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Improved constraints on possible variation of physical constants from H I 21cm and molecular QSO absorption lines | | M. T. Murphy
; J. K. Webb
; V. V. Flambaum
; M. J. Drinkwater
; F. Combes
; T. Wiklind
; | | Date: |
29 Dec 2000 | | Journal: | Mon.Not.Roy.Astron.Soc. 327 (2001) 1244 | | Subject: | astro-ph | | Affiliation: | UNSW), J. K. Webb (UNSW), V. V. Flambaum (UNSW), M. J. Drinkwater (UMelb), F. Combes (Paris Obs.), T. Wiklind (OSO | | Abstract: | QSO absorption spectra provide an extremely useful probe of possible cosmological variation in various physical constants. Comparison of H I 21cm absorption with corresponding molecular (rotational) absorption spectra allows us to constrain variation in y=alpha^2*g_p where alpha is the fine structure constant and g_p is the proton g-factor. We analyse spectra of two QSOs, PKS 1413+135 and TXS 0218+357, and derive values of dy/y at absorption redshifts of z=0.2467 and 0.6847 by simultaneous fitting of the H I 21cm and molecular lines. We find dy/y=(-0.20 +/- 0.44)*10^{-5} and dy/y=(-0.16 +/- 0.54)*10^{-5} respectively, indicating an insignificantly smaller y in the past. We compare our results with other recent constraints from the same two QSOs (Drinkwater et al. 1998; Carilli et al. 2000) and with our recent optical constraints which indicated a smaller alpha at higher redshifts. | | Source: | arXiv, astro-ph/0101519 | | Services: | Forum | Review | PDF | Favorites | |
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