Open AccessNew limits on the possible variation of physical constants
Author(s) -
Drinkwater M.J.,
Webb J.K.,
Barrow J.D.,
Flambaum V.V.
Publication year - 1998
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1998.2952457.x
Subject(s) - physics , quasar , redshift , astrophysics , variation (astronomy) , physical constant , universe , astronomy , spectral line , absorption spectroscopy , galaxy , optics , quantum mechanics
Recent detections of high‐redshift absorption by both atomic hydrogen and molecular gas in the radio spectra of quasars have provided a powerful tool for measuring possible temporal and spatial variations of physical ‘constants’ in the universe. We compare the frequency of high‐redshift hydrogen 21‐cm absorption with that of associated molecular absorption in two quasars to place new (1σ) upper limits on any variation in y≡g p α 2 (where α is the fine‐structure constant, and g p is the proton g ‐factor of at redshifts z = 0.25 and 0.68. These quasars are separated by a comoving distance of 3000 Mpc ( H 0 = 75 km s −1 Mpc −1 and q 0 ). We also derive limits on the time rates of change and between the present epoch and z = 0.68. These limits are more than an order of magnitude smaller than previous results derived from high‐redshift measurements.