Does the fine structure constant vary? A detailed investigation into systematic effects
Abstract
We have previously presented 5.7 σ evidence for a smaller αat redshifts 0.2 < zabs < 3.7 from a sample of 128 Keck/HIRES quasar absorption systems: Δα/α = (-0.57 ± 0.10) x10-5. A non-zero <Δα/α manifests itself as a distinct pattern of shifts in the measured absorption line wavelengths. The statistical error is now small: we do detect small line shifts in the HIRES data. Whether these shifts are due to systematic errors or due to real variation in α is now the central question. Here we summarize the two potentially most important systematic effects: atmospheric dispersion and isotopic abundance evolution. Previously, these have been difficult to quantify/model but here we find that neither of them can explain our results. Furthermore, the HIRES spectra themselves contain no evidence for these effects. Independent measurements of Δα/α with a different telescope and spectrograph are now crucial if we are to rule out or confirm the present evidence for a variable α.
- Publication:
-
Astrophysics and Space Science
- Pub Date:
- March 2003
- DOI:
- 10.1023/A:1022570532369
- arXiv:
- arXiv:astro-ph/0210532
- Bibcode:
- 2003Ap&SS.283..577M
- Keywords:
-
- Astrophysics
- E-Print:
- 6 pages, 6 EPS figures. Talk presented at JENAM2002 workshop on The Cosmology of Extra Dimensions and Varying Fundamental Constants. To appear in the proceedings