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Radio Interferometry - Simulation and Optimization

Dani Bento
July 01, 2013

Radio Interferometry - Simulation and Optimization

This was my final project on Astronomy and Astrophysics and it was presented in 2013.

I pretended to talk a little about radio astronomy, radio interferometry and how to create a small simulation.

Dani Bento

July 01, 2013
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  1. Motivation Basics Radio-Interferometry Simulator Summary
    Radio-Interferometry
    Simulation and Optimization
    D. Bento
    Department of Physics
    University of Lisbon - Science Faculty
    Astronomy and Astrophysics’s Project, 2013
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  2. Motivation Basics Radio-Interferometry Simulator Summary
    Outline
    Motivation
    Radioastronomy
    Simulation Development
    Basics
    Light and Radiation
    Interference Fenomena
    Radio-Interferometry Simulator
    Concept
    Mathematics
    Fourier Transforms
    UV Projection
    Development and Use
    Results
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  3. Motivation Basics Radio-Interferometry Simulator Summary
    Radioastronomy
    Outline
    Motivation
    Radioastronomy
    Simulation Development
    Basics
    Light and Radiation
    Interference Fenomena
    Radio-Interferometry Simulator
    Concept
    Mathematics
    Fourier Transforms
    UV Projection
    Development and Use
    Results
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  4. Motivation Basics Radio-Interferometry Simulator Summary
    Radioastronomy
    Understand the basics of radioastronomy
    Understand the radio-interferometry technique
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  5. Motivation Basics Radio-Interferometry Simulator Summary
    Simulation Development
    Outline
    Motivation
    Radioastronomy
    Simulation Development
    Basics
    Light and Radiation
    Interference Fenomena
    Radio-Interferometry Simulator
    Concept
    Mathematics
    Fourier Transforms
    UV Projection
    Development and Use
    Results
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  6. Motivation Basics Radio-Interferometry Simulator Summary
    Simulation Development
    Build a virtual radio-interferometry simulator
    Study the optimization aspects for a radio-interferometry
    system
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  7. Motivation Basics Radio-Interferometry Simulator Summary
    Light and Radiation
    Outline
    Motivation
    Radioastronomy
    Simulation Development
    Basics
    Light and Radiation
    Interference Fenomena
    Radio-Interferometry Simulator
    Concept
    Mathematics
    Fourier Transforms
    UV Projection
    Development and Use
    Results
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  8. Motivation Basics Radio-Interferometry Simulator Summary
    Light and Radiation
    Light Spectrum
    visible light is only a small part of all electromagnetic spectrum
    Figure : electromagnetic spectrum
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  9. Motivation Basics Radio-Interferometry Simulator Summary
    Light and Radiation
    Black Body Radiation
    which we can approach radiation emission of all bodies
    Figure : black body radiation (Plank distribution)
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  10. Motivation Basics Radio-Interferometry Simulator Summary
    Interference Fenomena
    Outline
    Motivation
    Radioastronomy
    Simulation Development
    Basics
    Light and Radiation
    Interference Fenomena
    Radio-Interferometry Simulator
    Concept
    Mathematics
    Fourier Transforms
    UV Projection
    Development and Use
    Results
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  11. Motivation Basics Radio-Interferometry Simulator Summary
    Interference Fenomena
    Young’s Double Slit Experiment
    Figure : double slit experiment
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  12. Motivation Basics Radio-Interferometry Simulator Summary
    Interference Fenomena
    Some measures
    Figure : schematic view of 3
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  13. Motivation Basics Radio-Interferometry Simulator Summary
    Interference Fenomena
    We have...
    maxima:
    sin(θ) = mλ, m ∈ Z (1)
    minima:
    sin(θ) = (m + 1/2)λ, m ∈ Z (2)
    λ is the wave length
    if d L we can approach r1 − r2 = dsin(θ)
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  14. Motivation Basics Radio-Interferometry Simulator Summary
    Interference Fenomena
    ... and Observation
    Figure : use of interferogram
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  15. Motivation Basics Radio-Interferometry Simulator Summary
    Concept
    Outline
    Motivation
    Radioastronomy
    Simulation Development
    Basics
    Light and Radiation
    Interference Fenomena
    Radio-Interferometry Simulator
    Concept
    Mathematics
    Fourier Transforms
    UV Projection
    Development and Use
    Results
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  16. Motivation Basics Radio-Interferometry Simulator Summary
    Concept
    Basic Radio Interferometer
    Figure : Schema - b is the distance between antennas, with V1
    and
    V2
    signal and θ is the angle between the source and zenite
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  17. Motivation Basics Radio-Interferometry Simulator Summary
    Concept
    Another view
    Figure : basic radio-interferometer with the base line projection u − v
    The distance between antennas define the maximum angular
    resolution of the system θ = λ/B
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  18. Motivation Basics Radio-Interferometry Simulator Summary
    Mathematics
    Outline
    Motivation
    Radioastronomy
    Simulation Development
    Basics
    Light and Radiation
    Interference Fenomena
    Radio-Interferometry Simulator
    Concept
    Mathematics
    Fourier Transforms
    UV Projection
    Development and Use
    Results
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  19. Motivation Basics Radio-Interferometry Simulator Summary
    Mathematics
    Fourier and Periodic Functions
    F(u, v) =

    −∞

    −∞
    f(x, y)e−i2π(xu+yv)dxdy (3)
    f(x, y) =

    −∞

    −∞
    F(u, v)e−i2π(xu+yv)dudv (4)
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  20. Motivation Basics Radio-Interferometry Simulator Summary
    Mathematics
    Spacial Domain and Frequency Domain
    Figure : 2 dimensional fourier transform
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  21. Motivation Basics Radio-Interferometry Simulator Summary
    Mathematics
    Base line projection
    This is a representation of the u − v plan (time and frequency space)
    Figure : uv plan
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  22. Motivation Basics Radio-Interferometry Simulator Summary
    Mathematics
    Fourier Correlation
    gives a function of geometrical time delay τ in time and
    frequency space
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  23. Motivation Basics Radio-Interferometry Simulator Summary
    Development and Use
    Outline
    Motivation
    Radioastronomy
    Simulation Development
    Basics
    Light and Radiation
    Interference Fenomena
    Radio-Interferometry Simulator
    Concept
    Mathematics
    Fourier Transforms
    UV Projection
    Development and Use
    Results
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  24. Motivation Basics Radio-Interferometry Simulator Summary
    Development and Use
    About the Application
    Development with Python
    Lots of Libraries to use
    Big open source community
    Derived from C Language
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  25. Motivation Basics Radio-Interferometry Simulator Summary
    Development and Use
    Using it...
    Let’s demonstrate it...
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  26. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    Outline
    Motivation
    Radioastronomy
    Simulation Development
    Basics
    Light and Radiation
    Interference Fenomena
    Radio-Interferometry Simulator
    Concept
    Mathematics
    Fourier Transforms
    UV Projection
    Development and Use
    Results
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  27. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    Source Point
    Figure : Simple Source Point
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  28. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    Source Point
    Figure : Radio Galaxy
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  29. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    MERLIN
    Figure : observing source at dec 90o
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  30. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    MERLIN
    Figure : uv plan for source at dec 90o with 3 hours of rotation
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  31. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    MERLIN
    Figure : single point source output
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  32. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    MERLIN
    Figure : single point source CLEAN
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  33. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-A
    Figure : uv plan for source at 90o with no rotation
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  34. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-A
    Figure : uv plan for source at 90o with rotation
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  35. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-A
    Figure : single point source output
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  36. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-A
    Figure : single point source CLEAN
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  37. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-A
    Figure : radio galaxy source output
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  38. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-D
    Figure : uv plan for source at 90o with rotation
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  39. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-D
    Figure : single point source output
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  40. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-D
    Figure : single point source CLEAN
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  41. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-D
    Figure : radio galaxy source output
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  42. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-(A+D)
    Figure : uv plan for source at 90o with rotation
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  43. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-(A+D)
    Figure : radio galaxy source output
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

    View Slide

  44. Motivation Basics Radio-Interferometry Simulator Summary
    Results
    VLA-(A+D)
    Figure : radio galaxy source CLEAN
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  45. Motivation Basics Radio-Interferometry Simulator Summary
    Summary
    The coverage of u − v plan defines the quality of the final
    result
    The length of the base line defines the maximum angular
    resolution
    Primary Beam for each antenna should be included in
    simulation
    New projects are comming with a lot of new science to do
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  46. Appendix
    For Further Reading
    For Further Reading I
    Diane Fisher Miller Basics of Radio Astronomy for the
    Goldstone-Apple Valley Radio Telescope JPL - Advanced
    Mission Operations Section
    Dale E. Gary Introduction to Radio Astronomy NJIT
    Samer Atiani Constructing a Radio Interferometer Faculty
    of Guilford College
    Sándor Frey Radio Interferometry - Brief history, theory &
    practice Institute of Geodesy, Cartography and Remote
    Sensing
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  47. Appendix
    For Further Reading
    For Further Reading II
    Jamie Stevens Interferometry I - Parkes Radio School 2011
    CSIRO
    J. Condon and S. Ransom ITN 215212: Black Hole
    Universe NRAO
    Mike Garrett Radio Astronomy - Basics of radio
    interferometer & Aperture Synthesis MSc. course
    Devaky Kunneriath Introduction to Radio Interferometry
    ALMA
    Hagit Shatkay The Fourier Transform - A Primer
    Department of Computer Science Brown University
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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  48. Appendix
    For Further Reading
    For Further Reading III
    Forrest M. Hoffman An Introduction to Fourier Theroy
    Daniel Bento University of Lisbon - Science Faculty
    Radio-Interferometry

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