Christian Moni Bidin: On the local dark matter density

“Weighting” the Galactic disk by means of the kinematics and spatial distribution of its stars is a classical method of measuring the gravitational mass enclosed in a given volume. Unfortunately, the huge information required for this measurements has so far limited all the investigations to a one-dimensional approximation within 1 kpc from the Galactic plane. Applying a fully three-dimensional formulation to three kinematical data sets from the literature, extending up to 4 kpc from the plane, we found a surprising lack of dark matter at the solar position, at variance with previous measurements and with the expectations of the most accepted dark matter halo models (Moni Bidin et al. 2012, ApJ, 751, 30). Bovy & Tremaine (2012, ApJ, 756, 89) later defied those results. In this talk, we will show that their criticism is not a viable explanation of our puzzling results, and show our ongoing studies, based on both synthetic data and an extended SDSS sample of more than 13000 stars, aimed to understand the origin of the unexpected lack of dark matter previously found.


Sala de Seminario Inst. Astronomia


Miercoles 16 de Octubre 2013