SIMBAD references

We assess the cosmological variability of the fine-structure constant α from the analysis of an ensemble of FeII λ1608, λ2344, λ2374, λ2383, λ2587, and λ2600 absorption lines at the redshift z=1.15 toward the QSO HE 0515-4414 by means of the standard many-multiplet (MM) technique and its revision based on linear regression (RMM). This is the first time the MM technique is applied to exceptional high-resolution and high signal-to-noise QSO spectra recorded with the UV-Visual Echelle Spectrograph (UVES) at the ESO Very Large Telescope (VLT). Our analysis results in <Δα/α>_MM=(0.1±1.7)x10^–6 and <Δα/α>_RMM=(-0.4 ±1.9±2.7_sys)x10^–6, which are the most stringent bounds hitherto infered from an individual QSO absorption system. Our results support the null hypothesis <Δα/α≥0 at a significance level of 91 percent, whereas the support for the result <Δα/α≥-5.7x10^–6 presented in former MM studies is 12 percent.