A Model-independent Determination of the Hubble Constant from Lensed Quasars and Supernovae Using Gaussian Process Regression
Abstract
Strongly lensed quasar systems with time delay measurements provide “time delay distances,” which are a combination of three angular diameter distances and serve as powerful tools to determine the Hubble constant H 0. However, current results often rely on the assumption of the ΛCDM model. Here we use a model-independent method based on Gaussian process to directly constrain the value of H 0. By using Gaussian process regression, we can generate posterior samples of unanchored supernova distances independent of any cosmological model and anchor them with strong lens systems. The combination of a supernova sample with large statistics but no sensitivity to H 0 with a strong lens sample with small statistics but H 0 sensitivity gives a precise H 0 measurement without the assumption of any cosmological model. We use four well-analyzed lensing systems from the state-of-art lensing program H0LiCOW and the Pantheon supernova compilation in our analysis. Assuming the universe is flat, we derive the constraint H 0 = 72.2 ± 2.1 km s-1 Mpc-1, a precision of 2.9%. Allowing for cosmic curvature with a prior of Ω k = [-0.2, 0.2], the constraint becomes {H}0={73.0}-3.0+2.8 {km} {{{s}}}-1 {Mpc}}-1.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2019
- DOI:
- 10.3847/2041-8213/ab5308
- arXiv:
- arXiv:1908.04967
- Bibcode:
- 2019ApJ...886L..23L
- Keywords:
-
- Hubble constant;
- Cosmological parameters;
- Strong gravitational lensing;
- Dark energy;
- 758;
- 339;
- 1643;
- 351;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 7 pages, 5 figures. Accepted for publication in ApJ Letters