Mid- and far-infrared fine-structure line sensitivities to hypothetical variability of the fine-structure constant

Abstract

Sensitivity coefficients to temporal variation of the fine-structure constant alpha for transitions between the fine-structure (FS) sub-levels of the ground states of C I, Si I, S I, Ti I, Fe I, N II, Fe II, O III, S III, Ar III, Fe III, Mg V, Ca V, Na VI, Fe VI, Mg VII, Si VII, Ca VII, Fe VII, and Si IX are calculated. These transitions lie in the mid- and far-infrared regions and can be observed in spectra of high-redshift quasars and infrared bright galaxies with active galactic nuclei. Using FS transitions to study alpha-variation over cosmological timescale allows to improve the limit on $|\Delta \alpha /\alpha |$ by several times as compared to contemporaneous optical observations ($|\Delta \alpha /\alpha |<10^{-5}$), and to suppress considerably systematic errors of the radial velocity measurements caused by the Doppler noise. Moreover, the far infrared lines can be observed at redshifts z > 10, far beyond the range accessible to optical observations (z < 4). We have derived a simple analytical expression which relates the FS intervals and the sensitivity of the FS transitions to the change of alpha.

RevTeX4, 7 pages, submitted to PRA; v2: results for light ions (Z<10) have changed

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Cited by in corpus (2)

• Transition frequency shifts with fine-structure constant variation for Fe I. Isotope shift calculations in Fe I and Fe II
• Sensitivity coefficients to $\alpha$-variation for fine-structure transitions in Carbon-like ions