Resolution-corrected White Dwarf Gravitational Redshifts Validate Fifth-generation Sloan Digital Sky Survey Wavelength Calibration and Enable Accurate Mass–Radius Tests
Abstract Leveraging the large sample size of low-resolution spectroscopic surveys to constrain white dwarf stellar structure requires an accurate understanding of the shapes of hydrogen absorption lines, which are pressure broadened by the Stark effect. Using data from both the Sloan Digital Sky Survey (SDSS) and the Type Ia Supernova Progenitor Survey, we show that substantial biases (5–15 km s −1 ) exist in radial velocity measurements made from observations at low spectral resolution relative to similar measurements from high-resolution spectra. Our results indicate that the physics of line formation in high-density plasmas, especially in the wings of the lines, are not fully accounted for in state-of-the-art white dwarf model atmospheres. We provide corrections to account for these resolution-induced redshifts in a way that is independent of an assumed mass–radius relation, and we demonstrate that statistical measurements of gravitational redshift with these corrections yield improved agreement with theoretical mass–radius relations. Our results provide a set of best practices for white dwarf radial velocity measurements from low-resolution spectroscopy, including those from SDSS, the Dark Energy Spectroscopic Instrument, the 4 m Multi-Object Spectroscopic Telescope, and the Wide-Field Multiplexed Spectroscopic Facility.
Authors
- Gautham Adamane Pallathadka (ORCID: https://orcid.org/0000-0002-5864-1332)
- Vedant Chandra (ORCID: https://orcid.org/0000-0002-0572-8012)
- Nicole R. Crumpler (ORCID: https://orcid.org/0000-0002-8866-4797)
- Boris Gaensicke (ORCID: https://orcid.org/0000-0002-2761-3005)
- J. J. Hermes (ORCID: https://orcid.org/0000-0001-5941-2286)
- Kareem J. El-Badry (ORCID: https://orcid.org/0000-0002-6871-1752)
- N. P. Gentile Fusillo (ORCID: https://orcid.org/0000-0002-6428-4378)
- Nadia L. Zakamska (ORCID: https://orcid.org/0000-0001-6100-6869)
- Stefan Arseneau (ORCID: https://orcid.org/0000-0002-6270-8624)
- Carles Badenes (ORCID: https://orcid.org/0000-0003-3494-343X)
Institutions
- Boston University (US)
- California Institute of Technology (US)
- University of Trieste (IT)
- Johns Hopkins University (US)
- University of Pittsburgh (US)
- Trieste Astronomical Observatory (IT)
- University of Warwick (GB)
- Center for Astrophysics Harvard & Smithsonian (US)
- University of Baltimore (US)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-09-26
- DOI
- https://doi.org/10.3847/1538-4357/adf8dd
- Primary Topic
- Stellar, planetary, and galactic studies
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- Smithsonian Institution
- Alfred P. Sloan Foundation
- Yale University
- Carnegie Institution of Washington
- Ohio State University
- California Institute of Technology
- Harvard University
- Johns Hopkins University
- New Mexico State University
- Space Telescope Science Institute
- European Space Agency
- Flatiron Health
- École Polytechnique Fédérale de Lausanne
- University of Toronto
- Universidad Nacional Autónoma de México
- Yunnan University
- Nanjing University
- China National Textile and Apparel Council
- Leibniz-Institut für Astrophysik Potsdam
- Max-Planck-Institut für Astronomie
- University of Illinois at Urbana-Champaign
- University of Colorado Boulder
- Smithsonian Astrophysical Observatory
- Leibniz-Gemeinschaft
- National Astronomical Observatories, Chinese Academy of Sciences