16 research outputs found
Core-Cusp revisited and Dark Matter Phase Transition Constrained at O(0.1) eV with LSB Rotation Curve
Recently a new particle physics model called Bound Dark Matter (BDM) has been
proposed in which dark matter (DM) particles are massless above a threshold
energy (Ec) and acquire mass below it due to nonperturbative methods.
Therefore, the BDM model describes DM particles which are relativistic, hot
dark matter, in the inner regions of galaxies and describes nonrelativistic,
cold dark matter, where halo density is below rho_c = Ec^4. To realize this
idea in galaxies we use a particular DM cored profile that contains three
parameters: a scale length (rs) and density (rho_0) of the halo, and a core
radius (rc) stemming from the relativistic nature of the BDM model. We test
this model by fitting rotation curves of seventeen Low Surface Brightness
galaxies from The HI Nearby Galaxy Survey (THINGS). Since the energy Ec
parameterizes the phase transition due to the underlying particle physics
model, it is independent on the details of galaxy or structure formation and
therefore the DM profile parameters rs, rc, Ec are constrained, leaving only
two free parameters. The high spatial and velocity resolution of this sample
allows to derive the model parameters through the numerical implementation of
the chi^2-goodness-of-fit test to the mass models. We compare the fittings with
those of Navarro-Frenk-White (NFW), Burkert, and Pseudo-Isothermal (ISO)
profiles. Through the results we conclude that the BDM profile fits better, or
equally well, than NFW, Burkert, and ISO profiles and agree with previous
results implying that cored profiles are preferred over the N-body motivated
cuspy profile. 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=300 pc and a transition energy Ec = 0.11 eV when the DM halo is the
only component. In Kroupa mass model, we obtain a core rc=1.48 kpc, and energy
Ec=0.06 eV.Comment: 54 pages, 26 Figures. Submitted to Phys. Rev. D. Refer also to
Phys.Rev.D84:121301,201
Galactic phase transition at Ec=0.11 eV from rotation curves of cored LSB galaxies and nonperturbative dark matter mass
We analyze the a set of seventeen rotation curves of Low Surface Brightness
(LSB) galaxies from the The HI Nearby Galaxy Survey (THINGS) with different
mass models to study the core structure and to determine a phase transition
energy scale (E_c) between hot and cold dark matter, due to nonperturbative
effects in the Bound Dark Matter (BDM) model. Our results agree with previous
ones implying the cored profiles are preferred over the N-body motivated cuspy
NFW profile. We find an average galactic core radius of r_c = 260 \times
10^{+/- 1.3} pc and a phase transition energy E_c = 0.11\times 10^{+/- 0.46}
eV, that is of the same order of magnitude as the sum of the neutrino masses.Comment: 5 pages, 1 figure