Mirror Matter, Mirror Gravity and Galactic Rotational Curves

A bigravity theory where the normal and dark matter components are coupled to separate metric fields linked to each-other with small non-derivative terms allows the Yukawa-like modification of the gravitational potential at large distances. This opens new prospects for the dark matter candidates. Namely, instead of being cold and collisionless, dark matter can be collisional and dissipative, as it occurs in the case of mirror matter that presumably does not form extended halos but is clumped similarly to visible matter. We show that the flattening of the galactic rotational curves can be explained if the typical scale of the Yukawa-like potential is about few tens of kpc and if the mass ratio between dark matter and visible matter in galaxies is about 10. [email protected] [email protected] [email protected]