CONSTRAINING FUNDAMENTAL CONSTANT EVOLUTION WITH H I AND OH LINES

We report deep Green Bank Telescope spectroscopy in the redshifted HI 21 cm and OH 18 cm lines from the z = 0.765 absorption system toward PMN J0134-0931. A comparison between the "satellite" OH 18 cm line redshifts, or between the redshifts of the HI 21 cm and "main" OH 18 cm li...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2012-02, Vol.746 (2), p.1-5
Main Authors: Kanekar, N, Langston, G I, Stocke, J T, Carilli, C L, Menten, K M
Format: Article
Language:English
Subjects:
ABSORPTION
ASTROPHYSICS
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
CARBON MONOXIDE
COMPARATIVE EVALUATIONS
Conjugates
Constants
Constraining
ELECTRONS
Evolution
FINE STRUCTURE
FUNDAMENTAL CONSTANTS
GALAXIES
HYDROGEN 1
LANDE FACTOR
Line shape
MHZ RANGE
PROTONS
QUASARS
RED SHIFT
REST MASS
SATELLITES
SPECTROSCOPY
TELESCOPES
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Summary:We report deep Green Bank Telescope spectroscopy in the redshifted HI 21 cm and OH 18 cm lines from the z = 0.765 absorption system toward PMN J0134-0931. A comparison between the "satellite" OH 18 cm line redshifts, or between the redshifts of the HI 21 cm and "main" OH 18 cm lines, is sensitive to changes in different combinations of three fundamental constants, the fine structure constant alpha , the proton-electron mass ratio mu = m sub(p)/m sub(e), and the proton g-factor g sub(p). We find that the satellite OH 18 cm lines are not perfectly conjugate, with both different line shapes and stronger 1612 MHz absorption than 1720 MHz emission. This implies that the satellite lines of this absorber are not suitable to probe fundamental constant evolution. A comparison between the redshifts of the HI 21 cm and OH 18 cm lines, via a multi-Gaussian fit, yields the strong constraint [ Delta F/F] = [-5.2 + or - 4.3] x 10 super(-6), where F = g sub(p)[ mu alpha super(2)] super(1.57) and the error budget includes contributions from both statistical and systematic errors. We thus find no evidence for a change in the constants between z = 0.765 and the present epoch. Incorporating the constraint [ Delta mu / mu ] < 3.6 x 10 super(-7) from another absorber at a similar redshift and assuming that fractional changes in g sub(p) are much smaller than those in alpha , we obtain [ Delta alpha / alpha ] = (-1.7 + or - 1.4) x 10 super(-6) over a look-back time of 6.7 Gyr.
ISSN:2041-8205
2041-8213
DOI:10.1088/2041-8205/746/2/L16