Gravitational lensing around dark matter in galactic halo region

The presence of dark matter in the galactic region has decisively confirmed by astronomical observations , however, the characteristics of dark matter yet to be recognized correctly. Utilizing the Einstein's general theory of relativity and the observed rotational curve profile as input, we point out some features of galactic dark matter. Usually, dark matter is not directly visible but affects the lensing. In this paper, the deflection of a massive particle by galactic dark matter is studied using the Jacobi metric approach. We also provide a brief analysis of the image features of the deflection angle.