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 hidden giant: discovery of an enormous Galactic dwarf satellite in Gaia DR2
4 Pith papers cite this work. Polarity classification is still indexing.
4
Pith papers citing it
abstract
We report the discovery of a Milky Way satellite in the constellation of Antlia. The Antlia 2 dwarf galaxy is located behind the Galactic disc at a latitude of $b\sim 11^{\circ}$ and spans $1.26$ degrees, which corresponds to $\sim2.9$ kpc at its distance of 130 kpc. While similar in spatial extent to the Large Magellanic Cloud, Antlia 2 is orders of magnitude fainter at $M_V=-9$ mag, making it by far the lowest surface brightness system known (at $\sim31.9$ mag/arcsec$^2$), $\sim100$ times more diffuse than the so-called ultra diffuse galaxies. The satellite was identified using a combination of astrometry, photometry and variability data from \textit{Gaia} Data Release 2, and its nature confirmed with deep archival DECam imaging, which revealed a conspicuous BHB signal. We have also obtained follow-up spectroscopy using AAOmega on the AAT, identifying 159 member stars, and we used them to measure the dwarf's systemic velocity, $290.9\pm0.5$km/s, its velocity dispersion, $5.7\pm1.1$ km/s, and mean metallicity, [Fe/H]$=-1.4$. From these properties we conclude that Antlia 2 inhabits one of the least dense Dark Matter (DM) halos probed to date. Dynamical modelling and tidal-disruption simulations suggest that a combination of a cored DM profile and strong tidal stripping may explain the observed properties of this satellite. The origin of this core may be consistent with aggressive feedback, or may even require alternatives to cold dark matter (such as ultra-light bosons).
citation-role summary
background 1
citation-polarity summary
fields
astro-ph.GA 4years
2026 4verdicts
UNVERDICTED 4roles
background 1polarities
background 1representative citing papers
Spectroscopic measurements confirm a tight 6D phase-space clump of four RGB stars as part of the distant southern spur of the Sagittarius stream, likely stripped from Sagittarius's halo in the earliest interaction phases.
New hydrodynamical simulations show that dwarf galaxy stellar mass-halo mass relations and star formation histories are more influenced by host halo concentration than by the 5 cMpc scale environment.
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
-
Columba: isolated dwarf galaxy populations in diverse cosmological environments simulated with a cold interstellar medium
New hydrodynamical simulations show that dwarf galaxy stellar mass-halo mass relations and star formation histories are more influenced by host halo concentration than by the 5 cMpc scale environment.