2018/04/10 by Casper Hesp, A. Helmi, Hesp, Casper +1
Physics and Astronomy · #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Scientific Research and Discoveries #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.1804.03670
openalex publication_date 2018/04/10 · openalex created_date 2022/09/30 · openalex updated_date 2026/07/28
It has recently been proposed that if the Galactic dark matter halo were\ntriaxial it would induce lumpiness in the velocity distribution of halo stars\nin the Solar Neighbourhood through orbital resonances. These substructures\ncould therefore provide a way of measuring its shape. We explore the robustness\nof this proposal by integrating numerically orbits starting from a realistic\nset of initial conditions in dark halo potentials of different shape. We have\nanalysed the resulting velocity distributions in Solar neighbourhood-like\nvolumes, and have performed statistical tests for the presence of kinematic\nsubstructures. Furthermore, we have characterized the particles' orbits using a\nFourier analysis. The local velocity distributions obtained are relatively\nsmooth, statistically consistent with being devoid of substructures even for a\ndark halo potential with significant but plausible triaxiality. Although\nresonances are indeed present and associated with specific regions of velocity\nspace, the fraction of stars associated to these is relatively minor. The most\nsignificant imprint of the triaxiality of the dark halo is in fact, a variation\nin the shape of the velocity ellipsoid with spatial location.\n