The BullsEye Effect in 3D

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The Bulls-Eye Effect in 3D

• Elizabeth Praton
• Franklin Marshall College
• 8/12/2005

Run this in slide show mode.
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3-D Numerical Simulation

• The following slide shows a mock
  magnitude-limited galaxy survey.
• Observer is at simulation center, taking slices
  bounded by constant latitude.
• Polar plots show longitude vs. distance
  (real-space) and longitude vs. velocity
  (redshift-space).
• Animation shows effect of increasing slice
  thicknesswatch how pattern changes.

Simulation Information
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Simulation Information

• 3-D numerical simulation of gravitational
  clustering (Melott Shandarin 1993).
• Initial power spectrum P(k) kn, n 0.
• Periodic boundary conditions.
• Number of points (128)3.

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3D Simulation, thick slices
Mag. Limit m lt 17
Praton, Melott, Peterson 1997
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Survey Data

• The next two slides show results from the CfA
  redshift survey.
• Our view in the Zone of Avoidance is blocked by
  our galaxys dusty disk.
• Slides show result of increasing slice thickness.

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CfA Survey
mag. limit b lt 15.5
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CfA Survey, thick slices
b lt 15.5
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Conclusions

• The bulls-eye pattern gets stronger with
  increasing slice thickness in both simulation and
  survey data.
• This occurs because thicker slices contain more
  complete filaments than thinner slices.

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References

• Marzke, R.O., Huchra, J.P., Geller, M.J. 1996,
  Large-scale structure at low galactic latitude,
  AJ, 112, 1803.
• Melott, A.L. Shandarin, S.F. 1993, Controlled
  experiments in gravitational clustering, ApJ,
  410, 469.
• Praton, E.A., Melott, A. L., Peterson, S.A.
  1997, Further investigations of the bulls-eye
  effect, BAAS, 29, 1353.