Newest Measurements of Cosmic Curvature with BOSS/eBOSS and DESI DR1 Baryon Acoustic Oscillation Observations

Abstract Determining the cosmic curvature (Ω K ) independent of cosmological models plays a key role in revealing the background physics of our Universe. In this Letter, we propose an improved method to measure the cosmic curvature using the observations of baryon acoustic oscillations (BAO). It is important to highlight that our method circumvents the influence induced by the Hubble constant ( H 0 ) and the sound horizon ( r d ) in BAO observations. We use the newest BAO observations from Baryon Oscillation Spectroscopic Survey (BOSS)/Extended Baryon Oscillation Spectroscopic Survey (eBOSS) and Dark Energy Spectroscopic Instrument (DESI) surveys. By taking into account the information of cosmic chronometers reconstructed from two machine learning methods (Gaussian process and artificial neural network), we demonstrate that one can achieve constraint on the cosmic curvature with ∣Ω K ∣ < 0.04 and ∣Ω K ∣ < 0.01. Further comparative analysis of the BOSS/eBOSS and DESI DR1 observations indicates that there is almost no difference between the two BAO samples at the current observational level. Therefore, our results confirm that the newest BAO observations provide a cosmological model–independent tool to verify the flatness of the Universe.