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2007MNRAS.374..634T - Mon. Not. R. Astron. Soc., 374, 634-646 (2007/January-2)
Probing variations in fundamental constants with radio and optical quasar absorption-line observations.
TZANAVARIS P., MURPHY M.T., WEBB J.K., FLAMBAUM V.V. and CURRAN S.J.
Abstract (from CDS):
Combining our Δx/x measurement with absorption-line constraints on α-variation yields strong limits on the variation of µ. Our most conservative estimate, obtained by assuming no variations in α or gpis simply Δµ/µ = <Δx/x>weightedtotal. If we use only the four high-redshift absorbers in our sample, we obtain Δµ/µ = (0.58±1.95)x10–5, which agrees (2σ) with recent, more direct estimates from two absorption systems containing molecular hydrogen, also at high redshift, and which have hinted at a possible µ-variation, Δµ/µ = (-2.0±0.6)x10–5. Our method of constraining Δµ/µ is completely independent from the molecular hydrogen observations. If we include the low-redshift systems, our Δµ/µ result differs significantly from the high-redshift molecular hydrogen results. We detect a dipole variation in µ across the sky, but given the sparse angular distribution of quasar sight lines we find that this model is required by the data at only the 88 per cent confidence level. Clearly, much larger samples of 21-cm and molecular hydrogen absorbers are required to adequately resolve the issue of the variation of µ and x.
Abstract Copyright: 2006 The Authors. Journal compilation © 2006 RAS
Journal keyword(s): atomic processes - intergalactic medium - quasars: absorption lines
Simbad objects: 12
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