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New constraint on cosmological variation of the proton-to-electron mass ratio from Q0528−250

Authors

  • Julian A. King,

    Corresponding author
    1. School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
    2. Department of Physics and Astronomy, LaserLaB, VU University, De Boelelaan 1081, 1081 HV Amsterdam, the Netherlands
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  • Michael T. Murphy,

    Corresponding author
    1. Centre for Astrophysics and Supercomputing, Swinburne University of Technology, VIC 3122, Australia
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  • Wim Ubachs,

    Corresponding author
    1. Department of Physics and Astronomy, LaserLaB, VU University, De Boelelaan 1081, 1081 HV Amsterdam, the Netherlands
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  • John K. Webb

    Corresponding author
    1. School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
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E-mail: jking.phys@gmail.com (JAK); mmurphy@swin.edu.au (MTM); w.m.g.ubachs@vu.nl (WU); jkw@phys.unsw.edu.au (JKW)

ABSTRACT

Molecular hydrogen transitions in quasar spectra can be used to constrain variation in the proton-to-electron mass ratio, μ≡ mp/me, at high redshifts (z ≳ 2). We present here an analysis of a new spectrum of the quasar Q0528−250, obtained on Very Large Telescope (VLT)/Ultraviolet and Visual Echelle Spectrograph (UVES), and analyse the well-known H2 absorber at z = 2.811 in this spectrum. For the first time we detect deuterated molecular hydrogen (HD) in this system with a column density of log10(N/cm−2) = 13.27 ± 0.07; HD is sensitive to variation in μ, and so we include it in our analysis. Using 76 H2 and seven HD transitions we constrain variation in μ from the current laboratory value to be Δμ/μ= (0.3 ± 3.2stat± 1.9sys) × 10−6, which is consistent with no cosmological variation in μ, as well as with previous results from other H2/HD absorbers. The main sources of systematic uncertainty relate to accurate wavelength calibration of the spectra and the re-dispersion of multiple telescope exposures on to the one pixel grid.

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