Abstract
Aims.Verification the theoretical prediction of oscillation of the fine-structure constant over cosmic time requires high precision measurements at individual redshifts. In earlier studies the mean values averaged over wide redshift intervals were usually reported. This requirement can be met using the single ion differential α measurement (SIDAM) procedure. We apply SIDAM to the lines associated with the damped Lyα system observed at zabs = 1.15 in the spectrum of HE 0515–4414. Methods.The spectrum was obtained by means of the UV-Visual Echelle Spectrograph (UVES) at the ESO Very Large Telescope (VLT). Results.The weighted mean calculated using carefully selected 34 pairs (, and 2586 Å) is ( C.L.). The precision of this estimate improves by a factor of 2 the previous one reported for the same system. The obtained result represents an absolute improvement with respect to what has been done in the measurements of .
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
