Pulsar Scattering, Lensing and Gravity Waves

Introduction Convergent Plasma Lenses Gravity Waves Black Holes/Fuzzballs Summary

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~ˆ(D θ~) = θ~ − ~α(θ~) Ds d 2 2 2 ψ(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 − ωp/ω ) q 2 ωp = ne e /0me 2 2 2 Φ ≈ ωpc /4ω critical points and caustics in large convergence limit: √ e κ0 θc = ± 1 + , βc = ±√ 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 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