First constraint on cosmological variation of the proton-to-electron mass ratio from two independent telescopes

TL;DR

This study provides a new constraint on the possible variation of the proton-to-electron mass ratio at high redshift by analyzing hydrogen lines from a quasar spectrum, confirming previous results with independent telescopes.

Contribution

First constraint on proton-to-electron mass ratio variation at high redshift using two independent telescopes and consistent analysis methods.

Findings

Constraint of Dmu/mu = (8.5 ± 3.6_{stat} ± 2.2_{syst}) x 10^{-6} at z=2.059

Results agree with previous Keck telescope measurement

Robust absorption line fitting with systematic error consideration

Abstract

A high signal-to-noise spectrum covering the largest number of hydrogen lines (90 H2 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$-$005 with the UVES spectrograph on the ESO Very Large Telescope (Paranal, Chile). This delivers a constraint on a possible variation of the proton-to-electron mass ratio of Dmu/mu = (8.5 \pm 3.6_{stat} \pm 2.2_{syst}) x 10^{-6} at redshift z=2.059$, which agrees well with a recently published result on the same system observed at the Keck telescope yielding Dmu/mu = (5.6 \pm 5.5_{stat} \pm 2.9_{syst}) x 10^{-6}. Both analyses used the same robust absorption line fitting procedures with detailed consideration of systematic errors.