Probing hybrid modified gravity by stellar motion around Galactic Centre

Abstract

We consider possible signatures for the so called {\it hybrid gravity} within the Galactic Central Parsec. This modified theory of gravity consists of a superposition of the metric Einstein-Hilbert Lagrangian with an $f(R)$ term constructed {\it à la Palatini} and can be easily reduced to an equivalent scalar-tensor theory. Such an approach is introduced in order to cure the shortcomings related to $f(R)$ gravity, in general formulated either in metric or in metric-affine frameworks. Hybrid gravity allows to disentangle the further gravitational degrees of freedom with respect to those of standard General Relativity. The present analysis is based on the S2 star orbital precession around the massive compact dark object at the Galactic Centre where the simulated orbits in hybrid modified gravity are compared with astronomical observations. These simulations result with constraints on the range of hybrid gravity interaction parameter ${\varphi }_0$, showing that in the case of S2 star it is between -0.0009 and -0.0002. At the same time, we are also able to obtain the constraints on the effective mass parameter $m_{\varphi }$, and found that it is between -0.0034 and -0.0025 AU${}^{-1}$ for S2 star. Furthermore, the hybrid gravity potential induces precession of S2 star orbit in the same direction as General Relativity. In previous papers, we considered other types of extended gravities, like metric power law $f(R)\propto R^n$ gravity, inducing Yukawa and Sanders-like gravitational potentials, but it seems that hybrid gravity is the best among these models to explain different gravitational phenomena at different astronomical scales.

11 pages, 4 figures, accepted for publication in Astroparticle Physics

References in corpus (21)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Resummation of Massive Gravity
• Cosmological viability of f(R)-gravity as an ideal fluid and its compatibility with a matter dominated phase
• Palatini Approach to Modified Gravity: f(R) Theories and Beyond
• Conditions for the cosmological viability of f(R) dark energy models
• Are f(R) dark energy models cosmologically viable ?
• Low surface brightness galaxies rotation curves in the low energy limit of $R^n$ gravity : no need for dark matter?
• Infrared-modified gravities and massive gravitons
• Wormholes supported by hybrid metric-Palatini gravity
• Analysis of Rotation Curves in the framework of R^n gravity
• The recovery of General Relativity in massive gravity via the Vainshtein mechanism
• Cosmology of hybrid metric-Palatini f(X)-gravity
• Orbital precession due to central-force perturbations
• Power-law cosmic expansion in f(R) gravity models
• Solar system constraints on R${}^n$ gravity
• Constraints on $R^n$ gravity from precession of orbits of S2-like stars
• Apoastron Shift Constraints on Dark Matter Distribution at the Galactic Center
• Gravitational lensing in fourth order gravity
• A general solution in the Newtonian limit of f(R)- gravity
• Constraints on $R^n$ gravity from precession of orbits of S2-like stars: a case of a bulk distribution of mass
• The most general fourth order theory of Gravity at low energy

Cited by in corpus (22)

• Testing General Relativity with stellar orbits around the supermassive black hole in our Galactic center
• Hybrid metric-Palatini gravity
• Scalar field effects on the orbit of S2 star
• Test-particle dynamics in general spherically symmetric black hole spacetimes
• Beyond Einstein's General Relativity: Hybrid metric-Palatini gravity and curvature-matter couplings
• Modified gravity revealed along geodesic tracks
• Dark energy interactions near the galactic centre
• Constraining Non-local Gravity by S2 star orbits
• Estimating the Parameters of Extended Gravity Theories with the Schwarzschild Precession of S2 Star
• Constraints on Yukawa gravity parameters from observations of bright stars
• The Galactic Center as a laboratory for theories of gravity and dark matter
• Testing modified gravity via Yukawa potential in two body problem: Analytical solution and observational constraints
• Influence of bulk mass distribution on orbital precession of S2 star in Yukawa gravity
• Estimating the parameters of Hybrid Palatini gravity model with the Schwarzschild precession of S2, S38 and S55 stars: case of bulk mass distribution
• Black Hole Perturbations and Quasinormal Modes in Hybrid Metric-Palatini Gravity
• PPN motion of the S-stars around Sgr A*
• Dark Energy as a Critical Period in Binary Motion: Bounds from Multi-scale Binaries
• Possible effects of Hybrid Gravity on stellar kinematics in elliptical galaxies
• Kerr-scalaron metric and astronomical consequences near the Galactic Center black hole
• Constraining primordial black hole masses through $f(R)$ gravity scalarons in Big Bang Nucleosynthesis
• Evolving Wormholes in a Cosmological Background
• Extended Theories of Gravity in cosmological and astrophysical applications