J factor Computation - adam-coogan/GRAPPA_Student_Seminar_2019 GitHub Wiki
Analytical Solution to a simplified dark matter profile
Coordinates transformations and definitions. GC:= Galactic centre, GW:= Galactic West, GE:= Galactic East, SGP:= South Galactic Pole, NGP:= North Galactic Pole (Image credit:M. Hütten, C. Combet and D. Maurin).
We want to make a coordinates transformation from heliocentric coordinates to Galactocentric coordinates. Assuming that the GC is located at distance R_sun we can write
The astrophysical factor in the (theta,Psi) direction is obtained by integrating over the line of sight the dark matter density squared profile
We can use a simplified form for the dark matter profile to obtain an analytical solution to the line-of-sight integration like shown below: