PULSAR WIND NEBULAE FROM RADIO TO X-RAYS Andrew Melatos (U. Melbourne) 1. Basic PWN physics: shock confinement, wave-like pulsar wind (unique) 2. Radio-to-X-ray diagnostics composition, energy transport, magnetic field geometry WHAT IS A PWN? Bubble of magnetic field and relativistic e Inflated by pulsar, confined by environment Synchrotron source:
centre-filled, highly pold Wind cools adiabatically invisible as far as termination shock Crab nebula (optical) ENVIRONMENTAL ZOO Vela SNR Like Crab, but older (Helfand et al. 01) Black Widow binary
H+ X-ray shocks Wind ablates companion Guitar nebula (Gaensler et al. 03) H bow shock PSR speeding through ISM (Chatterjee & Cordes 03) FLARES FROM PSR B1259-63 Eccentric binary PSR Splashes into Be stars disk eclipse Pulsed radio DM, RM
density, B field Unpulsed radio & X-ray shock physics transient mini-PWN (Connors et al. 02) radio eclipse 1.4 GHz TERMINATION SHOCK PSR wind ram pressure P L/4r2c
termination shock SN remnant + filaments backwash confined by SNR P Lage/(4r3/3) blast wave Reverse shock: contracts as backwash accumulates
WAVE-LIKE WIND Jdisp E r-1 Jcond n r-2 circular poln (helix) linear poln (stripes) Jdisp > Jcond for r > 105rLC current sheet
Global plasma wave oscillating at CROSSBOW MORPHOLOGY (Hester et al. 02) Chandra (X-ray) HST (optical) Torus (wisps) + jet (knots) vary daily Gemini
(near-IR) mHz variability in near IR: Hokupaa adaptive optics beware PSF & background (Melatos et al. 04) Crab: wisps I & II J K Vela: X-ray jet = fire hose
Crab: sprite + rod + 20 min (Pavlov et al. 03) +2d RADIO ELECTRONS Radio, X-ray wisps coincide Move in concert ( 0.24c) Uniform radio spectrum VLA,5 GHz
radio and X-ray e accelerated together! Near-IR spectrum varies: sprite -0.2 wisps -0.70.1 (Bietenholz et al. 01) MULTI- DIAGNOSTICS Wisp structure wind composition Ion cyclotron acceleration and-rays Confinement geometry energy transport Energy flux versus latitude Electromagnetic or kinetic? Polarization magnetic field geometry
Collimation and stability I. WISPS = ION SHOCK? Ions gyrate B field compressed ion bunches variability (Spitkovsky & Arons 02; cf. Komissarov & Lyubarsky 03) Internal structure of shock resolved unique!
Ion current = Goldreich-Julian (dNi/dt 1034 s-1) Neutrinos! p p (in known ratio L : L) II. CONFINEMENT GEOMETRY X-ray backflow from aft shock bow shock + CD radio backflow from fore shock termination shock Example: The Mouse (Gaensler et al. 03) Radio + X-ray synchrotron tails
Mach number from stand-off distance ENERGY FLUX VS LATITUDE Shape: ram pressure Brightness: Doppler Anisotropic wind or ISM density gradient (Chatterjee & Cordes 04) Monopole flux sin2(Komissarov & Lyubarsky 03) (Gaensler et al. 02)
EM KE CONVERSION = EM flux : KE flux Shock: 10-3 so MHD flow can decelerate from shock (c/3) to edge of PWN (1500 km s-1) Pulsar: 106 (e cascades) Force-free linear accelerator (Contopoulos et al. 02) Reconnection in striped wind (Lyubarsky & Kirk 01) Wave conversion via instability (Melatos 98) Striped wind: Vphase = Vwind Reconnection and heating (Lyubarksy & Kirk 01)
Electromagnetic wave: large amplitude (p) Unstable (Melatos & Melrose 96) Puzzles How launched? Synchro-Compton radn? Energy transport? neutral sheet E E B
B V V alternating B III. POLARIZATION = B FIELD 3C58 in X-rays (Murray et al. 02) MHD simulations
(van der Swaluw 03) Collimation: postshock hoop stress (E+JB 0 before the shock) & anisotropic energy flux Disruption of B MHD kink instability (Begelman 98) BUT poln regular regenerated by dynamo? SUMMARY Radio-to-X-ray PWN: SN remnant, ISM, eclipsing binary Shock = crossbow which varies daily PSR wind = two-zone large-amplitude wave
Radio & X-ray wisps ions ISM bow shock anisotropic energy flux SNR calorimeter EM : KE Radio & X-ray poln B field & collimation
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