Test of Einstein equivalence principle near the Galactic center supermassive black hole

Abstract

During its orbit around the four million solar mass black hole Sagittarius A* the star S2 experiences significant changes in gravitational potential. We use this change of potential to test one part of the Einstein equivalence principle: the local position invariance (LPI). We study the dependency of different atomic transitions on the gravitational potential to give an upper limit on violations of the LPI. This is done by separately measuring the redshift from hydrogen and helium absorption lines in the stellar spectrum during its closest approach to the black hole. For this measurement we use radial velocity data from 2015 to 2018 and combine it with the gravitational potential at the position of S2, which is calculated from the precisely known orbit of S2 around the black hole. This results in a limit on a violation of the LPI of $|{\beta }_{He}-{\beta }_H|=(2.4\pm 5.1)\cdot 10^{-2}$. The variation in potential that we probe with this measurement is six magnitudes larger than possible for measurements on Earth, and a factor ten larger than in experiments using white dwarfs. We are therefore testing the LPI in a regime where it has not been tested before.

Accepted for publication in Physical Review Letters

References in corpus (14)

• The Confrontation between General Relativity and Experiment
• Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
• An Update on Monitoring Stellar Orbits in the Galactic Center
• An Improved Distance and Mass Estimate for Sgr A* from a Multistar Orbit Analysis
• Twelve years of spectroscopic monitoring in the Galactic Center: the closest look at S-stars near the black hole
• On the nature of the fast moving star S2 in the Galactic Center
• Dynamical Imaging with Interferometry
• Tests of local position invariance using continuously running atomic clocks
• Is there a Supermassive Black Hole at the Center of the Milky Way?
• Variation of fundamental constants: theory and observations
• EELT-HIRES the high-resolution spectrograph for the E-ELT
• How changing physical constants and violation of local position invariance may occur?
• Limits on gravitational Einstein Equivalence Principle violation from monitoring atomic clock frequencies during a year
• MICADO: first light imager for the E-ELT

Cited by in corpus (21)

• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• Gravitational Test Beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole
• Asymptotic safety casts its shadow
• Search for a Variation of the Fine Structure around the Supermassive Black Hole in Our Galactic Center
• Gravitational lensing of a Schwarzschild-like black hole in Kalb-Ramond gravity
• Where intermediate-mass black holes could hide in the Galactic Centre: A full parameter study with the S2 orbit
• Probing the Black Hole Metric. I. Black Hole Shadows and Binary Black-Hole Inspirals
• Towards an observational test of black hole versus naked singularity at the galactic center
• First Light for GRAVITY Wide: Large Separation Fringe Tracking for the Very Large Telescope Interferometer
• Constraining ultralight bosonic dark matter with Keck observations of S2's orbit and kinematics
• A new line on the wide binary test of gravity
• Event horizon silhouette: implications to supermassive black holes M87* and SgrA*
• Gravitational atoms in the braneworld scenario
• New test on the Einstein equivalence principle through the photon ring of black holes
• Constraining modified gravity theories with scalar fields using black-hole images
• Cosmological test of local position invariance from the asymmetric galaxy clustering
• Constraining primordial black hole masses through $f(R)$ gravity scalarons in Big Bang Nucleosynthesis
• Identifying the Event Horizons of Parametrically Deformed Black-Hole Metrics
• Quantum-enabled optical large-baseline interferometry: applications, protocols and feasibility
• Tidal phenomena in the Galactic Center: The curious case of X7
• Visible shapes of black holes M87* and SgrA*