Constraining the Rastall parameters in static space–times with galaxy-scale strong gravitational lensing

Abstract

Recently, Rastall gravity is undergoing a significant surge in popularity. We obtain a power-law total mass-density profile for the inner region (within several effective radius) of early-type galaxies (ETGs) from the space-time structures which are described by the static spherically-symmetric solutions of Rastall gravity under the assumption of perfect fluid matter. We find that in the inner region of ETGs, the Rastall dimensionless parameter β = κλ determines the mass distribution. We then use 118 galaxy-galaxy strong gravitational lensing systems to constrain the Rastall dimensionless parameter β. We find that the mean value of β for total 118 ETGs is β = 0.163 ± 0.001(68% CL) with a minor intrinsic scatter of δ = 0.020 ± 0.001. Our work observationally illustrates the physical meaning of the Rastall dimensionless parameter in galaxy scale. From the Newtonian approximation of Rastall gravity, we also find that an absolute isothermal mass distribution for ETGs is not allowed in the framework of Rastall gravity.

Thin-shell wormholes in Rastall gravity

“…Positive values of λ increased the stability regions whereas negative values decreased them in comparison to General Relativity. It should be remarked that the values of the Rastall parameter considered here are consistent with the ones obtained from a statistical analysis of 118 galaxy-galaxy strong gravitational lensing systems within the context of RG [41]. Remarkably, we found that for the radiation case (extremal and non-extremal cases) is possible to have thin-shell wormholes supported by nonrelativistic matter provided the relation β 0 = v 2 sound ≪ 1 holds.…”

“…Besides, the statistical analysis based on the galaxy-galaxy strong gravitational lensing indicated that the Rastall' s parameter β = κλ is non-zero but is order of unity [41], supporting the idea that at the galactic scale it is possible to distinguish both theories. Moreover, the Bayesian analysis performed to constrain the rotation curves of 16 low surface brightness spiral galaxies showed that the Rastall's parameter β is of order 10 −1 [42], which is consistent with the strong lensing estimation [41]. At the cosmological scale, the supernovae type Ia data associated with the Constitution sample put stronger bounds on the Rastall's parameter, yielding to β ≃ O(10 −4 ) [43,44].…”

“…(40)a n d( 41), we must consider small perturbations around their static solutions. Given (40)a n d ( 41) we confirm that the aforesaid equations satisfy the conservation equation (31). We employ the set of Eqs.…”

“…In fact, some authors claimed that the Rastall theory may be in accordance with the Mach principle for a gravity theory in the sense that the local matter configurations depend on the distribution of matter of the whole spacetime [40]. Besides, the statistical analysis based on the galaxy-galaxy strong gravitational lensing indicated that the Rastall' s parameter β = κλ is non-zero but is order of unity [41], supporting the idea that at the galactic scale it is possible to distinguish both theories. Moreover, the Bayesian analysis performed to constrain the rotation curves of 16 low surface brightness spiral galaxies showed that the Rastall's parameter β is of order 10 −1 [42], which is consistent with the strong lensing estimation [41].…”

Rastall gravity extension of the standard $$\Lambda $$CDM model: theoretical features and observational constraints

“…Using realistic equations of state for the neutron star interior, an astrophysical constraint is placed on the Rastall gravity suggests that it is well consistent with GR as | | 10 −2 [99]. In contrast, the study [100] on much larger scales, using 118 galaxy-galaxy strong gravitational lensing systems, reports the constraint = −0.163 ± 0.001 (68% CL) excluding GR. Here, we study the robust and accurate observational constraints on the Rastall gravity extension of the standard CDM model.…”