A possible dipole in the laws of physics: How ALMA can help

1. A possible dipole in the laws ofphysics:  How ALMA can help John Webb, School of Physics, University of New South Wales, Australia • UNSW team: • Matthew Bainbridge • Julian Berengut • Steve Curran • Victor Flambaum • Julian King • ElliottKoch • AnantTanna • Mike Wilcynzska • John Webb • Angus Wright • Elsewhere: • Bob Carswell(Cambridge) • Michael Murphy (Swinburne) • WimUbachs (Amsterdam)

2. Motivation: This: relies entirely on him plus this Let’s check the basic assumptions to the best of our ability

3. Is the cosmological principle right, or just a very good approximation?

4. Quasars: physics laboratories in the early universe quasar To Earth Lya Lyb SiII CIV SiII CII SiIV Lyman limit Lyaem Lybem NVem Lya forest CIVem SiIVem

5. Exaggerated illustration of how transitions shift in different directions by different amounts – unique pattern First calculated, relativisiticHartree-Fock, 1999. Typicallly ~100<Q<1500

8. α 1999-2004, HIRES/Keck Δα/α (10-5) • Previous largest sample of quasar absorber constraints on Δα/α, Murphy et al (2004), from Keck/HIRES • Δα/α = ( -0.57 ± 0.11 ) x 10-5 • Obvious question: what would a different telescope find?

9. α2011: Comparing new UVES/VLT data with Keck VLT + Keck Keck VLT Keck VLT

10. Different patterns in different directions Looking “North” Lines on Earth Redshifted lines Looking “South” Looks pretty shifty…

11. 4.1σ departure from α=constant (variable) Δα/α = c + A cos(θ)

12. Keck & VLT dipoles independently agree, p=4% VLT Keck Combined

13. Low and high redshift cuts are consistent in direction. Effect is larger at high redshift. z > 1.6 z < 1.6 Combined

14. Distance dependence ∆α/αvsBrcosΘ for the model ∆α/α=BrcosΘ+m showing the gradient in α along the best-fit dipole. The best- fit direction is at right ascension 17.4 ± 0.6 hours, declination −62 ± 6 degrees, for which B = (1.1 ± 0.2) × 10−6 GLyr−1 and m = (−1.9 ± 0.8) × 10−6. This dipole+monopole model is statistically preferred over a monopole-only model also at the 4.1σ level. A cosmology with parameters (H0 , ΩM , ΩΛ ) = (70.5, 0.2736, 0.726).

15. Are a few high S/N outliers responsible for the signal, by chance? • Alternative to growing error bars • Robustness check – iterative trimming • Adopt statistical-only errors and iteratively clip most deviant point • How much data do we need to discard to remove the dipole? • c2n = 1 reached when ~10% clipped • Dipole significance ~5.5sat c2n = 1 • Dipole significance stays above 3s until ~60% of data discarded

16. Two internal consistencies: Keck and VLT dipoles agree. Independent samples, different data reduction procedures, different instruments and telescopes. High and low redshiftdipoles also agree - different species used at low and high redshift – and different transitions respond differently to the same change in a. Other suggestive points: Scatter in data exceeds statistical-only error bars (expected). Keeping all points and growing errors is conservative. Trimming increases significance and shows signal is present in the majority or all of the data. Monopole. Predominant in Keck. Mg isotopes? Early enrichment by very massive stars? Hints that this result might be real

17. How can ALMA help? • High-z sub-mm galaxies • Radio lines very sensitive to e.g. • Strong CI and CO and other lines • Select gravitationally lensed objects and pick out individual massive molecular cores • Minimiseradiative transfer effects, line offsets (carbon isotopes?) • Statistical sample to randomise residual species offsets