The puzzle of dark matter halo cores in low- and high redshift galaxies
In the present Universe, especially low-mass galaxies reveal central dark halo properties that
indicate a dark core of constant density and constant velocity dispersion. This is in strong contrast
to cold-dark-matter simulations that predict cuspy, cold cores with a density that diverges towards the center as 1/r,
with a velocity dispersion that decreases towards the center. Several scenarios to explain this discrepancy
are currently being discussed, from gravitational
interaction betwen baryons and dark matter to hidden properties of dark matter particles.
I will discuss new properties about dark matter cores, that we detected recently not only in low-redshift galaxies but also
for a large sample of high-z, star-forming disk galaxies. These scaling relations provide more insight into the
process of core formation with implications for the intimate coupling between baryons and dark matter and the possible
nature of dark matter particle itself.