One acceleration measurement equals ~10^5 phase-space measurements for local dark matter density estimation, with acceleration outperforming Jeans modeling in both equilibrium and perturbed Milky Way simulations.
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Co-formation of the Galactic disc and the stellar halo
12 Pith papers cite this work. Polarity classification is still indexing.
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.
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UNVERDICTED 12representative citing papers
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.
AuriGLOBES is a new subgrid model implemented in Auriga simulations that incorporates compressive tides and compact-object mass loss to transform an initial Schechter mass function into observed globular cluster populations while reproducing the GC system mass-halo mass relation.
Galaxy size at fixed stellar mass encodes the link between long-term gas inflow histories, current inner gas reservoirs, and metallicity via differences in assembly timing.
Koposov 2 is shown to be an old (13.7 Gyr) star cluster with half-light radius 2.7 pc, absolute magnitude -0.95, and stellar mass 372 solar masses, supporting a star cluster classification over a dwarf galaxy.
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.
N-body simulations of the Milky Way-GSE merger indicate that halo and merger-formed globular clusters largely retain orbital energy, allowing most GSE-linked GCs to trace accretion events in the E-Lz plane.
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.
Resolved stellar property gradients in Milky Way analog progenitors show inside-out assembly with minor, temporary disruption from major mergers.
High-precision analysis of TYC 6044-714-1 favors s+r nucleosynthesis over i-process models, which require implausible conditions and mismatch Ba isotopes.
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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 analysis of TYC 6044-714-1 favors s+r nucleosynthesis over i-process models, which require implausible conditions and mismatch Ba isotopes.