Unified lensing and kinematic analysis for any elliptical mass profile
Abstract
We demonstrate an efficient method to compute the strong-gravitational-lensing deflection angle and magnification for any elliptical surface density profile. This method solves a numerical hurdle in lens modelling that has lacked a general solution for nearly three decades. The hurdle emerges because it is prohibitive to derive analytic expressions of the lensing quantities for most elliptical mass profiles. In our method, we first decompose an elliptical mass profile into concentric Gaussian components. We introduce an integral transform that provides us with a fast and accurate algorithm for this Gaussian decomposition. We derive analytic expressions of the lensing quantities for a Gaussian component. As a result, we can compute these quantities for the total mass profile by adding up the contributions from the individual components. This lensing analysis self-consistently completes the kinematic description in terms of Gaussian components presented by Cappellari (2008). Our method is general without extra computational burden unlike other methods currently in use.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 2019
- DOI:
- 10.1093/mnras/stz1796
- arXiv:
- arXiv:1906.08263
- Bibcode:
- 2019MNRAS.488.1387S
- Keywords:
-
- gravitational lensing: strong;
- methods: analytical;
- methods: data analysis;
- methods: numerical;
- galaxies: kinematics and dynamics;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 11 pages + appendices, 6 figures, submitted to MNRAS. An interactive jupyter notebook version of this paper is accessible on Google colab at https://colab.research.google.com/drive/10jw5T07mhvdP0hp60HqVqNqWK49Cfzby