1. A new result on space- time variation of α – part B Julian King (UNSW) Collaborators: John Webb (UNSW), Victor Flambaum (UNSW) Michael Murphy (Swinburne) Bob Carswell (IOA Cambridge) …and others

2. The previous status of α Δα/α (10 -5 ) Current largest sample of quasar absorber constraints on Δα/α come from Murphy et al (2004) from Keck/HIRES Found that Δα/α = ( -0.57 ± 0.11 ) x 10 -5 Effect larger at z>1 ?? Obvious question: what would a different telescope find?

3. The VLT sample The goal: To use archive spectra from UVES (Ultraviolet and Visual Echelle Spectrograph) on the VLT in Chile to try to confirm (or dispute) the Keck results The method: In the same manner as the previous Keck results, we fit Voigt profiles to the quasar profiles and determine Δα/α We derive a sample of 153 final quasar absorbers = 153 x Δα/α We have verified that our uncertainties are correct using Markov Chain Monte Carlo methods Other improvements in technique (Levenberg-Marquardt algorithm, determining number of components using Akaike Information Criterion, robust statistical methods)

4. Δα/α vs redshift – VLT sample Weighted mean: Δα/α = (0.23 ± 0.12) x 10 -5 (after increasing error bars to account for χ 2 ν =1.78) compare with Murphy et al (2004): Δα/α = (-0.57 ± 0.11) x 10 -5 Error bars increased by  0.9 x 10 -5

5. Δα/α vs redshift – comparison with Keck VLT + Keck Keck VLT

6. VLT – Correlation with declination? Declination is equivalent to latitude 2.1σ correlation

7. Correlation with declination after adding in Keck data VLT Keck

8. Δα/α data for different sightlines

9. 4.1σ evidence for a Δα/α dipole from VLT + Keck Δα/α = c + A cos(θ)

10. The Keck & VLT dipoles point in the same direction VLTKeckCombined 20 degrees p = 0.05

11. Low and high redshift cuts are consistent in direction......but the effect is larger at high redshift... z > 1.6z < 1.6Combined

12. ...so add in a simple time relationship Δα/α = c + A t cos(θ) 4.1σ evidence

13. What next? Although the results appear consistent, important to look for systematics (next talk!) And of course... More observations!

14. Could increase signal through high-declination observations