Probing Hidden Galaxies: Tracing Dark Matter with the GD-1 Stellar Stream
Jacob Nibauer and collaborators analyzed the GD-1 stellar stream’s star motions to study invisible dark matter subhalos around the Milky Way. They found that the stream’s velocity dispersion is higher than expected, suggesting interactions with compact, dense dark matter clumps. Their models show that about 5% of the Milky Way’s mass is in these subhalos, possibly indicating self-interacting dark matter rather than the standard cold dark matter model.
A Pulsar Clue: Finding a Hidden Clump of Dark Matter Near the Sun
Chakrabarti et al. report the first detection of a dark matter sub-halo near the Sun using pulsar timing data. By analyzing excess acceleration in binary pulsars, they infer a compact dark object with a mass around 10 million solar masses. This finding supports ΛCDM predictions and opens a new method for probing dark matter in our Galaxy.
Unearthing the Dark Side: What Three Tiny Galaxies Reveal About Dark Matter
Hao Yang and colleagues studied the dark matter in three Milky Way dwarf galaxies using DESI data. They compared single- and two-population models, finding diverse inner dark matter profiles: Draco showed a cusp-like center, while Sextans and Ursa Minor leaned toward cores. Their results align with previous findings but also highlight uncertainties from data and modeling choices.
Broken Expectations: How Modeling Assumptions Impact Our View of Dark Matter in Dwarf Galaxies
This study shows that common methods used to model dark matter in dwarf galaxies, like the Jeans equation, can underestimate central densities and J-factors due to simplifying assumptions. Using realistic simulations, the authors find that tidal forces and orbital dynamics can bias results, suggesting that more accurate modeling is needed for interpreting dark matter signals.