A new constant behind the rotational velocity of galaxies

Abstract

The present work is devoted to studying the dynamical evolution of galaxies in scalar-Gauss-Bonnet gravity and its relationship with the MOND paradigm. This study is useful for giving meaning to the presence of a new gravitational constant. The stability of dark matter is strongly dependent on matter density. We are interested in calculating the maximum rotational velocity of galaxies. We show that rotating galaxies can be described by a new parameter that depends both on the minimum value of scalar fields and on the effective mass of this field. According to observational data, we have shown that this parameter is a constant.

Interpretation of galaxy rotation curves from primordial black holes in 4D Einstein-Gauss-Bonnet gravity

“…We will also point out that there is the presence of two gravitational constants, the first is that of Newton's constant, the second appears more for very intense gravity (like galaxies). We will show why the values of the constant θ 0 in [12] for the dwarf spheroidal and irregular dwarf galaxies are not constant. We show the presence of primordial black holes in the dark matter halos according to the rotation curves of galaxies.…”

“…The gravitational potential is writing as ∇ 2 V = 4πGρ m [35]. Using the massvelocity relationship as is shown in [12], we notice that ∂ 2 f (φ min ) /∂φ 2 = GM/KV 2 , where V is the rotation velocity of the galaxy disk and K is a constant, which roughly equals K ≈ 69.44kg −1/2 km −1/2 and θ 0 = (KM ef f ) −1/2 [12]. The total mass of the galaxy M is integrated mass within some the galaxy radius r max as M = rmax 0 4πr 2 ρ m (r) dr.…”

“…Although the EGB gravity is currently debatable, the spherically symmetric black hole solution is still meaningful and worthy of study [24]. In [12] we have studied the relationship between the MOND paradigm and scalar-Gauss-Bonnet (EsGB) gravity, we added a new relativistic part to the MOND from EsGB gravity.…”

Cosmic acceleration in Lovelock quantum gravity

“…We notice that α k are the Lovelock coupling constants with dimensions (length) 2k−D , where D is the respective dimension. Here, α 2 = α and α 3 are respectively the second (Gauss-Bonnet coupling [36,37]) and the third Lovelock coefficients. The zero-order Lovelock invariant is…”