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Scintillometry

Ue-Li Pen

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Overview

  • Personal history: 2010 Peter Goldreich raises mystery of inverted arclets in secondary spectrum
  • Chris Thompson postulates superconducting cosmic strings
  • Invited myself to Dan’s house over Easter 2015

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Scintillation basics

  • Observe intensity fluctuation dynamic spectrum: frequency-time

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  • ESE

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Sky Image

  • Hengrui reconstructs time series of 2005 Brisken lens
  • Shows 1-D line of primary images, island of second images

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2 screens

  • Liu et al interpretation of Brisken data
  • Two 1-D screens

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Physical challenges

  • Isolated inverted arclets: single distance lens
  • Flux: n_e>1000/cm^3, nkT>10^7, overpressure problem

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Inclined sheet model

  • Reconnection?

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Major potential

  • Precision distances: coherent PTA imaging, neutron moment of inertia
  • Mapping ISM: AU scale structures
  • Theory: Picard-Lefshetz, duality between wave and geometric optics

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Summary

  • Scintillometry pioneers by Dan over decades
  • Recognition of inverted arclets proved disruptive to the previous picture of turbulent scattering
  • Isolated 1-D lensing screens in ISM

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