Gravitational Lens Time Delays: A Statistical Assessmentof Lens Model Dependences and Implications for the Global Hubble Constant
Time delays between lensed multiple images have been known to provide an interesting probe of the Hubble constant, but such application is often limited by degeneracies with the shape of lens potentials. We propose a new statistical approach to examine the dependence of time delays on the complexity of lens potentials, such as higher-order perturbations, non-isothermality, and substructures. Specifically, we introduce a reduced time delay of the dimensionless form, and explore its behavior analytically and numerically as a function of the image configuration that is characterized by the asymmetry and opening angle of the image pair. In particular we derive a realistic conditional probability distribution for a given image configuration from Monte-Carlo simulations. We find that the probability distribution is sensitive to the image configuration such that more symmetric and/or smaller opening angle image pairs are more easily affected by perturbations on the primary lens potential. On average time delays of double lenses are less scattered than those of quadruple lenses. Furthermore, the realistic conditional distribution allows a new statistical method to constrain the Hubble constant from observed time delays. We find that 15 published time delay quasars constrain the Hubble constant to be H{sub 0} = 70 {+-} 3km s{sup -1} Mpc{sup -1}. While systematic errors coming from the heterogeneous nature of the quasar sample and the uncertainty of the input distribution of lens potentials should be considered, reasonable agreement with other estimates indicates the usefulness of our new approach as a cosmological and astrophysical probe, particularly in the era of large-scale synoptic surveys.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 892577
- Report Number(s):
- SLAC-PUB-12135; astro-ph/0609694; TRN: US200623%%709
- Journal Information:
- The Astrophysical Journal, Journal Name: The Astrophysical Journal
- Country of Publication:
- United States
- Language:
- English
Similar Records
STRIDES: a 3.9 per cent measurement of the Hubble constant from the strong lens system DES J0408-5354
Dissecting the Gravitational Lens B1608 656. II. Precision Measurements of the Hubble Constant, Spatial Curvature, and the Dark Energy Equation of State