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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 U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Overview I Pulsar Scattering I VLBI ISM holography, distance measures I Enhanced Pulsar Timing Array gravity waves I fuzzballs U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Pulsar Scattering I Pulsars scintillate strongly due to ISM propagation I Lens of geometric size ∼ AU I Can be imaged with VLBI (Brisken et al 2010) I Deconvolved by interstellar holography (Walker et al 2008) U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Scattering Image Data from Brisken et al, Holographic VLBI. U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary ISM enigma −8 I Scattering angle observed mas, 10 rad. I Snell's law: sin(θ1)= sin(θ2) = n2=n1 −12 I n − 1 ∼ 10 . I 4 orders of magnitude mismatch. U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Possibilities I turbulent ISM: sum of many small scatters. Cannot explain discrete images. I confinement problem: super mini dark matter halos, cosmic strings? I Geometric alignment: Goldreich and Shridhar (2006) I Snell's law at grazing incidence: ∆α = (1 − n2=n1)/α I grazing incidence is geometry preferred at 2-D structures U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Current Sheets I generic outcome of reconnection I Pang et al 2010 I highly uncertain size, time scale I Petschek vs Sweet-Parker I long standing controversies U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Gaussian Lens I Romani et al 1987, Clegg et al 1998 I General highly triaxial system I projected into highly elliptical pattern U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Geometry β~ = θ~ − Dds α~^(D θ~) = θ~ − ~α(θ~) Ds d 2 2 2 (θ) = σθ κ0 exp(−θ =2σθ ) U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Plasma lensing q 2 2 cph = c= (1 − !p=! ) q 2 !p = ne e /0me 2 2 2 Φ ≈ !pc =4! critical points and caustics in large convergence limit: p e κ0 θc = ± 1 + ; βc = ±p 2κ0 e magnifications: −1 1 µ = ; 1 + κ0 2 log(−κ0) − 1 U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Time light curves U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Time light curves U. Pen Pulsar Scattering, Lensing and Gravity Waves 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) U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Holographic Secondary Spectrum U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Pre/post-dictions I plasma underdensity in current sheets (not generic?) I weak (logarithmic) frequency dependence of ESE (Fiedler et al 1987) I unresolved ESE VLBI image increase during flux decrement (Lazio et al 2000) I pulsar inverse parabolic arc cross sections U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Lenses Black Holes/Fuzzballs Summary Lensing applications I Use ISM lens as a giant AU scale interferometer! I straightforward to resolve the pulsar beam reflex motion. I measure pulsar spin axis parallactic angle I may be able to resolve pulsar emission region I precise pulsar distance measurements U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Pulsar Gravity Wave Observatory I Major resolution and sensitivity boost compared to PTA I Boyle and Pen 2010: resolution is λ/L, where λ ∼ 10ly and L ∼ 10kly, typically arc minute localization of sources I No longer in source confused limit, able to use pulsar intrinsic GW term I distances needed, from the lens distance reconstruction! I during ESE, uses two screens to solve all unknowns. U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Black Holes Tests I Lai and Rafikov BH reconstruction: not possible to measure spin. I neglects coherent interference between images I time delay measured to ∼ ns instead of ∼ms. I 10,000 σ spin detection instead of < 1. I what are we really testing? Einstein? no alternatives in strong field? U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Fuzzballs I proposed by S. Mathur as alternatives to Black Holes I has substantial cult following in stringy community I resolves Hawking's information paradox I plausible argument due to failure of no-hair \theorem" U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Hair? I classical no-hair: decay of perturbations on dynamical time (ms) I Thermal hair: Boltzman factor supression? 2 −1070 I exp(−∆E=kT ) ∼ exp(−Mc =kT ) ∼ 10 : macroscopic excitation most unlikely thing ever considered? (including boltzman brains!) U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Correction Factors I thermodynamic partition function weights by degeneracy of states: (n1=n2) exp(−(E1 − E2)=kT ). I entropy S = log n, proportionate to area I cancels the Boltzman factor! I round black holes have the least area { least likely state! I generic black hole should be fractal, i.e. fuzzball U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Quantum Gravity I Stringy interpretation: quantum mechanics is unitary, fuzzball violate Hawking calculation premise I order unity deviations near schwarzschild radius l I deviations fall off as (rs =r) : unlikely to be tested with accretion flows at 2M I pulsar-BH binary lensing: I results in modified or absent fringes! U. Pen Pulsar Scattering, Lensing and Gravity Waves Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary Conclusions I Physics: Underdense current sheets. New input for reconnection plasma studies I Pulsar kinematics: emission region physics, spin axis I precise distance measurements: multi-frequency VLBI monitoring of pulsars I increased sensitivity coherent precision gravity wave astrometry I tests of quantum gravity: need to find inclined BH-PSR binary U. Pen Pulsar Scattering, Lensing and Gravity Waves.
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