The localdark 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 Bdenbender 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 -young population from Bdenbender et al. yields the most reliable result of dm = 0.46 +0.07 -0.08 GeV cm -3 = 0.012 +0.002 -0.002 M pc -3 . Our analyses yield inconsistent results for the -young and -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.