Journal Article

Constraint on a variation of the proton-to-electron mass ratio from H<sub>2</sub> absorption towards quasar Q2348−011

Julija Bagdonaite, Michael T. Murphy, Lex Kaper and Wim Ubachs

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 421, issue 1, pages 419-425
Published in print March 2012 | ISSN: 0035-8711
Published online March 2012 | e-ISSN: 1365-2966 | DOI:
Constraint on a variation of the proton-to-electron mass ratio from H2 absorption towards quasar Q2348−011

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Molecular hydrogen (H2) absorption features observed in the line of sight to Q2348−011 at redshift zabs≃ 2.426 are analysed for the purpose of detecting a possible variation of the proton-to-electron mass ratio μ≡mp/me. By its structure, Q2348−011 is the most complex analysed H2 absorption system at high redshift so far, featuring at least seven distinctly visible molecular velocity components. The multiple velocity components associated with each transition of H2 were modelled simultaneously by means of a comprehensive fitting method. The fiducial model resulted in Δμ/μ= (−0.68 ± 2.78) × 10−5, showing no sign that μ in this particular absorber is different from its current laboratory value. Although not as tight a constraint as other absorbers have recently provided, this result is consistent with the results from all previously analysed H2-bearing sightlines. Combining all such measurements yields a constraint of |Δμ/μ|≤ 10−5 for the redshift range z= 2–3.

Keywords: methods: data analysis; quasars: absorption lines; cosmology: observations

Journal Article.  4525 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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