real vs. simulated relativistic jets

Real vs. Simulated Real vs. Simulated Relativistic JetsRelativistic Jets

Socorro 2003

Instituto de Astrofísica de Andalucía (CSIC), Granada, SpainInstitut d’Estudis Espacials de Catalunya/CSIC, Barcelona, Spain

José L. Gómez

OverviewOverview

Development of Relativistic Numerical Development of Relativistic Numerical CodesCodes

What have we learned?What have we learned?• Observations of the inner jetObservations of the inner jet• Interpretation using the simulationsInterpretation using the simulations

What the future may bringWhat the future may bring

Computation of the non-thermal emission from the HD results, allowing synthetic maps directly comparable with observations

Gómez et al. (1995-7); Mioduszewski et al. (1997); Gómez et al. (1995-7); Mioduszewski et al. (1997); Komissarov & Falle (1997); Agudo et al. (2001)Komissarov & Falle (1997); Agudo et al. (2001)

1995: 1995: 2D RHD+E2D RHD+E

Gómez et al. (1997)Gómez et al. (1997)

Martí et al.Martí et al.

Relativistic Numerical CodesRelativistic Numerical Codes

First Relativistic HD codes capable of solving the conservation equations for rest-mass and energy-momentum

van Putten (1993); Martí et al. (1994-5-7); Duncan van Putten (1993); Martí et al. (1994-5-7); Duncan & Hughes (1994); Falle & Komissarov (1996)& Hughes (1994); Falle & Komissarov (1996)

1993-4: 1993-4: 2D RHD2D RHD

1996: 1996: 2D RMHD2D RMHD

First studies of the magnetic field influence in the flow of relativistic jets

van Putten (1996); Koide et al. (1996); Komissarov (1999)van Putten (1996); Koide et al. (1996); Komissarov (1999)

Relativistic Numerical CodesRelativistic Numerical Codes

Extension to 3D RMHD by Nishikawa et al. Nishikawa et al. (1997-8)(1997-8)

1997: 1997: 3D RMHD3D RMHD

1998: 1998: GRMHDGRMHD

First Simulations for General Relativistic MHD mainly aimed to study jet formation

Koide et al. (1998,1999,2002); Meier et al. (2001); Koide et al. (1998,1999,2002); Meier et al. (2001); Gammie et al. (2003); de Villiers & Hawley (2003)Gammie et al. (2003); de Villiers & Hawley (2003)

Koide et al. (1999)Koide et al. (1999)

First computation of synthetic images, including all relativistic effects (time delays), from high resolution 3D RHD simulations by Aloy et al. (2003)Aloy et al. (2003)

2003:2003: 3D hr-RHD+E 3D hr-RHD+E

1999:1999: 3D hr-RHD 3D hr-RHD

3D high resolution RHD simulations

Aloy et al. (1999, 2000); Hardee (2000); Hughes et Aloy et al. (1999, 2000); Hardee (2000); Hughes et al. (2002)al. (2002)

Aloy et al. (1999)Aloy et al. (1999)

The VLBA has allowed to monitor multiple sources with unprecedented time and spatial resolutions.

Some of the programs (not a complete list): 3-year of bi-monthly polarimetric 43 GHz

observations of 15 sources including 3C279, 3C273, BL Lac, OJ287, etc. Big collaboration by Marscher, Jorstad, et al.Big collaboration by Marscher, Jorstad, et al.

Further information (images & movies) in:Further information (images & movies) in:http://www.bu.edu/blazars/research.htmlhttp://www.bu.edu/blazars/research.html

See also poster by Jorstad et al.See also poster by Jorstad et al.

What have we learned? Inner Jet StructureWhat have we learned? Inner Jet Structure

BL Lac by Stirling et al. (2003)BL Lac by Stirling et al. (2003)

Evidence for jet in precession

Inner (outer) ballistic (non-ballistic) motions

Structural position angle vs. time

Further BL Lac studies by:

Denn et al. (2000)Denn et al. (2000)Gabuzda & Cawthorne (2003)Gabuzda & Cawthorne (2003)

Wehrle et al. (2001)Wehrle et al. (2001)

3C279 at 22 GHz3C279 at 22 GHz 22 and 43 GHz VLBA observations of 3C279


A kinematical analysis shows indications of inward motions for a component associated with a jet recollimation shock.


Some of the programs (not a complete list):

Motions in a sample of 42 -ray bright blazars


Jorstad et al. (2001)Jorstad et al. (2001)

Most of the sources present stationary features:

Close to the core associated with recollimation shocks Farther down the jet associated with bends



22 and 43 GHz polarimetric long-term (20+12 epochs) monitoring of 3C120 by Gómez et al.Gómez et al.


Gómez et al. (2000, 2001)Gómez et al. (2000, 2001)




Gómez et al. (2000, 2001)Gómez et al. (2000, 2001)

The “head” of the component (o1&02) moves at a constant velocity of 4.4 c

Subluminal trailing componentstrailing components appear in the wake of the main feature

22 and 43 GHz polarimetric long-term (20+12 epochs) monitoring of 3C120 by Gómez et al.Gómez et al.



What have we learned? (Real vs. Sim.)What have we learned? (Real vs. Sim.)Observations show:Observations show:

Jet precession is increasingly common

Mixture of ballistic motions and components moving in curved paths

Coexistence of stationary and moving features, presenting complex variability

Indications of inwards motions and trailing components

Very complex polarization structures, suggestive of shocks, but also of toroidal and oblique fields

Jet/external medium and clouds interactions

Simulations say:

What have we learned? 2D Sim. of Jet PerturbationsWhat have we learned? 2D Sim. of Jet Perturbations

First 2D+ RHD+E simulationsFirst 2D+ RHD+E simulations

Aimed to study the relationship between superluminal components and shocks (Marscher & Gear 1985(Marscher & Gear 1985))

Mioduszewski et al. (1997):Lorentz factor modulation between 1 and 10 at the jet inlet leading to a series of knots.

Mioduszewski et al. (1997)Mioduszewski et al. (1997)

Emissivity

Doppler Boosting at 30o

Emission is determined by a complex combination of emissivity and Doppler boosting

60o

90o

Darker gray means higher value

Komissarov & Falle (1997):Generation of standing and moving features.

Time-delay effects allow to study superluminal motions.

Time

Synthetic maps including all relativistic effects (time-delays)Synthetic maps including all relativistic effects (time-delays)

Stationary model

First 2D+ RHD+E simulationsFirst 2D+ RHD+E simulations

Aimed to study the relationship between superluminal components and shocks (Marscher & Gear 1985(Marscher & Gear 1985))

What have we learned? 2D Sim. of Jet PerturbationsWhat have we learned? 2D Sim. of Jet Perturbations

Gómez et al. (1997):Simulation of an over-pressured jet, with =4, in which a short increase in from 4 to 10 is included.

Gómez et al. (1997)Gómez et al. (1997)

Recollimation shocks Stationary comps.

Perturbation Superl. comp.

Interaction between both leads to: Temporal dragging of the “stationary” Inward phase motionInward phase motion of the “stationary”, as

claimed by Wehrle et al. (2001)Wehrle et al. (2001) for 3C279

A good temporal sampling is needed for a correct components’ identification

Measured apparent velocities may depend on observing frequency (resolution)

Simulation: Light =4 jet in pressure equilibriumpressure equilibrium with the external medium

Shock: Generated by introducing a short living perturbation in the injection Lorentz factor (=4 to 10) and an increase in pressure by a factor of 2

Interaction of the shocked material with the external medium and the underlying jet leads to the formation of “trainling Shocks”.“trainling Shocks”.

Agudo et al. (2001)Agudo et al. (2001)

What have we learned? 2D Sim. of Jet Perturbations


Computation of the emission by solving the transfer equations for synchrotron radiation at the retardedretarded times

Main shock produces a superluminal component

Agudo et al. (2001)Agudo et al. (2001)

Multiple trailing components appear in the wake of the main feature

Space-Time diagram for the components in 3C120

Main ComponentMain Component

TrailingsTrailings

The inner structure in the jet of 3C120 can be interpreted as produced by “trailing components” (Gómez et al. 2001Gómez et al. 2001). Further evidence for trailing components in Centaurus A (Tingay et al. 2001Tingay et al. 2001) and other sources (Jorstad et al. 2001Jorstad et al. 2001)

A single perturbation can produce multiple components

The emission structure variability can be interpreted with a smaller activity of the central engine (black hole + disk)



What have we learned? 3D SimulationsWhat have we learned? 3D Simulations

3D RHD: Jet response to precession3D RHD: Jet response to precession

First 3D RHD simulations are dedicated to study the propagation and stability of jets in precession. Aloy et al. (1999,2000); Hardee et Aloy et al. (1999,2000); Hardee et al. (2001); Hughes et al. (2002)al. (2001); Hughes et al. (2002)

Hardee et al. (2001)

Interaction of the helical surface and body wave modes leads to enhancement in the line-of-sight images.

Line-of-sight integration of p2 for a =2.5 precessing jet

Hardee et al. (2001)Hardee et al. (2001)

The modes are triggered with a fixed phase difference at the inlet, and present different mode wavelengths:

Wave-wave interactions Stationary comps.

Individual wave patterns Moving. comps.

Complex changingchanging structure of coexisting stationary and moving components

Hughes et al. (2002)Hughes et al. (2002)

=5 Jet

p

p & v

HST D GE I A B C

(Perlman et al. 2001)

What have we learned? 3D SimulationsWhat have we learned? 3D Simulations

Lobanov, Hardee & Eilek (2003)Lobanov, Hardee & Eilek (2003)

HST Image

Simulated intensity image

M87 intensity distribution is interpreted as resulting from the interaction of helical and elliptical modes.

See also poster by Lobanov, Hardee & EilekSee also poster by Lobanov, Hardee & Eilek

What have we learned? 3D Sim. of Jet PerturbationsWhat have we learned? 3D Sim. of Jet PerturbationsSimulation: 3D hr-RHD+E3D hr-RHD+E of a precessing with with traveling perturbation of a precessing with with traveling perturbation

Light (=10-3), relativistic (=6), precession pitch angle of ~2o

Shock: Perturbation with a 4 times increase in density and energy during 0.8Rb/c

Blue for the jet surface White for the Lorentz factorWhite for the Lorentz factorColor gradient for pressure

Aloy et Aloy et al. al.

(2003)(2003)

Precession leads to jet/external medium interactions

Component initially moves ballisticaly, leading to interactions with the external medium that increase its internal pressure

The perturbation evolves splitting into two (A,B) different regions

Pink shows

Green shows

Observer’s reference frame

Time

Time delays stretches the structure as seen in the observer’s frame

3 Rb

10 Rb



Associated peak brightnesspeak brightness motion reflects changes in the internal distribution

New stretchedstretched region with increased emission

Upstream motionsUpstream motions during moving/standing components interaction

Standing components associated with the recollimation shocks






We only “see” the back portion of the perturbation

Viewing angle selection effect






We only “see” the back portion of the perturbation. Viewing angle selection effectViewing angle selection effect

Slow moving “helical” components

Space-Time diagram

Helical component






We only “see” the back portion of the perturbation. Viewing angle selection effectViewing angle selection effect

Its ballistic motion leads to a differential brightness distribution across the jet width

Slow moving “helical” components

Aloy et al. Aloy et al. (2003)(2003)



What have we learned? (Real vs. Sim.)What have we learned? (Real vs. Sim.)Observations show:Observations show:

Jet precession is increasingly common

Mixture of ballistic motions and components moving in curved paths

Coexistence of stationary and moving features, presenting complex variability

Indications of inwards motions and trailing components

Very complex polarization structures, suggestive of shocks, but also of toroidal and oblique fields

Jet/external medium and clouds interactions

Simulations say:

Over-pressured jets may lead to recollimation shocks, i.e., standing features

Superluminal components may be obtained from different perturbations at the jet inlet (, p, )

Complex interactions between moving and standing shocks leading to inward motions and frequency dependent apparent velocities

Equally complex for wave-wave interactions

Trailing shocks may be expected

Time delays stretches internal shocked structure, which appearance depends on the viewing angle (selection effect)

General good agreement between Observations and Simulations, proving one of the most powerful tool for the study of relativistic jets

Expect very complex internal jet structure variability. Shock-in-jet models (1-component-Expect very complex internal jet structure variability. Shock-in-jet models (1-component-1-shock) may be an over-simplistic idealization1-shock) may be an over-simplistic idealization

Perhaps it is time to forget about Gaussian model fits and start paying attention to the Perhaps it is time to forget about Gaussian model fits and start paying attention to the image pixel. Good time samplings are requiredimage pixel. Good time samplings are required

What the future may bringWhat the future may bring

Open questions:Open questions:

Mechanisms of jet formation, collimation, and acceleration

What is the role played by the magnetic field?

What is the jet composition?

Better understanding of the superluminal and stationary features

Jet/external medium and clouds interactions. Is it important at pc-scales?

Emission at “high” energies (optical, x-rays, -rays)

Particle acceleration and electron aging along the jet and radio lobes

Numerical simulations:

RMHD models allow to study:Acceleration and collimationPolarization in componentsJet Stratification

GRMHD models:Jet formation

New EOSJet composition

RHD + Emission ModelsRHD + Emission Models

Electron energy transportRadiative losses (e- aging) and particle

acceleration

Inverse Compton (SSC, EC)High energy emission

3D GRMHD + Emission models + Microphysics (EOS, e-, part. acc., ...)

real vs. simulated relativistic jets

Documents

multiple sources

inner jet structuregmez

inner jet interpretation

inner jet structurejorstad

unprecedented time

jet precession

jet perturbationsfirst

jet inlet