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First cosmological constraints on the proton-to-electron massc ratio from observations of rotational transitions of methanol
journal contribution
posted on 2023-05-17, 12:29 authored by Simon EllingsenSimon Ellingsen, Voronkov, MA, Breen, SL, James LovellJames LovellWe have used the Australia Telescope Compact Array to measure the absorption from the 20 → 3–1E 12.2 GHz transition of methanol toward the z = 0.89 lensing galaxy in the PKS B1830–211 gravitational lens system. Comparison of the velocity of the main absorption feature with the published absorption spectrum from the 10 → 2–1E transition of methanol shows that they differ by –0.6 ± 1.6 km s–1. We can use these observations to constrain the changes in the proton-to-electron mass ratio μ from z = 0.89 to the present to 0.8 ± 2.1 × 10–7. This result is consistent, and of similar precision to recent observations at z = 0.68 achieved through comparison of a variety of rotational and inversion transitions, and approximately a factor of two better than previous constraints obtained in this source. Future more sensitive observations that incorporate additional rotational methanol transitions offer the prospect of improving current results by a factor of 5-10.
History
Publication title
Astrophysical Journal LettersVolume
747Article number
L7Number
L7Pagination
1-5ISSN
2041-8205Department/School
School of Natural SciencesPublisher
Institute of Physics Publishing Ltd.Place of publication
United KingdomRights statement
Copyright 2012 The American Astronomical Society.Repository Status
- Restricted