Compression on prior halos for failed galaxies. The rotation curve (left) of NGC 2903 and its DM halo density profiles (right). The green and blue lines are the gas and stellar disk contributions, respectively. The black dashed line is the ΛCDM predicted NFW halo assuming the abundance matching by Moster et al. (2013) and the halo mass–concentration relation by Dutton & Macciò (2014). The black solid line is the corresponding compressed halo. This example shows how a ΛCDM prior halo fit the data after baryonic effect is taken into account. The compressed halo shows significantly higher DM density at small radii.