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Does the fine structure constant vary?: A detailed investigation into systematic errors With: Chris Churchill (PSU) Victor Flambaum (UNSW) Jason Prochaska.

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Presentation on theme: "Does the fine structure constant vary?: A detailed investigation into systematic errors With: Chris Churchill (PSU) Victor Flambaum (UNSW) Jason Prochaska."— Presentation transcript:

1 Does the fine structure constant vary?: A detailed investigation into systematic errors With: Chris Churchill (PSU) Victor Flambaum (UNSW) Jason Prochaska (UCSC) Wallace Sargent (Caltech) Rob Simcoe (Caltech) John Webb (UNSW) Arthur Wolfe (UCSD)

2 Outline: Systematic errors for the MM method  Detailed analyses: Atmospheric dispersion effects Isotopic ratio evolution  Consistency checks Line removal Other tests for simple, unknown systematics

3 Candidate systematic errors: ? Wavelength calibration errors – JOHN’S TALK ? Instrumental profile variations ? Laboratory wavelength errors (  z =  0 +qx) ? Line blending ? Temperature changes during observations ? Heliocentric velocity variation ? Atmospheric dispersion effects ? Isotopic ratio evolution ? Differential isotopic saturation ? Hyperfine structure effects See Murphy et al., 2001, MNRAS, 327, 1223 for details ? ??

4 Atmospheric dispersion effects:

5 Atmospheric dispersion results: Pre-rotator Post-rotator Rotator

6 Isotopic ratio evolution:

7

8 Isotopic ratio evolution results: Isotope

9 Line removal checks:

10 Removing MgII2796: Post-removal Pre-removal Line Removal

11 Removing MgII2796: Post-removal Pre-removal Line Removal

12 Number of systems where transition(s) can be removed Transition(s) removed Pre-removal Post-removal

13 Other line-removal tests: High-z (1.8 – 3.5) Low-z (0.5 – 1.8) FeII MgI, MgII ZnII CrII FeII Positive Mediocre Anchor Mediocre Negative SiIV

14 Correcting for both systematics: Rotator + Isotope

15 Conclusions:  Main systematics: Atmospheric dispersion Isotopic ratio evolution  Known systematic errors cannot explain results  Nor can simple, unknown systematics  Iodine cell measurements planned for Keck  Independent optical check required: VLT & Subaru  Sleep loss? Future:


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