Galaxy dynamics plays a fundamental role in understanding the formation and evolution of galaxies, as well as in constraining the nature of dark matter (DM). I will summarize recent results from the SPARC (Spitzer Photometry and Accurate Rotation Curves) project. To date, SPARC is the largest collection of disk galaxies (spirals and irregulars) with both HI rotation curves, probing the total gravitational potential, and near-IR surface photometry, probing the stellar mass distribution. I will discuss two classic methods to study the interplay between baryons and DM in galaxies: (1) fitting rotation curves with prescribed DM halos in a cosmological context, and (2) studying purely empirical scaling relations between kinematic and photometric quantities. I will show that the overall dynamics of disk galaxies is fully described by three basic laws: the baryonic Tully-Fisher relation for R-->infinity, the central density relation for R-->0, and the radial acceleration relation at each and every R. These empirical laws evince a tight connection between baryons and dynamics, even in DM-dominated low-mass galaxies, challenging LCDM models of galaxy formation.
Dr. Federico Lelli is a Research Associate at the University of Cardiff (UK). His main interests are the formation and evolution of galaxies, the nature of dark matter, and alternative theories of gravity. He completed his undergraduate studies at the University of Bologna (Italy) and obtained his Ph.D. degree from the University of Groningen (Netherlands). He has then worked at Case Western Reserve University (USA) and the European Southern Observatory (Germany). He has been recently appointed a permanent research position at INAF (Italy).