GraphNPE recovers a significantly lower central density for Boötes I consistent with a core while Draco remains marginally cuspy, and demonstrates that higher-order velocity moments reduce bias in dynamical modeling.
The Quenching of the Ultra-Faint Dwarf Galaxies in the Reionization Era
4 Pith papers cite this work. Polarity classification is still indexing.
abstract
We present new constraints on the star formation histories of six ultra-faint dwarf galaxies: Bootes I, Canes Venatici II, Coma Berenices, Hercules, Leo IV, and Ursa Major I. Our analysis employs a combination of high-precision photometry obtained with the Advanced Camera for Surveys on the Hubble Space Telescope, medium-resolution spectroscopy obtained with the DEep Imaging Multi-Object Spectrograph on the W.M. Keck Observatory, and updated Victoria-Regina isochrones tailored to the abundance patterns appropriate for these galaxies. The data for five of these Milky Way satellites are best fit by a star formation history where at least 75% of the stars formed by z~10 (13.3 Gyr ago). All of the galaxies are consistent with 80% of the stars forming by z~6 (12.8 Gyr ago) and 100% of the stars forming by z~3 (11.6 Gyr ago). The similarly ancient populations of these galaxies support the hypothesis that star formation in the smallest dark matter sub-halos was suppressed by a global outside influence, such as the reionization of the universe.
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astro-ph.GA 4years
2026 4verdicts
UNVERDICTED 4representative citing papers
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.
Photometric analysis yields metallicity distributions for 3917 stars across 12 faint Milky Way satellites, showing average [Fe/H] ~ -2.3 dex, 170 EMP candidates, and no gradients in ultra-faint systems.
Five of seven modeled M31 dwarf spheroidals show anomalously low central DM densities at 150 pc, with star formation heating disfavored as the sole cause.
citing papers explorer
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Dark Matter in Draco and Bo\"otes I: Hints of a Core in an Ultra-Faint Dwarf from Simulation-Based Inference
GraphNPE recovers a significantly lower central density for Boötes I consistent with a core while Draco remains marginally cuspy, and demonstrates that higher-order velocity moments reduce bias in dynamical modeling.
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The Hubble Missing Globular Clusters Survey IV. Ultra-faint compact satellites of the Milky Way. The case of Koposov 2
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.
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The Pristine Dwarf Galaxy Survey -- VII. The metallicity distributions of 12 Milky Way faint satellites
Photometric analysis yields metallicity distributions for 3917 stars across 12 faint Milky Way satellites, showing average [Fe/H] ~ -2.3 dex, 170 EMP candidates, and no gradients in ultra-faint systems.
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It's Not Just Star Formation: A trend of low dark matter densities in the Andromeda dwarf galaxy system
Five of seven modeled M31 dwarf spheroidals show anomalously low central DM densities at 150 pc, with star formation heating disfavored as the sole cause.