Further constraints on variation of the fine-structure constant from alkali-doublet QSO absorption lines |
| |
| Authors: | MT Murphy JK Webb VV Flambaum JX Prochaska AM Wolfe |
| |
| Institution: | 1School of Physics, The University of New South Wales, UNSW Sydney, NSW 2052, Australia;2The Observatories of the Carnegie Institute of Washington, 813 Santa Barbara St., Pasadena, CA 91101, USA;3Department of Physics and Center for Astrophysics and Space Sciences, University of California, San Diego, C-0424, La Jolla, CA 920923, USA |
| |
| Abstract: | Comparison of quasar (QSO) absorption-line spectra with laboratory spectra provides a precise probe for variability of the fine-structure constant, α , over cosmological time-scales. We constrain variation in α in 21 Keck/HIRES Si iv absorption systems using the alkali-doublet (AD) method in which changes in α are related to changes in the doublet spacing. The precision obtained with the AD method has been increased by a factor of 3:  . We also analyse potential systematic errors in this result. Finally, we compare the AD method with the many-multiplet method, which has achieved an order of magnitude greater precision, and we discuss the future of the AD method. |
| |
| Keywords: | atomic data line: profiles techniques: spectroscopic quasars: absorption lines ultraviolet: general |
|
|
