Cosmographic constraints on a Gödel-type rotating universe

Abstract

We investigate the possibility of global cosmic rotation using a Gödel-type rotating cosmological model, constrained through a cosmographic analysis of Type Ia supernovae (SNIa) from the Pantheon+ dataset. Employing a Taylor-expanded apparent magnitude--redshift relation derived via the Kristian-Sachs formalism, we analyze low-redshift SNIa data across five redshift bins (up to $Z\le 0.5$). Our results reveal a mild but consistent preference for cosmic rotation, with the dimensionless rotation parameter ${\Omega }_0$ peaking at $0.29_{-0.15}^{+0.21}$ for $Z\le 0.2$, and a broadly aligned anisotropy axis centered around equatorial coordinates $(243^{\circ },-49^{\circ })$. The inferred Hubble constant $h_0\approx 0.73$ remains stable across all bins, while the deceleration parameter $q_0$ trends from near-zero to mildly negative values with increasing redshift. Model comparison using the Akaike Information Criterion (AIC) indicates a statistically significant preference for the rotating model over the standard $\Lambda$CDM cosmology at intermediate redshifts. These findings suggest that cosmic rotation, if present, may influence the late-time expansion history of the universe and warrants further investigation beyond the cosmographic regime.

20 pages, 5 figures, 1 Table. Comments are welcome