title: First constraint on cosmological variation of the proton-to-electron mass ratio from two independent telescopes.
abstract: A high signal-to-noise spectrum covering the largest number of hydrogen lines (90 H(2) lines and 6 HD lines) in a high-redshift object was analyzed from an observation along the sight line to the bright quasar source J2123-005 with the Ultraviolet and Visual Echelle Spectrograph on the European Southern Observatory Very Large Telescope (Paranal, Chile). This delivers a constraint on a possible variation of the proton-to-electron mass ratio of Δμ/μ=(8.5 ± 3.6(stat) ± 2.2(syst))×10(-6) at redshift z(abs) = 2.059, which agrees well with a recently published result on the same system observed at the Keck telescope yielding Δμ/μ=(5.6 ± 5.5(stat) ± 2.9(syst))×10(-6). Both analyses used the same robust absorption line fitting procedures with detailed consideration of systematic errors.
authors.affiliation: Institute for Lasers, Life and Biophotonics, VU University Amsterdam, The Netherlands.
authors.forename: F
authors.initials: F
authors.lastname: van Weerdenburg
authors.forename: M T
authors.initials: MT
authors.lastname: Murphy
authors.forename: A L
authors.initials: AL
authors.lastname: Malec
authors.forename: L
authors.initials: L
authors.lastname: Kaper
authors.forename: W
authors.initials: W
authors.lastname: Ubachs