Bounds on at the Galactic Center

arXiv:2606.13356 · gr-qc, astro-ph.CO · Submitted 2026-06-11 · Read on arXiv

gr-qc, astro-ph.CO

Submitted: 2026-06-11

Updated: 2026-09-17

Comments: 27 pages, 9 figures

License: http://creativecommons.org/licenses/by/4.0/

The gist: We constrain the cosmological constant, Λ, using astrometric and spectroscopic observations of the S2 star, supplemented by S1 and S14 stars orbiting Sgr A*.

Terminology

Galactic Center — 17× in this paper
Schwarzschild-de Sitter — 7× in this paper
Event Horizon Telescope — 4× in this paper
Adam — 2× in this paper · explained in 2 episodes
Clustering — 2× in this paper · explained in 2 episodes
Consistency — 2× in this paper · explained in 3 episodes
General Relativity — 2× in this paper
Velocity Dispersion — 2× in this paper · explained in 2 episodes
Accuracy — 1× in this paper · explained in 1 episode
Bayesian Framework — 1× in this paper · explained in 3 episodes
Calibration — 1× in this paper · explained in 7 episodes
Core — 1× in this paper · explained in 2 episodes
Cosmic Microwave Background — 1× in this paper
Dark Energy Spectroscopic Instrument — 1× in this paper
Trace — 1× in this paper · explained in 2 episodes
Very Large Telescope — 1× in this paper

Abstract

We constrain the cosmological constant, Λ, using astrometric and spectroscopic observations of the S2 star, supplemented by S1 and S14 stars orbiting Sgr A*. We develop a framework for modelling relativistic stellar orbits in general spherically symmetric spacetimes and perform Bayesian parameter estimation to jointly infer orbital and spacetime parameters. Applying this framework to Schwarzschild-de Sitter spacetime, we obtain upper bounds on Λ. The individual constraints exhibit the expected dependence on the dynamical timescales of the stars, with the longer-period S1 providing the strongest sensitivity. Combining the individual constraints, we obtain Λ 6.9 times10-48 m-2 at 68% credibility and Λ 1.0 times10-38 m-2 at 95% credibility. The 68% constraint is the strongest bound at a comparable dynamical timescale.

Terminology

Abstract

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