Raising galaxy rotation curves via dressing

We present a manifestly diffeomorphism-invariant simple model of galaxy dynamics obtained by applying the dressing field method (DFM) to a general relativistic system comprising the metric and four scalar fields, phenomenologically representing the four-velocity of a cosmological fluid or dust field. The DFM, a systematic tool for extracting the gauge-invariant content in general relativistic theories, provides a physical coordinatization that yields corrective terms to the rotational velocity profile. These corrections produce galaxy rotation curves that combine Keplerian and constant velocity terms, effectively emulating a dark matter contribution. We compareDFM-derived rotation curves to observed data for spiral galaxies, from the Spitzer Photometry and Accurate Rotation Curves database, showing that the DFM allows one to fit them well.