Pulsar Scattering, Lensing and Gravity Waves

Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Pulsar Scattering, Lensing and Gravity Waves Ue-Li Pen, Lindsay King, Latham Boyle CITA Feb 15, 2012 <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Overview IIIIPulsar Scattering VLBI ISM holography, distance measures Enhanced Pulsar Timing Array gravity waves fuzzballs <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Pulsar Scattering IIIIPulsars scintillate strongly due to ISM propagation Lens of geometric size ∼ AU Can be imaged with VLBI (Brisken et al 2010) Deconvolved by interstellar holography (Walker et al 2008) <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Scattering Image Data from Brisken et al, Holographic VLBI. <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary ISM enigma Scattering angle observed mas, 10−8 rad. IIIISnell’s law: sin(θ1)/ sin(θ2) = n2/n1 n − 1 ∼ 10−12 . 4 orders of magnitude mismatch. <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Possibilities IIturbulent ISM: sum of many small scatters. Cannot explain discrete images. confinement problem: super mini dark matter halos, cosmic strings? IIIGeometric alignment: Goldreich and Shridhar (2006) Snell’s law at grazing incidence: ∆α = (1 − n2/n1)/α grazing incidence is geometry preferred at 2-D structures <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Current Sheets IIIIIgeneric outcome of reconnection Pang et al 2010 highly uncertain size, time scale Petschek vs Sweet-Parker long standing controversies <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Gaussian Lens IIIRomani et al 1987, Clegg et al 1998 General highly triaxial system projected into highly elliptical pattern <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Geometry Dds Ds <ul style="display: flex;"><li style="flex:1">~</li><li style="flex:1">~</li><li style="flex:1">~</li><li style="flex:1">~</li><li style="flex:1">~</li><li style="flex:1">~</li></ul>β = θ − αˆ(Ddθ) = θ − α~(θ) ψ(θ) = σθ2κ0 exp(−θ2/2σθ2) <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Plasma lensing qcph = c/ (1 − ωp2/ω2) qωp =nee2/ꢀ0me Φ ≈ ωp2c2/4ω2 critical points and caustics in large convergence limit: ꢀ√ ꢁ eκ0 √θc = ± 1 + ,βc = ± 2κ0 emagnifications: <ul style="display: flex;"><li style="flex:1">−1 </li><li style="flex:1">1</li></ul><ul style="display: flex;"><li style="flex:1">µ = </li><li style="flex:1">,</li></ul>1 + κ0 2 log(−κ0) − 1 <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Time light curves <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Time light curves <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Fiedler Event 2.7 and 8.1 GHz light curves of QSO 0954+658 (Fiedler et al. 1994) <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Holographic Secondary Spectrum <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Pre/post-dictions IIplasma underdensity in current sheets (not generic?) weak (logarithmic) frequency dependence of ESE (Fiedler et al 1987) IIunresolved ESE VLBI image increase during flux decrement (Lazio et al 2000) pulsar inverse parabolic arc cross sections <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Lensing applications IIIIIUse ISM lens as a giant AU scale interferometer! straightforward to resolve the pulsar beam reflex motion. measure pulsar spin axis parallactic angle may be able to resolve pulsar emission region precise pulsar distance measurements <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Pulsar Gravity Wave Observatory IIMajor resolution and sensitivity boost compared to PTA Boyle and Pen 2010: resolution is λ/L, where λ ∼ 10ly and L ∼ 10kly, typically arc minute localization of sources INo longer in source confused limit, able to use pulsar intrinsic GW term IIdistances needed, from the lens distance reconstruction! during ESE, uses two screens to solve all unknowns. <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Black Holes Tests ILai and Rafikov BH reconstruction: not possible to measure spin. IIIIneglects coherent interference between images time delay measured to ∼ ns instead of ∼ms. 10,000 σ spin detection instead of < 1. what are we really testing? Einstein? no alternatives in strong field? <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Fuzzballs IIIIproposed by S. Mathur as alternatives to Black Holes has substantial cult following in stringy community resolves Hawking’s information paradox plausible argument due to failure of no-hair “theorem” <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Hair? Iclassical no-hair: decay of perturbations on dynamical time (ms) IIThermal hair: Boltzman factor supression? 70 exp(−∆E/kT) ∼ exp(−Mc2/kT) ∼ 10−10 : macroscopic excitation most unlikely thing ever considered? (including boltzman brains!) <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Correction Factors Ithermodynamic partition function weights by degeneracy of states: (n1/n2) exp(−(E1 − E2)/kT). IIIIentropy S = log n, proportionate to area cancels the Boltzman factor! round black holes have the least area – least likely state! generic black hole should be fractal, i.e. fuzzball <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Quantum Gravity IStringy interpretation: quantum mechanics is unitary, fuzzball violate Hawking calculation premise IIorder unity deviations near schwarzschild radius deviations fall off as (rs/r)l : unlikely to be tested with accretion flows at ꢀ 2M IIpulsar-BH binary lensing: results in modified or absent fringes! <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Conclusions IPhysics: Underdense current sheets. New input for reconnection plasma studies IIPulsar kinematics: emission region physics, spin axis precise distance measurements: multi-frequency VLBI monitoring of pulsars IIincreased sensitivity coherent precision gravity wave astrometry tests of quantum gravity: need to find inclined BH-PSR binary <ul style="display: flex;"><li style="flex:1">U. Pen </li><li style="flex:1">Pulsar Scattering, Lensing and Gravity Waves </li></ul>

Pulsar Scattering, Lensing and Gravity Waves

Details

Download

Copyright

We respect the copyrights and intellectual property rights of all users. All uploaded documents are either original works of the uploader or authorized works of the rightful owners.

Support