Comptonized X-rays from Relativistic Jets in Active Galactic Nuclei

Milton Arencibia (P&A, UCL; U. de La Laguna)Supervisor: Prof. Kinwah Wu (MSSL, UCL)

Contents

• Basic AGN jet physics & astrophysics

• Structured jets and spectral formation

• MC simulation & numerical model

• Results

Jets in Active Galactic Nuclei (AGN)

Basic AGN Jet Physics & Astrophysics

Imaging observations of structured jets

Credit: NASA; NRAO, STScIBasic AGN Jet Physics & Astrophysics

Spectral observation of structured jets

M87 Jet

Basic AGN Jet Physics & Astrophysics

Credit: Böhringer et al. (2001) &Berghöfer et al.

Spectral observation of structured jets

More M87

Basic AGN Jet Physics & Astrophysics

Credit: J.A. Biretta, C.P. Stern, D.E. Harris

Diversity & complexity of structured AGN jets

• Knots – shocks

• Quenched jets– Entrenching in IGM

• Bent jets• Bubble blowing jets

Structured Jets & Spectral Formation

Credit: J.A. Biretta, F.N. Owen

Diversity & complexity of structured AGN jets

• Knots– shocks

• Quenched jets– Entrenching in IGM

• Bent jets• Bubble blowing jets

Structured Jets & Spectral Formation

Credit: C. Saxton, K. Wu

Diversity & complexity of structured AGN jets

• Knots– shocks

• Quenched jets– Entrenching in IGM

• Bent jets• Bubble blowing jets

Structured Jets & Spectral Formation

Diversity & complexity of structured AGN jets

• Knots– shocks

• Quenched jets– Entrenching in IGM

• Bent jets• Bubble blowing jets

Structured Jets & Spectral Formation

Radiative processes in relativistic jet plasmas

• Synchrotron radiation

• Compton scattering

Basic AGN Jet Physics & Astrophysics

Credit: P.A. Hughes

Radiative processes in relativistic jet plasmas

• Synchrotron radiation

• Compton scattering

Basic AGN Jet Physics & Astrophysics

Credit: L. Van Speybroeck

Frequency shift in Compton scattering

Relativistic Compton scattering in OF:

Competition between relativisticboosting and scattering recoil

Basic AGN Jet Physics & Astrophysics

Spectral formation with Compton scattering

• Kompaneets equation

Doppler boostingSources (injection)

SinksInduced scattering

Compton recoil

Basic AGN Jet Physics & Astrophysics

Monte Carlo simulation

Monte Carlo Simulation & Numerical Model

q(x)

Compton scattering

Yes

No

Bin to spectrum

still in jet?

No

Yes

Simulation scheme

Monte Carlo Simulation & Numerical ModelMonte Carlo Simulation & Numerical Model

Jet opening angle ~1/Γ

Fixed viewing angle i=7.5ºOptical depth ~ 3E-3Injection spectra:

•Jet synchrotron•Thermal disk•CMB

Simulation scheme

Monte Carlo Simulation & Numerical ModelMonte Carlo Simulation & Numerical Model

Jet opening angle ~1/Γ

Fixed viewing angle i=7.5ºOptical depth ~ 3E-3Injection spectra:

•Jet synchrotron•Thermal disk•CMB

Simulation scheme

Monte Carlo Simulation & Numerical ModelMonte Carlo Simulation & Numerical Model

Jet opening angle ~1/Γ

Fixed viewing angle i=7.5ºOptical depth ~ 3E-3Injection spectra:

•Jet synchrotron•Thermal disk•CMB

Power law density, low speed jet (Γ=5)

Results

CMB Disc Synchrotron

α~1.64 α~1.3 α~ 1.63

Power law density, medium speed jet (Γ=40)

Results

CMB Disc Synchrotron

α~1.64 α~ 1.65

Periodic density, low speed jet (Γ=5)

Results

CMB Disc Synchrotron

α~1.63 α~1.68

Periodic density, medium speed jet (Γ=40)

Results

CMB Disc Synchrotron

α~1.63 α~1.68

Exponential density, low speed (Γ=5)

Results

CMB Disc Synchrotron

α~1.63 α~1.71

Exponential density, medium speed (Γ=40)

Results

CMB Disc Synchrotron

α~1.65 α~1.68

Interpretation?

Results

Greater boosting along smaller escape angles

No steepening/flattening of spectra for differently structured jets

Further study?

A more realistic jet model would include radial dependence (jet spine with τ~1) and NLR+BLR injection

Questions?

• P.A. Hughes, “Beams and jets in astrophysics”, 1991, Cambridge Astrophysics Series 49, Cambridge University Press