  Various astrophysical and cosmological observations today serve as an
indirect evidence of the existence of dark matter in the universe. In the
present work, we propose a class of spacetimes that show some important
characteristics relevant to the spacetime of a dark matter halo. These
spacetimes are static and spherically symmetric solutions of the Einstein field
equations. The proposed spacetimes satisfy the flat velocity profile of a
galactic object far away from the center, they give good agreement to the
astrometric data of the S2 star, and these also cast a central shadow. Using
the Penrose diagram, we show that the causal nature of the central singularity
here is null. This single spacetime model for galactic dark matter may
therefore be used to explain some of the properties of galactic dynamics at
different length scales.
