Cosmological model-independent constraints on spatial curvature from strong gravitational lensing and type Ia supernova observations

TL;DR

This study uses strong gravitational lensing and supernova data to constrain the universe's spatial curvature without relying on specific cosmological models, highlighting the influence of lens models and data classification.

Contribution

It provides a model-independent method to estimate cosmic curvature using new datasets and compares results across different lens models and data classifications.

Findings

Flat universe supported in SIS and power-law models with ~0.2 uncertainty

Closed universe preferred in power-law lens model

Lens model choice significantly affects curvature constraints

Abstract

Applying the distance sum rule in strong gravitational lensing (SGL) and type Ia supernova (SN Ia) observations, one can provide an interesting cosmological model-independent method to determine the cosmic curvature parameter $\Omega_k$. In this paper, with the newly compiled data sets including 161 galactic-scale SGL systems and 1048 SN Ia data, we place constraints on $\Omega_k$ within the framework of three types of lens models extensively used in SGL studies. Moreover, to investigate the effect of different mass lens samples on the results, we divide the SGL sample into three sub-samples based on the center velocity dispersion of intervening galaxies. In the singular isothermal sphere (SIS) and extended power-law lens models, a flat universe is supported with the uncertainty about 0.2, while a closed universe is preferred in the power-law lens model. We find that the choice of lens models and the classification of SGL data actually can influence the constraints on $\Omega_k$ significantly.