Determining the Local Dark Matter Density with SDSS G-dwarf data

Abstract

AbstractWe present a determination of the local dark matter density derived using the integrated Jeans equation method presented in Silverwoodet al.(2016) applied to SDSS-SEGUE G-dwarf data processed by Büdenbender et al. (2015). For our analysis we construct models for the tracer density, dark matter and baryon distribution, and tilt term (linking radial and vertical motions), and then calculate the vertical velocity dispersion using the integrated Jeans equation. These models are then fit to the data usingMultiNest, and a posterior distribution for the local dark matter density is derived. We find the most reliable determination to come from the α-young population presented in Büdenbenderet al.(2015), yielding a result of ρDM= 0.46+0.07−0.09GeV cm−3= 0.012+0.001−0.002M⊙pc−3. Our results also illuminate the path ahead for future analyses using Gaia DR2 data, highlighting which quantities will need to be determined and which assumptions could be relaxed.