distance scale; galaxies: kinematics and dynamics; gravitational lensing: strong; Anisotropic models; Axisymmetric; Distance scale; Galaxies: Kinematics and dynamics; Gravitational lensing: strong; Kinematic data; Projection effects; Random uncertainties; Time-delays; Velocity dispersion; Astronomy and Astrophysics; Space and Planetary Science
Abstract :
[en] Context. Constraining the mass-sheet degeneracy (MSD) is crucial for improving the precision and accuracy of time-delay cosmography. Joint analyses based on lensing and stellar kinematics have been widely adopted to break the MSD. A three-dimensional (3D) mass and stellar tracer population is required to accurately interpret the kinematics data. Aims. Our forward-modeling procedure is aimed at evaluating the projection effects using strong lensing and kinematics observables and to determine an optimal model assumption for the stellar kinematics analysis leading to an unbiased interpretation of the MSD and H0. Methods. We numerically simulated the projection and selection effects for both a triaxial early-type galaxy (ETG) sample from the TNG100 simulation and an axisymmetric sample that matches the properties of slow-rotator galaxies representative of the strong lens galaxy population. Using the axisymmetric sample, we generated mock kinematics observables with spherically aligned axisymmetric Jeans anisotropic modeling (JAM) and assessed the kinematic recovery under different model assumptions. Using the triaxial sample, we quantified the random uncertainty introduced by modeling triaxial galaxies with axisymmetric JAM. Results. We show that spherical JAM analysis of spatially unresolved kinematic data introduces a bias of up to 2–4% (depending on the intrinsic shape of the lens) in the inferred MSD. Our model largely corrects this bias, resulting in a residual random uncertainty in the range of 0–2.2% in the stellar velocity dispersion (0–4.4% in H0), depending on the projected ellipticity and the anisotropy of the stellar orbits. This residual uncertainty can be further mitigated by the use of spatially resolved kinematic data, which constrain the intrinsic axis ratio. We also show that the random uncertainty in the kinematics recovery using axisymmetric JAM for axisymmetric galaxies is at the level of 0.24% in the velocity dispersion, and the uncertainty using axisymmetric JAM for triaxial galaxies is at the level of 0.17% in the velocity dispersion.
Research Center/Unit :
STAR - Space sciences, Technologies and Astrophysics Research - ULiège
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Huang, Xiang-Yu ; Department of Physics and Astronomy, Stony Brook University, Stony Brook, United States
Birrer, Simon ; Department of Physics and Astronomy, Stony Brook University, Stony Brook, United States
Cappellari, Michele ; Sub-Department of Astrophysics, Department of Physics, University of Oxford, Oxford, United Kingdom
Treu, Tommaso ; Department of Physics and Astronomy, University of California, Los Angeles, United States
Knabel, Shawn ; Department of Physics and Astronomy, University of California, Los Angeles, United States
Sluse, Dominique ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO)
Language :
English
Title :
XXII. Triaxiality and projection effects in time-delay cosmography
Gordon and Betty Moore Foundation F.R.S.-FNRS - Fonds de la Recherche Scientifique NSF - National Science Foundation
Funding number :
4.4503.1
Funding text :
The software/packages we use in this project are: deproject, Lenstronomy (Birrer & Amara 2018; Birrer et al. 2021), JamPy (Cappellari 2020), MgeFit (Cappellari 2002), hierArc (Birrer et al. 2020), NumPy (Harris et al. 2020), matplotlib (Hunter 2007) and SciPy (Virtanen et al. 2020). HXY thanks Claudia Pulsoni for providing the ETG catalog from the IllustrisTNG simulation. HXY thanks Phil Marshall, William Sheu, Alessandro Sonnenfeld and Veronica Motta for useful discussions and comments. HXY and SB are partially supported by the Department of Physics and Astronomy, Stony Brook University. TT acknowledges support by NSF through grants NSF-AST-1906976, NSF-AST-1836016, NSF-AST-2407277, and from the Moore Foundation through grant 8548. DS acknowledges the support of the Fonds de la Recherche Scientifique-FNRS, Belgium, under grant No. 4.4503.1.The software/packages we use in this project are: DEPROJECT , L ENSTRONOMY (; ), J AM P Y (), M GE Fit (), HIER A RC (), NUM P Y (), MATPLOTLIB () and S CI P Y (). HXY thanks Claudia Pulsoni for providing the ETG catalog from the IllustrisTNG simulation. HXY thanks Phil Marshall, William Sheu, Alessandro Sonnenfeld and Veronica Motta for useful discussions and comments. HXY and SB are partially supported by the Department of Physics and Astronomy, Stony Brook University. TT acknowledges support by NSF through grants NSF-AST-1906976, NSF-AST-1836016, NSF-AST-2407277, and from the Moore Foundation through grant 8548. DS acknowledges the support of the Fonds de la Recherche Scientifique-FNRS, Belgium, under grant No. 4.4503.1.
