Quark matter as dark matter in modeling galactic halo
  Considering the flat rotation curves as input and treating the matter content in the galactic halo region as quark matter, we have found out a background spacetime metric for the region of the galactic halo. We obtain fairly general conditions that ensure that gravity in the halo region is attractive. We also investigate the stability of circular orbits, along with a different role for quark matter. Bag-model quark matter meeting these conditions therefore provides a suitable model for dark matter. 
Farook Rahaman, P.K.F. Kuhfittig, Ruhul Amin, Gurudas Mandal, Saibal   Ray and Nasarul Islam
gr-qc