1. The Axis of Evil: revisited
Kate Land
The Axis of Evil: revisited
astro-ph/ , ,

2. THE ISSUES AXIS OF EVIL Planarity Alignments Low-power Ecliptic issues
OTHER
Asymmetries
Cold spot
27/03/07
The Axis of Evil Revisited Kate Land

3. PLANARITY & AOE
“Intriguingly, both the quadrupole and the octopole are seen to have power suppressed along a particular spatial axis, which lines up between the two, roughly towards (l, b) ~ (-110, 60) in Virgo.”
Tegmark & al.PRD(68)123523
27/03/07
The Axis of Evil Revisited Kate Land

4. A posteriori planarity
Quadrupole
l = 2
m = 2
m = 0
27/03/07
The Axis of Evil Revisited Kate Land

5. A posteriori planarity
Octopole
l = 3
m = 3
m = 1
27/03/07
The Axis of Evil Revisited Kate Land

6. ‘Planarity’ is quite normal -
BUT THE AXIS IS NOT!
27/03/07
The Axis of Evil Revisited Kate Land

7. Axis of Evil Independent of Gaussianity Hard to test 27/03/07
The Axis of Evil Revisited Kate Land

8. Maximum Likelihood Avoid instabilities
Allow model comparison (Bayesian V Freq)
Multipoles share axis, and ratio
27/03/07
The Axis of Evil Revisited Kate Land

9. Models Null ‘Planarity’ l = 2, 3 m = l ‘m-preference’ l = 2 - 5 m free
Parameters:
‘m-preference’ l = m free
Parameters:
27/03/07
The Axis of Evil Revisited Kate Land

10. Maximum Likelihood
27/03/07
The Axis of Evil Revisited Kate Land

11. Significance Compare to simulations Information criteria
‘planarity’ AIC ~ 2, BIC ~ 2.8
‘m-pref’ AIC ~ 2.8, BIC ~ 0
Jeffreys’ scale > 2.5 ‘strong’
27/03/07
The Axis of Evil Revisited Kate Land

12. Bayesian evidence
27/03/07
The Axis of Evil Revisited Kate Land

13. What can we conclude? Evidence for AOE depends on model and method!
Similarly for ns<1 (Liddle astro-ph/ )
Important consequences
Combined with other anomalies
SYSTEMATICS Satellite, data pipeline, …
ASTROPHYSICAL EFFECT Foregrounds, local lensing, …
COSMOLOGICAL FEATURE Non-FLRW models, non-trivial topology, …
27/03/07
The Axis of Evil Revisited Kate Land

14. The Axis of Evil II - Summary
Correlations seen for l = 2,3,4,5
But how do we test the significance?
Propose a model
Frequentist
Bayesian
Planarity
m-preference
27/03/07
The Axis of Evil Revisited Kate Land

15. Priors
27/03/07
The Axis of Evil Revisited Kate Land

16. Axis of Evil ~(260,60) Dipole (264,48) Virgo ~(260,70)
Max asym axis (57,10) Ecliptic pole (96,30) SG pole (47,6)
Cold spot (209,-57)
27/03/07
The Axis of Evil Revisited Kate Land

17. Information criteria
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The Axis of Evil Revisited Kate Land

18. ??
27/03/07
The Axis of Evil Revisited Kate Land