Accretion History in the Chemical Abundances of the Milky Way's Stellar Halo
• The stellar halo in Local Group Hestia simulations I. The in-situ component and the effect of mergers
• The stellar halo in Local Group Hestia simulations II. The accreted component
• Explaining the chemical trajectories of accreted and in-situ halo stars of the Milky Way
• Anisotropic satellite accretion onto the Local Group with HESTIA
• Modelling the chemical evolution of the Milky Way

Cited by in corpus (12)

• The Three-Phase Evolution of the Milky Way
• Formation of Galactic Disks I: Why Did the Milky Way's Disk Form Unusually Early?
• Metallicity distributions of halo stars: do they trace the Galactic accretion history?
• The stellar halo in Local Group Hestia simulations II. The accreted component
• Observational Constraints of Radial Migration in the Galactic Disc Driven by the Slowing Bar
• Evolution of the radial ISM metallicity gradient in the Milky Way disk since redshift $\approx 3$
• Formation of Transitional cE/UCD Galaxies through Massive/Dwarf Disc Galaxy Mergers
• How well can we unravel the accreted constituents of the Milky Way stellar halo? A test on cosmological hydrodynamical simulations
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data I. Method validation
• The Nephele ecosystem: stars, globular clusters, and stellar streams associated with the progenitor galaxy of $\omega$ Centauri
• HR-GO II: chemical abundances of low-$E$ retrograde dynamically-tagged-groups: Revealing Thamnos as a very metal-poor substructure
• The chemodynamical memory of a major merger in a NIHAO-UHD Milky Way analogue -- I. A golden thread through time and space