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Pulsars - History and Morphology

Pulsars - History and Morphology

Presentation for my Astrophysics work in 2013.

It is about neutron stars and pulsares.

Dani Bento

May 24, 2013
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  1. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Pulsars
    History and Morphology
    D. Bento
    Department of Physics
    University of Lisbon - Science Faculty
    Astrophysics, 2013
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  2. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Outline
    Motivation
    The study of Pulsars
    History
    Back to 1932
    Going to the radio survey
    Morphology
    Size, Period and Temperature
    Magnetic Field
    The life sequence of a Pulsar
    Creation and Beyond
    The reborn of a pulsar
    To the Future
    Further Studies
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  3. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    The study of Pulsars
    Outline
    Motivation
    The study of Pulsars
    History
    Back to 1932
    Going to the radio survey
    Morphology
    Size, Period and Temperature
    Magnetic Field
    The life sequence of a Pulsar
    Creation and Beyond
    The reborn of a pulsar
    To the Future
    Further Studies
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  4. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    The study of Pulsars
    What was the question...
    Unknown sources of radio frequencies
    Very accurate pulses
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  5. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    The study of Pulsars
    Precision?
    Figure : Periodic Pulsar Pulses
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  6. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    The study of Pulsars
    It’s a signal of Life or something else?
    No one could say, astronomers didn’t had any theory
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  7. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    The study of Pulsars
    Life?
    Figure : They will be always there...
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  8. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    The study of Pulsars
    Far Away
    Figure : NASA
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  9. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Back to 1932
    Outline
    Motivation
    The study of Pulsars
    History
    Back to 1932
    Going to the radio survey
    Morphology
    Size, Period and Temperature
    Magnetic Field
    The life sequence of a Pulsar
    Creation and Beyond
    The reborn of a pulsar
    To the Future
    Further Studies
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  10. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Back to 1932
    The discovery of the neutron nucleon
    1920 - Ernest
    Rutherford conceived
    the possible existence
    of the neutron
    1932 - James Chadwick
    discovered it
    Figure : Proton vs Neutron
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  11. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Back to 1932
    The model of a neutron star
    1934 - Walter Baade and
    Fritz Zwicky proposed their
    existence
    Collapsed supernovae
    Small Radius: 20km
    Dense: 5 × 1017km/m3
    Hot: T ∼ 1011K
    Magnetic Field: 1017G
    Figure : Neutron Star
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  12. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Going to the radio survey
    Outline
    Motivation
    The study of Pulsars
    History
    Back to 1932
    Going to the radio survey
    Morphology
    Size, Period and Temperature
    Magnetic Field
    The life sequence of a Pulsar
    Creation and Beyond
    The reborn of a pulsar
    To the Future
    Further Studies
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  13. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Going to the radio survey
    The first pulsar record
    1967 - Jocelyn Bell found this strange pulses at 81.5MHz
    Figure : The first record of a pulsar by Jocelyn Bell
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  14. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Going to the radio survey
    Theories and explanations needed
    It was NOT life: They are found all around
    Figure : Milky Way’s galactic plane
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  15. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Going to the radio survey
    Theories and explanations needed
    It was NOT a Normal Star: It doesn’t pulse
    Figure : Milky Way’s galactic plane radio emission
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  16. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Going to the radio survey
    Theories and explanations needed
    It was NOT an Eclipsing Binary: Impossible
    Figure : Binary System
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  17. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Going to the radio survey
    Theories and explanations needed
    It was NOT a Variable Star: They have Big Periods
    Figure : Cepheid’s Luminosity Evolution
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  18. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Going to the radio survey
    Bringing some old and unused proposals
    Figure : Crab Nebula’s pulsar
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  19. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Size, Period and Temperature
    Outline
    Motivation
    The study of Pulsars
    History
    Back to 1932
    Going to the radio survey
    Morphology
    Size, Period and Temperature
    Magnetic Field
    The life sequence of a Pulsar
    Creation and Beyond
    The reborn of a pulsar
    To the Future
    Further Studies
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  20. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Size, Period and Temperature
    Size and Temperature
    Figure : Pulsar size compared with Manhattan Island
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  21. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Magnetic Field
    Outline
    Motivation
    The study of Pulsars
    History
    Back to 1932
    Going to the radio survey
    Morphology
    Size, Period and Temperature
    Magnetic Field
    The life sequence of a Pulsar
    Creation and Beyond
    The reborn of a pulsar
    To the Future
    Further Studies
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  22. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Magnetic Field
    Magnetic Field
    Figure : Magnetic field lines
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  23. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Magnetic Field
    The basic origin of the B field
    Using hidrostatic equilibrium we found that P ∼ ρ5
    3
    So, for the neutron star we have
    R =
    1
    M 1
    3 mnµ
    5
    3
    n
    (1)
    The original magnetic flux is maintained after the colapse,
    so:
    Bns ≈ Bwd (
    Rwd
    Rns
    )2 = 1.3 × 1010T (2)
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  24. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Magnetic Field
    The basic origin of the B field
    Using hidrostatic equilibrium we found that P ∼ ρ5
    3
    So, for the neutron star we have
    R =
    1
    M 1
    3 mnµ
    5
    3
    n
    (1)
    The original magnetic flux is maintained after the colapse,
    so:
    Bns ≈ Bwd (
    Rwd
    Rns
    )2 = 1.3 × 1010T (2)
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  25. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Magnetic Field
    The basic origin of the B field
    Using rotational kinetic energy and the equation of energy for a
    magnetic dipole we get:
    B =
    1
    2πR3sin(θ)
    3µ0
    c3IP ˙
    P

    (3)
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  26. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Magnetic Field
    Beam Cone and Light Cylinder
    Cone created by the
    fast rotating star
    Electrons fall in the
    magnetic and electric
    fields like a syncroton
    High polarization
    Figure : Schematic
    representation of a pulsar
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  27. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Creation and Beyond
    Outline
    Motivation
    The study of Pulsars
    History
    Back to 1932
    Going to the radio survey
    Morphology
    Size, Period and Temperature
    Magnetic Field
    The life sequence of a Pulsar
    Creation and Beyond
    The reborn of a pulsar
    To the Future
    Further Studies
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  28. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Creation and Beyond
    How pulsars begin...
    Figure : Star evolution
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  29. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Creation and Beyond
    ... and how they end
    It’s known that the faster pulsars spins the faster they loose
    energy
    ... by neutrino emission
    ... by radiation
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  30. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    The reborn of a pulsar
    Outline
    Motivation
    The study of Pulsars
    History
    Back to 1932
    Going to the radio survey
    Morphology
    Size, Period and Temperature
    Magnetic Field
    The life sequence of a Pulsar
    Creation and Beyond
    The reborn of a pulsar
    To the Future
    Further Studies
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  31. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    The reborn of a pulsar
    Understanding the incoming data
    Super fast pulsars?
    The data doesn’t match with the knowledge about pulsar
    evolution
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  32. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    The reborn of a pulsar
    Binary Stars
    Figure : Binary system with a compact object
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  33. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Further Studies
    Outline
    Motivation
    The study of Pulsars
    History
    Back to 1932
    Going to the radio survey
    Morphology
    Size, Period and Temperature
    Magnetic Field
    The life sequence of a Pulsar
    Creation and Beyond
    The reborn of a pulsar
    To the Future
    Further Studies
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

    View full-size slide

  34. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Further Studies
    Pulsars against General Relativity Theory
    Figure : Project LISA detecting gravitational waves
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  35. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Further Studies
    Pulsars for navigation
    Figure : Artistic view of Rosetta spacecraft guided by pulsars
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  36. Motivation History Morphology The life sequence of a Pulsar To the Future Summary
    Summary
    The are many exotic objects to discover in the Universe.
    A Pulsar put stress tests on all of our Modern Physics
    Theories.
    Hoping a lot of new development on pulsar studies.
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  37. Appendix
    For Further Reading
    For Further Reading I
    Geoff McNamara, Clocks in the Sky - The story of pulsars,
    Springer
    Max Camenzind, Compact Objects in Astrophysics - White
    Drafts, Neutron Stars and Black Holes, Springer
    Werner Becker, Neutron Stars and Pulsares, Springer
    V. S. Beskin, A. V. Gurevich and Ya. N. Istomin Physics of
    the pulsar magnetosphere, Cambridge University Press
    John H. Seiradakis, Richard Wielebinski Morphology and
    Characteristics of Radio Pulsars, Astronomy &
    Astrophysics Review
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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  38. Appendix
    For Further Reading
    For Further Reading II
    A. G. Lyne and D. R. Lorimer Vrije Universiteit, Amsterdam,
    1971-1975
    John Antoniadis et al. A Massive Pulsar in a Compact
    Relativistic Binary, Science 2013
    http://www.atnf.csiro.au/research/pulsar/psrcat/
    Daniel Bento University of Lisbon - Science Faculty
    Pulsars

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