Dark Matter Phase Transition Constrained at O(0.1)eV with LSB Rotation Curves

Abstract

c . We test this model by fitting rotation curves from Low Surface Brightness (LSB) galaxies from The HI Nearby Galaxy Survey (THINGS). We use a particular DM cored profile that contains three parameters: a typical scale length (rs) and density (r0) of the halo and a core radius (rc) stemming from the relativistic nature of the BDM model. Since the energy Ec parameterizes the phase transition due to the underlying particle physics model, it is independent on the details of galaxy and/or structure formation and therefore the DM profile parameters rs,rc,Ec are constrained, leaving only two free parameters. Through the results we agree with previous ones implying that cored profiles are preferred over the N-body motivated cuspy profiles. We also compute 2D likelihoods of the BDM parameters rc and Ec for the different galaxies and matter contents, and find an average galaxy core radius rc = 1.48 kpc and a transition energy between hot and cold dark matter at Ec =0.06 +0.07 −0.03 eV. The phase transition scale Ec is a new fundamental