Galaxy dynamics in the MaNGA survey: Exploring sensitivity to background cosmology
ABSTRACT
KDESci Group Meeting (222nd)
Abstract: Galaxy dynamics covers a broad range of acceleration, extending across and below the background de Sitter scale of acceleration a_dS=cH, where c is the velocity of light and H is the Hubble parameter of the background cosmology. Asymptotic behavior in the outskirt of galaxies is marked by flat rotation curves, quantified by the baryonic Tully-Fisher relation. Here, we exploit Mapping Nearby Galaxies at APO (MaNGA) survey to study the transition to anomalous galaxy dynamics, away from the expected dynamics based on the observed light and Newton's theory of gravitation. Following a selection of a homogeneous sample of spiral galaxies from MaNGA, we present a binned stacked rotation curve in the normalized plot of the ratio of radial acceleration a_N/alpha of versus xi=a_N/a_dS, where alpha is inferred from line-of-sight velocities and a_N derives from the Newtonian gravitation potential based on the distribution of baryonic matter. We show a transition scale a_dS to anomalous dynamics at xi=1 in a 6-sigma departure form MUGS2 LCDM-galaxy models. This independently confirms the same previously observed in the Spitzer Photometric Accurate Rotation Curves (SPARC) catalog. We identify this coincidence with a finite sensitivity of inertial mass to background cosmology in weak gravitation below a_dS.
