First measurement of Mg isotope abundances at high redshifts and accurate estimate of Delta alpha/alpha

Understand

(Abridged) We use a high-resolution spectrum of the quasar HE0001-2340 observed with the UVES/VLT to measure Mg isotope abundances in the intervening absorption-line systems at high redshifts.

• Line profiles are prepared accounting for possible shifts between the individual exposures.
• Due to unique composition of the selected systems - the presence of several transitions of the same ion - we can test the local accuracy of the wavelength scale calibration which is the main source of errors in the sub-pixel line position measurements.
• In the system at zabs = 0.45 which is probably a fragment of the outflow caused by SN Ia explosion of high-metallicity white dwarf(s) we measured velocity shifts of MgII and MgI lines relative to other lines (FeI, FeII, CaI, CaII): Delta V(MgII) = -0.44 +/- 0.05 km/s and Delta V(MgI) = -0.17 +/- 0.17$ km/s.