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Jim Cordes & Michael Kramer International SKA Conference 2003 Geraldton 30 July 2003. Pulsar Science with the SKA. Pulsar Science. Extreme matter physics 10x nuclear density High-temperature superfluid & superconductor B ~ B q = 4.4 x 10 13 Gauss Voltage drops ~ 10 12 volts

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Pulsar science with the ska

Jim Cordes& Michael Kramer

International SKA Conference 2003

Geraldton

30 July 2003

Pulsar Science with the SKA

Pulsar Science with the SKA


Pulsar science
Pulsar Science

  • Extreme matter physics

    • 10x nuclear density

    • High-temperature superfluid & superconductor

    • B ~ Bq = 4.4 x 1013 Gauss

    • Voltage drops ~ 1012 volts

    • FEM = 109Fg = 109 x 1011FgEarth

  • Relativistic plasma physics (magnetospheres)

  • Tests of theories of gravity

  • Gravitational wave detectors

  • Probes of turbulent and magnetized ISM (& IGM)

  • End states of stellar evolution

Pulsar Science with the SKA


Why more pulsars
Why more pulsars?

  • Discover rare, extreme objects (odds  Npsr)

    • P < 1 ms P > 8 sec

    • Porb < hours B >> 1013 G (link to magnetars?)

    • V > 1000 km s-1 strange stars?

    • NS-NS and NS-BH binaries, planets

    • Extragalactic pulsars

    • Galactic center pulsars orbiting Sgr A* black hole

Large N  Galactic tomography

  • Large Npsr  Galactic tomography of B + B, ne + ne

    • Branching ratios for compact object formation:

      • NS (normal, isolated)

      • NS (recycled, binaries)

      • NS (magnetar)

      • BH (hypernovae)

      • Strange stars?

Pulsar Science with the SKA


How to do it
How to do it?

  • Find them

  • Time them

  • VLBI them

Pulsar Science with the SKA


Blind surveys with ska
Blind Surveys with SKA

  • (pulsars, transients, ETI)

  • Number of pixels needed to cover FOV: Npix~(bmax/D)2 ~104-109

  • Number of operations Nops~ petaops/s

  • Post processing per beam: e.g. standard pulsar periodicity analysis

    Dedisperse (~1024 trial DM values) + FFT + harmonic sum (+ orbital searches + RFI excision)

  • Requires signal transport of individual antennas to correlator

  • 104 beams needed

    for full-FOV sampling

Pulsar Science with the SKA


Sensitivity calculations
Sensitivity Calculations

  • Pulse smearing effects

    • Dispersive arrival times

    • Scattering

    • Orbital

    • Instrumental

  • Luminosity function for pulsars (> 5 orders of magnitude) = beaming + beam luminosity

  • calculatedusing NE2001

    (Cordes & Lazio 2003)

    Pulsar Science with the SKA


    Pulsar searching with ska vs arecibo
    Pulsar Searching With SKA vs Arecibo

    Dmax = (Lp / Smin1)½Nh¼

    Fourier search

    Nh = # harmonics detectable

    Pulse smearing effects from interstellar scattering

    (also, orbital smearing in NS-BH binaries, etc.)

    Pulsar Science with the SKA


    SKA pulsar survey

    64 s samples

    1024 channels

    600 s per beam

    ~104 psr’s

    Pulsar Science with the SKA


    Summary on pulsar searching
    Summary on Pulsar Searching

    • SKA can perform a Galactic census of neutron stars that will surpass previous surveys by a factor > 10.

    • The discovery space includes exotic objects that provide opportunities for testing fundamental physics.

    • Pulsar searches place particular demands on the ability to do full FOV sampling at high time resolution (64 s) with 1024 channels over > 400 MHz at 1-2 GHz.

    • High frequencies (> 10 GHz) are needed for Galactic center searches to combat scattering.

    • Further simulations are needed that use detailed information from existing pulsar surveys and particular SKA configurations.

    Pulsar Science with the SKA


    Post discovery science

    electron

    distribution

    Magnetic field

    Also: Scintillation 

    Resolving Magnetosphere!

    Post-discovery Science

    Very wide range of applications:

    • Galactic probes:Interstellar medium/magnetic field

    • Star formation history

    • Dynamics, grav. potential

    Pulsar Science with the SKA


    Post discovery science1
    Post-discovery Science

    Very wide range of applications:

    • Galactic probes:Interstellar medium/magnetic field

    • Star formation history

    • Dynamics, grav. potential

    • Extragalactic pulsars:Stellar formation & population, IGM

    Giant pulses

    Extragalactic pulsars

    Probing the local group!

    Pulsar Science with the SKA


    Post discovery science2
    Post-discovery Science

    Very wide range of applications:

    • Galactic probes:Interstellar medium/magnetic field

    • Star formation history

    • Dynamics, grav. potential

    • Extragalactic pulsars:Stellar formation & population, IGM

    • Solid State Physicsunder extreme conditions

    Equation-of-State

    Glitches

    NS structure

    Pulsar Science with the SKA


    Post discovery science3
    Post-discovery Science

    Very wide range of applications:

    • Galactic probes:Interstellar medium/magnetic field

    • Star formation history

    • Dynamics, grav. potential

    • Extragalactic pulsars:Stellar formation & population, IGM

    • Solid State Physicsunder extreme conditions

    • Tests of theories of gravity, e.g. Black Hole properties!

    Pulsar Science with the SKA


    Post discovery science4
    Post-discovery Science

    Very wide range of applications:

    • Galactic probes:Interstellar medium/magnetic field

    • Star formation history

    • Dynamics, grav. potential

    • Extragalactic pulsars:Stellar formation & population, IGM

    • Solid State Physicsunder extreme conditions

    • Tests of theories of gravity, e.g. Black Hole properties!

    • Detection of gravitational wave background

    Pulsar Timing Array:

    Look for global spatial

    pattern in timing residuals!

    Pulsar Science with the SKA


    Gravitational wave background

    Advanced

    LIGO

    Pulsars

    LISA

    Gravitational Wave Background

    • Sources: Binary BHs, Galaxy Formation, Strings, Big Bang

    • Pulsars = Arms of a huge gravitational wave detector

    • Sensitivitycomplementary to LIGO and LISA

    Pulsar Science with the SKA

    Backer (priv. comm)


    Precision pulsar timing with the ska

    Wide bandwidth (20-50%), polarization

    1 s (or even 10-100 ns??)

    Multi-frequency: 400-10000 MHz

    Strong pulsars: stabilization time-scale dominating

    Weak pulsars: SNR dominating

    Multiple FOVs!

    Precision Pulsar Timing with the SKA

    Consider:

    • Fast(!) sampling

    • High sensitivity

    • Systematics, e.g. solar system ephemeredes,

    • time standards

    • Interstellar weather

    • Multipath scattering

    • Timing noise (?)

    • Profile stability

    Pulsar Science with the SKA


    Multiple fovs initial simulation results

    Independent FOVs:

    About 12,000 pulsars, ~1300 MSPs

    Sources (=beams) per FOV

    Multiple FOVs:Initial Simulation Results

    Simulated Population:

    Pulsar Science with the SKA


    Multiple FOVs:Initial Simulation Results

    Simulated Population:

    Required time for one(!) timing point:

    All Pulsars

    Pulsar Science with the SKA


    Multiple fovs initial simulation results1
    Multiple FOVs:Initial Simulation Results

    Simulated Population:

    Required time for one(!) timing point:

    Millisecond Pulsars

    Pulsar Science with the SKA


    Summary pulsars with the ska
    Summary:Pulsars with the SKA

    • Overwhelming science case:

    • New quality due to both leap in numbers and timing precision

    • “Modest” frequency coverage but large bandwidth

    • Large number of simultaneous beams/FOVs desirable

    • Detailed requirements different for searching & timing

    • - both modes are necessary to obtain science!!

    • Configuration: sensitive core but with very large baselines

    • (to enable astrometry out to 10 kpc)

    • Significant post-processing requirements!

    • Large instantaneous  at 2 GHz

      • (contiguous or separated FOVs)

    • searching: 50 s sampling full FOV

    • timing: 1 s sampling pencil beam

    • capability of  up to 10 to 15 GHz

    • (less than 1 SKA)

     Hybrid Design:

    Pulsar Science with the SKA


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