The local dark matter density from SDSS-SEGUE G-dwarfs

Abstract

We derive the local dark matter density by applying the integrated Jeans equation method from Silverwood et al. to SDSS-SEGUE G-dwarf data processed and presented by Büdenbender et al. We use the MULTINEST Bayesian nested sampling software to fit a model for the baryon distribution, dark matter, and tracer stars, including a model for the 'tilt term' that couples the vertical and radial motions, to the data. The α-young population from Büdenbender et al. yields the most reliable result of ρdm = 0.46-0.08+0.07 GeV cm-3 = 0.012-0.002+0.002 M⊙ pc-3. Our analyses yield inconsistent results for the α-young and α-old data, pointing to problems in the tilt term and its modelling, the data itself, the assumption of a flat rotation curve, or the effects of disequilibria.