  We discuss the possibility that the cold dark matter mass profiles contain
information on the cosmological constant, and that such information constrains
the nature of cold dark matter (CDM). We call this approach Modified Dark
Matter (MDM). In particular, we examine the ability of MDM to explain the
observed mass profiles of 13 galaxy clusters. Using general arguments from
gravitational thermodynamics, we provide a theoretical justification for our
MDM mass profile and successfully compare it to the NFW mass profiles both on
cluster and galactic scales. Our results suggest that indeed the CDM mass
profiles contain information about the cosmological constant in a non-trivial
way.
