High-resolution dark matter density profiles of THINGS dwarf galaxies: Correcting for non-circular motions

Understand

We present a new method to remove the impact of random and small-scale non-circular motions from HI velocity fields in galaxies in order to better constrain the dark matter properties for these objects.

• This method extracts the circularly rotating velocity components from the HI data cube and condenses them into a so-called bulk velocity field.
• We derive high-resolution rotation curves of IC 2574 and NGC 2366 based on bulk velocity fields derived from The HI Nearby Galaxy Survey (THINGS) obtained at the VLA.
• The bulk velocity field rotation curves are significantly less affected by non-circular motions and constrain the dark matter distribution in our galaxies, allowing us to address the discrepancy between the inferred and predicted dark matter distribution in galaxies (the "cusp/core" problem).