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Laboratory atomic transition data for precise optical quasar absorption spectroscopy

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journal contribution
posted on 2024-07-26, 13:50 authored by Michael MurphyMichael Murphy, J. C. Berengut
Quasar spectra reveal a rich array of important astrophysical information about galaxies which intersect the quasar line of sight. They also enable tests of the variability of fundamental constants over cosmological time- and distance-scales. Key to these endeavours are the laboratory frequencies, isotopic and hyperfine structures of various metal-ion transitions. Here, we review and synthesize the existing information about these quantities for 43 transitions which are important for measuring possible changes in the fine-structure constant, α, using optical quasar spectra, i.e. those of Na, Mg, Al, Si, Ca, Cr, Mn, Fe, Ni and Zn. We also summarize the information currently missing that precludes more transitions being used. We present an up-to-date set of coefficients, q, which define the sensitivity of these transitions to variations in α. New calculations of isotopic structures and q-coefficients are performed for Si II and Ti II, including Si II λ1808 and Ti IIλλ1910.6/1910.9 for the first time. Finally, simulated absorption-line spectra are used to illustrate the systematic errors expected if the isotopic/hyperfine structures are omitted from profile fitting analyses. To ensure transparency, repeatability and currency of the data and calculations, we supply a comprehensive data base as Supporting Information. This will be updated as new measurements and calculations are performed.

Funding

Fundamental physics in distant galaxies

Australian Research Council

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PDF (Published version)

ISSN

0035-8711

Journal title

Monthly Notices of the Royal Astronomical Society

Volume

438

Issue

1

Pagination

23 pp

Publisher

Oxford University Press

Copyright statement

Copyright © 2013 The authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. The published version is reproduced in accordance with the copyright policy of the publisher.

Language

eng

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