Probing the variability of the fine-structure constant 
 with the VLT/UVES

Quast, Ralf; Reimers, D.; Levshakov, S. A.

doi:10.1051/0004-6361:20040013

Cited by 198 publications

(244 citation statements)

References 17 publications

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“…Table I presents calculated values of the parameters q and k MS for the transitions used in astrophysical surveys [2][3][4][5][6]. In order to estimate possible isotope shifts in astrophysics we calculate isotope shifts ⌬ 1,2 for two simple assumptions.…”

Section: Isotopic Effectsmentioning

confidence: 99%

“…On the other hand, the coefficients q and k MS are strongly correlated, and it is impossible to disentangle these two effects. For the lines used in [5], the isotope shifts which correspond to our two limiting cases would imitate the following ␣ variation:…”

Section: · ͑5͒mentioning

confidence: 99%

“…These groups use different data and their results are not fully consistent with each other. In [2][3][4] a nonzero ␣ variation is reported, while [5,6] …”

Section: Introductionmentioning

confidence: 99%

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Space-time variation of the fine-structure constant and evolution of isotope abundances

et al. 2004

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At present several groups are analyzing astrophysical data in a search for the time variation of the finestructure constant ␣. Here we discuss how to exclude systematic effects caused by changes in the isotope abundances during the evolution of the universe. We suggest using particular combinations of the transition frequencies of O II, Al II, Al III, Si II, and Mn II as anchors, which are insensitive to ␣ variation and to changes in isotope abundances. These anchors can be used to determine the cosmological redshift. Then, one can use other combinations of frequencies as probes for the time variation of ␣ and another set as probes for the isotopic abundances. In this way it is possible to eliminate one source of systematic errors in the search for ␣ variation and get more information about evolution of the isotopes. On the level of accuracy that has already been reached in the search for ␣ variation it is possible to see ϳ10% changes in isotope abundances of Si and Ni.

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Section: Isotopic Effectsmentioning

confidence: 99%

Section: · ͑5͒mentioning

confidence: 99%

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Space-time variation of the fine-structure constant and evolution of isotope abundances

et al. 2004

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“…H2, OH, FeII, CH3OH; Thompson 1975;Darling 2003;Chengalur & Kanekar 2003;Quast et al 2004;Jansen et al 2011). The different lines are then likely to arise in the same gas, implying that local velocity offsets should not be a source of systematic effects.…”

Section: Introductionmentioning

confidence: 99%

Constraints on changes in the proton–electron mass ratio using methanol lines

Kanekar

Ubachs

Menten

et al. 2015

Monthly Notices of the Royal Astronomical Society: Letters

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We report Karl G. Jansky Very Large Array (VLA) absorption spectroscopy in four methanol (CH 3 OH) lines in the z = 0.88582 gravitational lens towards PKS1830−211. Three of the four lines have very different sensitivity coefficients K µ to changes in the proton-electron mass ratio µ; a comparison between the line redshifts thus allows us to test for temporal evolution in µ. We obtain a stringent statistical constraint on changes in µ by comparing the redshifted 12.179 GHz and 60.531 GHz lines, [∆µ/µ] 1.1 × 10 −7 (2σ) over 0 < z 0.88582, a factor of ≈ 2.5 more sensitive than the best earlier results. However, the higher signal-to-noise ratio (by a factor of ≈ 2) of the VLA spectrum in the 12.179 GHz transition also indicates that this line has a different shape from that of the other three CH 3 OH lines (at > 4σ significance). The sensitivity of the above result, and that of all earlier CH 3 OH studies, is thus likely to be limited by unknown systematic errors, probably arising due to the frequency-dependent structure of PKS1830−211. A robust result is obtained by combining the three lines at similar frequencies, 48.372, 48.377 and 60.531 GHz, whose line profiles are found to be in good agreement. This yields the 2σ constraint [∆µ/µ] 4 × 10 −7 , the most stringent current constraint on changes in µ. We thus find no evidence for changes in the proton-electron mass ratio over a lookback time of ≈ 7.5 Gyrs.

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“…This 5σ deviation from a non drifting value stimulated further investigation in the field. In 2003-2004 another set of astrophysical data obtained by the Very Large Telescope was analyzed independently using the same approach (Chand et al 2004;Quast et al 2004). The conclusion was that α was stable within | α/α| < 10 −6 in the past.…”

Section: Introductionmentioning

confidence: 99%

Testing the Stability of the Fine Structure Constant in the Laboratory

et al. 2009

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In this review we discuss the progress of the past decade in testing for a possible temporal variation of the fine structure constant α. Advances in atomic sample preparation, laser spectroscopy and optical frequency measurements led to rapid reduction of measurement uncertainties. Eventually laboratory tests became the most sensitive tool to detect a possible variation of α at the present epoch. We explain the methods and technologies that helped to make this possible.

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Probing the variability of the fine-structure constant with the VLT/UVES

Cited by 198 publications

References 17 publications

Space-time variation of the fine-structure constant and evolution of isotope abundances

Space-time variation of the fine-structure constant and evolution of isotope abundances

Constraints on changes in the proton–electron mass ratio using methanol lines

Testing the Stability of the Fine Structure Constant in the Laboratory

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