Improved Lemaitre-Tolman model and the mass and turn-around radius in group of galaxies

Understand

We extended the modified Lemaitre-Tolman model taking into account the effect of angular momentum and dynamical friction.

• The inclusion of these quantities in the equation of motion modifies the evolution of a perturbation, initially moving with the Hubble flow.
• Solving the equation of motions we got the relationships between mass, $M$, and the turn-around radius, $R_0$.
• Knowing $R_0$, the quoted relation allows the determination of the mass of the object studied.