Strongly lensed type Ia supernovae as a precise late-Universe probe of measuring the Hubble constant and cosmic curvature

Strongly lensed type Ia supernovae (SNe Ia) are expected to have some advantages in measuring time delays of multiple images, and so they have a great potential to be developed into a powerful late-Universe cosmological probe. In this paper, we simulate a sample of lensed SNe la with time-delay measurements in the era of the Legacy Survey of Space and Time (LSST). Based on the distance sum rule, we use lensed SNe Ia to implement cosmological model-independent constraints on the Hubble constant H o and cosmic curvature parameter Omega(k) in the late Universe. We find that if 20 lensed SNe Ia could be observed, the constraint on H-0 is better than the measurement by the SHOES Collaboration. When the event number of lensed SNe Ia increases to 100, the constraint precision of H-0 is comparable with the result from Planck 2018 data. Considering 200 lensed SNe Ia events as the optimistic estimation, we obtain Delta H-0 = 0.33 km s(-1) Mpc(-1) and Delta Omega(k) = 0.053. In addition, we also simulate lensed quasars in different scenarios to make a comparison and we find that they are still a useful cosmological probe even though the constraint precision from them is much less than that obtained from lensed SNe Ia. In the era of LSST, the measurements of time delay from both lensed SNe Ia and lensed quasars are expected to yield the results of Delta H-0 = 0.26 km s (-1) Mpc(-1) and Delta Omega(k) = 0.044.

Automated summary

In this paper, the authors simulate a sample of lensed SNe Ia with time-delay measurements and demonstrate their potential as a powerful cosmological probe. They find that the constraint on the Hubble constant obtained from lensed SNe Ia is better than previous measurements, and can be comparable to the result from Planck 2018 data. The authors also compare lensed quasars and find that they are still useful but less precise as a cosmological probe. The results from both lensed SNe Ia and lensed quasars in the era of LSST are expected to yield valuable information on the Hubble constant and cosmic curvature parameter.