1 / 12

Helically Twisted Shocks in the M87 Jet

Helically Twisted Shocks in the M87 Jet. Philip Hardee 1 , Andrei Lobanov 2 & Jean Eilek 3 1 The University of Alabama, Tuscaloosa, AL, USA 2 Max-Planck Institut f ü r Radioastronomie, Bonn, Germany 3 New Mexico Tech/NRAO, Socorro, NM, USA. RadioGals08, Cambridge, MA. Introduction.

kali
Download Presentation

Helically Twisted Shocks in the M87 Jet

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Helically Twisted Shocks in the M87 Jet Philip Hardee1, Andrei Lobanov2 & Jean Eilek3 1The University of Alabama, Tuscaloosa, AL, USA 2 Max-Planck Institut für Radioastronomie, Bonn, Germany 3 New Mexico Tech/NRAO, Socorro, NM, USA RadioGals08, Cambridge, MA

  2. Introduction Questions potentially answered by studying jet structure Marshall et al. (x-ray) • Structure: What is the cause? • Outflow: What are the jet plasma conditions? • Dynamics: Are proper motions flow or pattern? • Microphysics: Where are particles accelerated? Perlman et al. (optical) Basic facts: D ~ 16 Mpc, 1” ~ 77 pc Nuclear region: Mbh ~ 3 x 109 Msol ; initial collimation < 100RG (Junor, Biretta & Livio 1999) radio: twisted structure & limb-brightened (Owen, Hardee & Cornwell 1989) optical: brighter knots & spine than radio (Sparks, Biretta & Macchetto 1996) X-ray: knots, interknot emission & spectrum steepens along jet (Perlman & Wilson 2005) Zhou et al. (radio)

  3. Similar Optical & Radio Structure HST R band: (Perlman et al. 2001) VLA 15GHz: (Biretta, Zhou & Owen 1995) H D E F I I F A E A D H Biretta, Sparks & Macchetto et al. (1999) Filament Crossing (?) & Twist (?) F Twisted Filament (?) & Filaments (?) D E

  4. Image Analysis & Structure Single gaussian (SG): ridge line Double gaussian (DG): internal 550 slices Dual twisted filament structure recovered by double Gaussian in VLA and HST images. lSG 13.8”constant (HST-1 to Knot A) lDG 2”(HST-1 @ 1”) - 3”(Knot A @ 12”) VLA HST

  5. Observed Proper Motions/Viewing Angle • Typical Radio “Knot” Motions • <ob> (HST-1) < 0.25c (Cheung, Harris & Stawarz 2007) • <ob> (D)  0.40c (Biretta, Zhou & Owen 1995) • <ob> (F)  0.90c (Biretta, Zhou & Owen 1995) • Fast Optical Motions (Biretta, Sparks & Macchetto 1999) • ob 6c through HST-1 Viewing angle j < 19o • ob 5c through Knot D • ob 4c through Knot E • Fast Radio Motions (Cheung et al. 2007; Biretta et al. 1995) • ob >  3c through HST-1  Viewing angle j < 35o • ob 2.5c through Knot D • Implications • Superluminal speeds decrease  bulk speed • Subluminal speeds increase pattern speed (Biretta, Sparks & Macchetto 1999) superluminal optical subluminal optical

  6. Accelerating Pattern/Viewing Angle Pattern Acceleration (HST-1 to Knot A) lDG  2’  3”Eob increase 50% lSG 13.8”Hob  constant Jet Speed @ HST-1 & Viewing Angle (A)6c 7.5 (optical) @  = 150 viewing angle (B)3c 4 (radio) @  = 300 viewing angle Pattern Speed (radio motions) : (1) Knot D-- Eob  0.4c– (slow pattern) (2)Knot F --Eob  0.9c– (fast pattern) Case A: fast jet Case B: slow jet F D Observed change < Intrinsic change

  7. Decelerating Jet/Accelerating Sheath • Jet Deceleration/Sheath Acceleration: • KH interface driven moving shocks • Jet energy flux transferred to sheath • Some Basic Assumptions: • Treat Jet like radial wind • Jet & sheath pressure balance • Sheath thickness  1.5 Rj (set by E mode) Decelerating Expansion (HST-1 to Knot D)  radius expansion factor 3.5 (Case A)6c 7.5 to 5c 5 (optical) @  = 150 viewing angle (Case B)3c 4 to 2.5c 3.5 (radio) @  = 300 viewing angle Helically Twisted Dual Filament Jet Shock: Kelvin-Helmholtz Elliptical Mode sheath jet Helically Twisted Sheath Shock

  8. KH Twisted Filaments Intensity Image & Magnetic Pressure Cross Sections (Hardee et al. 1997) 30 36 42 Dual Helically Twisted filaments Theoretical Pressure structure of Elliptical surface mode Theoretical Pressure structure of 1st Elliptical body mode

  9. Decelerating Jet/Accelerating Sheath Case B: slow jet @  = 300 viewing angle Conserve Jet Energy/Mass Flux (to Knot A)  obtain jet deceleration (Case A)6c 7.5 to 3c 3(fast jet) (Case B)3c 4 to 2c 2(slow jet) (1)Slow Pattern (2) Fast Pattern P0 : 10-9 dyne cm-2 L0 : ~ 1043 erg s-1 Msol : ~ 10-5 yr-1 Lose Fraction Jet Energy Flux  calculate sheath density & speed 1. E mode wavelength/speed increase & near resonance 2. Sheath energy flux = lost jet energy flux

  10. Growth, Saturation & Structure Spatial Growth Rates Intrinsic Pressure & Velocity Structure (multiple modes shown) transonic supersonic Pressure and velocity changes 1D cuts along jet at fixed r/Rj Approximate Apparent Dual Filament Pressure Structure HST-1 Knot A

  11. Morphology HST-1 to Knot A B  nj2/3; = 0.7 FastJet & Slow Pattern @ 15o viewing angle D E F I Slow Jet &Fast Pattern @ 30o viewing angle HST @ R band: (Perlman et al. 2001) VLA @ 15GHz: (Biretta, Zhou & Owen 1995) E F D

  12. Summary/Conclusions • Dual twisted filament pair from HST-1 to Knot A. • Radio/optical filament structure correlated (optical more compact). • Oscillation described by SG = 13.8” (long wavelength Hs mode). • Dual twisted filament pair DG = 2 - 3” (resonant frequency Es mode). • Knots are not filament crossing projection. (other shock/adiabatic compression) • Energy/Mass Flux conserving models (~ 1043 erg s-1 , ~ 10-5Msolyr-1) : • 1) Decelerate jet/accelerate sheath, increase sound speed (Es mode resonant) 2) Pattern speed  twisted shocks weaken & filling factor reduced • 10s (HST-1) > shockMshock > few (knot I) @ jet surface • particle injection energy spectrum steepens • 3) Jet transonic at Knot A  rapid destabilization • 4) Morphology  lower Lorentz factor, larger viewing angle, faster pattern. • (fastest optical proper motions phase effects?) 1 pc 0.03 pc

More Related