2024/05/28 by R. G. Carlberg, Carlberg, Raymond G., Adrian Jenkins +5
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2405.18522
openalex publication_date 2024/05/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The dark matter subhalos orbiting in a galactic halo perturb the orbits of stars in thin stellar streams. Over time the random velocities in the streams develop non-Gaussian wings. The rate of velocity increase is approximately a random walk at a rate proportional to the number of subhalos, primarily those in the mass range ≈ 106-7 M_\odot. The distribution of random velocities in long, thin, streams is measured in simulated Milky Way-like halos that develop in representative WDM and CDM cosmologies. The radial velocity distributions are well modeled as the sum of a Gaussian and an exponential. The resulting MCMC fits find Gaussian cores of 1-2 km/sec and exponential wings that increase from 3 km/sec for 5.5 keV WDM, 4 km/sec for 7 keV WDM, to 6 km/sec for a CDM halo. The observational prospects to use stream measurements to constrain the nature of galactic dark matter are discussed.