TDCOSMO
Spatially resolved stellar kinematics has become a key ingredient in time-delay cosmography to break the mass-sheet degeneracy in the mass profile and in turn provide a precise constraint on the Hubble constant and other cosmological parameters. In this paper, we present the first measurements of 2D resolved stellar kinematics for the lens galaxy in the quadruply lensed quasar system RXJ1131−1231 using integral field spectroscopy from JWST’s Near-Infrared Spectrograph (NIRSpec), marking the first such measurement conducted with JWST. In extracting robust kinematic measurements from this first-of-its-kind dataset, we have made methodological improvements both in the data reduction and kinematic extraction. In our kinematic extraction procedure, we performed joint modeling of the lens galaxy, the quasar, and its host galaxy’s contributions in the spectra to deblend the lens galaxy component and robustly constrain its stellar kinematics. Our improved methodological frameworks are released as software pipelines for future use: SQUIRREL , for extracting stellar kinematics, and R EGAL J UMPER , for JWST-NIRSpec data reduction. We incorporated additional artifact cleaning beyond the standard JWST pipeline. We compared our measured stellar kinematics from the JWST NIRSpec with previously obtained ground-based measurements from the Keck Cosmic Web Imager integral field unit and find that the two datasets are statistically consistent at a ∼1.1 σ confidence level. Our measured kinematics will be used in a future study to improve the precision of the Hubble constant measurement.
Authors
- Dominique Sluse (ORCID: https://orcid.org/0000-0001-6116-2095)
- Simon Birrer (ORCID: https://orcid.org/0000-0003-3195-5507)
- C. D. Fassnacht (ORCID: https://orcid.org/0000-0002-4030-5461)
- F. Courbin (ORCID: https://orcid.org/0000-0003-0758-6510)
- J. Frieman (ORCID: https://orcid.org/0000-0003-4079-3263)
- Tommaso Treu (ORCID: https://orcid.org/0000-0002-8460-0390)
- Shawn Knabel (ORCID: https://orcid.org/0000-0001-5110-6241)
- Michele Cappellari (ORCID: https://orcid.org/0000-0002-1283-8420)
- Takahiro Morishita (ORCID: https://orcid.org/0000-0002-8512-1404)
- Akın Yıldırım (ORCID: https://orcid.org/0000-0003-1693-7669)
- Alejandra Melo (ORCID: https://orcid.org/0000-0002-6449-3970)
- S. H. Suyu (ORCID: https://orcid.org/0000-0001-5568-6052)
- Anowar J. Shajib (ORCID: https://orcid.org/0000-0002-5558-888X)
- M. Stiavelli (ORCID: https://orcid.org/0000-0001-9935-6047)
- David R. Law (ORCID: https://orcid.org/0000-0002-9402-186X)
- Pritom Mozumdar
- A. Galan (ORCID: https://orcid.org/0000-0003-2547-9815)
- Han Wang (ORCID: https://orcid.org/0000-0002-1293-5503)
Institutions
- Institució Catalana de Recerca i Estudis Avançats (ES)
- California Institute of Technology (US)
- Space Telescope Science Institute (US)
- University of Liège (BE)
- University of Oxford (GB)
- University of Chicago (US)
- Kavli Institute for Particle Astrophysics and Cosmology (US)
- Max Planck Institute for Astrophysics (DE)
- Institut Català de Ciències del Clima (ES)
- Astronomy and Space (AU)
- Infrared Processing and Analysis Center (US)
- Stony Brook University (US)
- Technical University of Munich (DE)
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2026-02-03
- DOI
- https://doi.org/10.1051/0004-6361/202556126
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00