The DOI matches its Crossref record; 112 of the 115 references it cites were found in a registry or an index.
Further evidence for a variable fine-structure constant from Keck/HIRES QSO absorption spectra
Open accessAbstract
We have previously presented evidence for a varying fine-structure constant, α, in two independent samples of Keck/HIRES quasi-stellar object (QSO) absorption spectra. Here we present a detailed many-multiplet analysis of a third Keck/HIRES sample containing 78 absorption systems. We also re-analyse the previous samples, providing a total of 128 absorption systems over the redshift range 0.2 < zabs < 3.7. The results, with raw statistical errors, indicate a smaller weighted mean α in the absorption clouds: Δα/α= (−0.574 ± 0.102) × 10−5. All three samples separately yield consistent and significant values of Δα/α. The analyses of low-z (i.e. zabs < 1.8) and high-z systems rely on different ions and transitions with very different dependences on α, yet they also give consistent results. We identify an additional source of random error in 22 high-z systems characterized by transitions with a large dynamic range in apparent optical depth. Increasing the statistical errors on Δα/α for these systems gives our fiducial result, a weighted mean Δα/α= (−0.543 ± 0.116) × 10−5, representing 4.7σ evidence for a varying α. Assuming that Δα/α= 0 at zabs= 0, the data marginally prefer a linear increase in α with time rather than a constant offset from the laboratory value: . The two-point correlation function for α is consistent with zero over 0.2–13 Gpc comoving scales and the angular distribution of Δα/α shows no significant dipolar anisotropy. We therefore have no evidence for spatial variations in Δα/α. We extend our previous searches for possible systematic errors, giving detailed analyses of potential kinematic effects, line blending, wavelength miscalibration, spectrograph temperature variations, atmospheric dispersion and isotopic/hyperfine structure effects. The latter two are potentially the most significant. However, overall, known systematic errors do not explain the results. Future many-multiplet analyses of independent QSO spectra from different telescopes and spectrographs will provide a now crucial check on our Keck/HIRES results.
Overview
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“The claim by (Webb et al. 1999;Murphy et al. 2003;King et al. 2012a) that the Keck/HIRES data indicated that the fine structure constant was smaller in the past relaunched the interest in fundamental constants, both from an experimental and theoretical point of view.”
From Fundamental constants: from measurement to the universe, a window on gravitation and cosmology (2025) · cites this paper as Murphy et al. 2003
In the citing paper
“The analysis (Murphy et al. 2003) relies on 128 absorption spectra, later updated (Murphy et al. 2004) to include 143 absorption systems.”
From Fundamental constants: from measurement to the universe, a window on gravitation and cosmology (2025) · cites this paper as Murphy et al. 2003
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Citations
Cites
CRC Handbook of Chemistry and Physics
(2014) · doi:10.1201/b17118 · Cited by 57,706
Statistical Methods for Research Workers
Fisher, R. A. (1945) · American Journal of Clinical Pathology · doi:10.1093/ajcp/15.11.552b · Cited by 10,883
Handbook of Chemistry and Physics
(1937) · Journal of AOAC INTERNATIONAL · doi:10.1093/jaoac/20.1.142a · Cited by 4,759
Quantum Mechanics of One- and Two-Electron Systems
Bethe, H. A., & Salpeter, E. E. (1957) · Handbuch der Physik · doi:10.1007/978-3-642-45869-9_2 · Cited by 4,677
Handbook of Chemistry and Physics.
(1973) · Annals of Internal Medicine · doi:10.7326/0003-4819-79-6-934_3 · Cited by 2,559
CODATA recommended values of the fundamental physical constants: 2010
Mohr, P. J., Taylor, B. N., & Newell, D. B. (2012) · Reviews of Modern Physics · doi:10.1103/revmodphys.84.1527 · Cited by 2,476
VALD–2: Progress of the Vienna Atomic Line Data Base
Kupka, F., Piskunov, N. E., Ryabchikova, T. A., Stempels, H. C., & Weiss, W. W. (1999) · Astronomy & Astrophysics Supplement Series · doi:10.1051/aas:1999267 · Cited by 1,572
Quantum Mechanics of One- and Two-Electron Atoms
Bethe, H. A., & Salpeter, E. E. (1977) · Springer eBooks · doi:10.1007/978-1-4613-4104-8 · Cited by 1,288
Edlén, B. (1966) · Metrologia · doi:10.1088/0026-1394/2/2/002 · Cited by 1,263
The fundamental constants and their variation: observational and theoretical status
Uzan, J. (2003) · Reviews of Modern Physics · doi:10.1103/revmodphys.75.403 · Cited by 1,214
Research works printed but not linked: 8
- Bahcall J.N., 2003, ApJ
- Bekenstein J.D., 1979, Comment. Astrophys., 8, 89
- J.C. Berengut, V.A. Dzuba, and V.V. Flambaum , 2003 , Phys. Rev. A , accepted (physics/0305068) · arXiv
- F.J. Dyson, A. Salam, and E.P. Wigner , 1972 , in, eds, Aspects of Quantum Theory . Cambridge Univ. Press, Cambridge, p. 213
- Jenniskens P., 1994, A&AS, 106, 39
- Martins C.J.A.P., 2003, Phys. Rev. Lett.
- Piskunov N.E., 1995, A&AS, 112, 525
- Varshalovich D.A., 1996, Astron. Lett., 22, 6
Cited by
Sorted by citations
Planck 2013 results. XVI. Cosmological parameters
Ade, P. A. R., Aghanim, N., Armitage-Caplan, C., Arnaud, M., Ashdown, M., Atrio-Barandela, F., Aumont, J., Baccigalupi, C., Banday, A. J., Barreiro, R. B., et al. (2014) · Astronomy and Astrophysics · doi:10.1051/0004-6361/201321591 · Cited by 8,459
Copeland, E. J., Sami, M., & Tsujikawa, S. (2006) · International Journal of Modern Physics D · doi:10.1142/s021827180600942x · Cited by 6,733
Nobel Lecture: Passion for precision
Hänsch, T. W. (2006) · Reviews of Modern Physics · doi:10.1103/revmodphys.78.1297 · Cited by 913
Challenges for Λ CDM: An update
Perivolaropoulos, L., & Skara, F. (2022) · New Astronomy Reviews · doi:10.1016/j.newar.2022.101659 · Cited by 1,130
Douglas, M. R., & Kachru, S. (2007) · Reviews of Modern Physics · doi:10.1103/revmodphys.79.733 · Cited by 1,122
Metadata
- Authors
- Murphy, M. T., Webb, J. K., & Flambaum, V. V.
- Affiliations
- University of Cambridge (GB)
- UNSW Sydney (AU)
- Corresponding author
- Murphy, M. T.
- Webb, J. K.
- Venue
- Monthly Notices of the Royal Astronomical Society
- Publisher
- Oxford University Press (OUP)
- Published
- 2003-10
- Volume
- 345
- Issue
- 2
- Pages
- 609-638
- ISSN
- 0035-8711 (ISSN-L)
- 1365-2966
- OpenAlex
- W2153130534
- Cited by
- 514
- References
- 115
- Citations by year
- 2026: 3 · 2025: 8 · 2024: 8 · 2023: 16 · 2022: 9 · 2021: 12 · 2020: 8 · 2019: 11 · 2018: 11 · 2017: 18 · 2016: 17 · 2015: 21 · 2014: 26 · 2013: 23 · 2012: 27
- FWCI
- 24.68
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Monthly Notices of the Royal Astronomical Society (publishedVersion)
- arXiv (Cornell University) (submittedVersion)
- Figshare (submittedVersion, cc-by)
- Swinburne figshare (Swinburne University of Technology) (submittedVersion)
- arXiv (Cornell University)
- Swinburne figshare (Swinburne University of Technology)
- Funders
- National Aeronautics and Space Administration
- W. M. Keck Foundation
- John Templeton Foundation
- California Institute of Technology
- Topics
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Cosmology and Gravitation Theories
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Galaxies: Formation, Evolution, Phenomena
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Stellar, planetary, and galactic studies
- Keywords
- fine-structure constant variation, alpha variation, quasar absorption lines, systematic errors, two-point correlation function
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
