A neural network trained on simulations infers stripping times for Sagittarius stream stars from phase-space data, measuring a 0.3 dex/Gyr metallicity gradient and estimating ages for globular clusters such as Pal 12 and NGC 2419.
Co-formation of the Galactic disc and the stellar halo
6 Pith papers cite this work. Polarity classification is still indexing.
6
Pith papers citing it
abstract
Using a large sample of Main Sequence stars with 7-D measurements supplied by Gaia and SDSS, we study the kinematic properties of the local (within ~10 kpc from the Sun) stellar halo. We demonstrate that the halo's velocity ellipsoid evolves strongly with metallicity. At the low [Fe/H] end, the orbital anisotropy (the amount of motion in the radial direction compared to the tangential one) is mildly radial with 0.2<beta<0.4. However, for stars with [Fe/H]>-1.7 we measure extreme values of beta~0.9. Across the metallicity range considered, i.e. -3<[Fe/H]<-1, the stellar halo's spin is minimal, at the level of 20<v_theta (km/s) <30. Using a suite of cosmological zoom-in simulations of halo formation, we deduce that the observed acute anisotropy is inconsistent with the continuous accretion of dwarf satellites. Instead, we argue, the stellar debris in the inner halo were deposited in a major accretion event by a satellite with Mvir>10^10 Msun around the epoch of the Galactic disc formation, i.e. between 8 and 11 Gyr ago. The radical halo anisotropy is the result of the dramatic radialisation of the massive progenitor's orbit, amplified by the action of the growing disc.
representative citing papers
Hot Jupiter occurrence in the Galactic halo is low at ~0.13% with no significant difference between in-situ and accreted populations, well below disk rates.
A lithium chemical evolution model for the GSE galaxy matches survey data showing Spite-like and eRGB plateaus at low metallicity with a hint of reduced nova contributions.
ARTEMIS and EAGLE simulations classify L* galaxies by central BH-to-stellar-mass ratio and trace how merger history drives divergence in BH growth, star formation, and morphology, offering an explanation for the observed scatter and for MW/M31 differences.
Phase-space density is recovered from Gaia data for M4 and disrupted streams by correcting entropy injection and minimizing stream entropy, enabling original mass inference via Liouville's theorem.
High-precision abundances and Ba isotopic ratios in TYC 6044-714-1 favor an s+r nucleosynthesis scenario over i-process models, which require implausible conditions and mismatch isotopic data.
citing papers explorer
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Reconstructing the Stripping History of the Sagittarius Stream with Neural Networks
A neural network trained on simulations infers stripping times for Sagittarius stream stars from phase-space data, measuring a 0.3 dex/Gyr metallicity gradient and estimating ages for globular clusters such as Pal 12 and NGC 2419.
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Exoplanets in ancient stellar populations: occurrence constraints and hot-Jupiter candidates in the Galactic halo
Hot Jupiter occurrence in the Galactic halo is low at ~0.13% with no significant difference between in-situ and accreted populations, well below disk rates.
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Gaia-Sausage-Enceladus: Lithium evolution from early red-giant-branch and main-sequence stars
A lithium chemical evolution model for the GSE galaxy matches survey data showing Spite-like and eRGB plateaus at low metallicity with a hint of reduced nova contributions.
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Co-evolution of Supermassive Black Holes and their Host L* galaxies: implications for Milky Way and M31
ARTEMIS and EAGLE simulations classify L* galaxies by central BH-to-stellar-mass ratio and trace how merger history drives divergence in BH growth, star formation, and morphology, offering an explanation for the observed scatter and for MW/M31 differences.
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Applying Liouville's Theorem to Gaia Data
Phase-space density is recovered from Gaia data for M4 and disrupted streams by correcting entropy injection and minimizing stream entropy, enabling original mass inference via Liouville's theorem.
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Observational Signatures and Constraints on the Intermediate Neutron-Capture Process. The Case of the CEMP star TYC 6044-714-1 (RAVE J094921.8-161722)
High-precision abundances and Ba isotopic ratios in TYC 6044-714-1 favor an s+r nucleosynthesis scenario over i-process models, which require implausible conditions and mismatch isotopic data.