Turbulence Acceleration Model for the Broad Band Blazar Spectra - PowerPoint Presentation

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Uploaded On 2020-08-04

Turbulence Acceleration Model for the Broad Band Blazar Spectra - PPT Presentation

Katsuaki Asano ICRR U Tokyo Collaborators Yuto Teraki YITP Kyoto Masaaki Hayashida ICRR Fumio Takahara Osaka etc Nonthermal Emission Supernova Remnant SN1006 ID: 797439

acceleration amp hard energy amp acceleration energy hard model spectrum injection electron diffusion parameters hayashida emission steady blazar asano

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Slide1

Turbulence Acceleration Model for the Broad Band Blazar Spectra

Katsuaki

Asano

（

ICRR, U. Tokyo

）

Collaborators:

Yuto

Teraki

(YITP, Kyoto), Masaaki

Hayashida

(ICRR),

Fumio

Takahara

(Osaka) etc.

Slide2

Non-thermal Emission

Supernova Remnant SN1006

Consistent with the diffusive shock acceleration (Fermi I)+Bohm Limit!

All non-thermal phenomena are due to shocks?

Acero

+ 2010

Electron energy distribution:

Single power-law with the index of 2.1,

cut off at 10 TeV and B=30μG.

Bohm Limit (

) &

Slide3

Open Problems in Blazar Emission

Kino,

Takahara

Kusunose

2002

Index harder than

2 for the electron injection spectrum.2. Lower maximum energyMrk 421：B=38mGIf even for .But actual Max. Energy

3. Too sharp break in the electronspectrum.Compared to the cooling break,the difference in the indicesseems large.Inoue & Takahara 2002

The Bohm factor should be

Slide4

Electron Index in Fermi BL Lacs

Yan+

Slide5

Many Parameters in Broken-power-law fit

Need

double break

and

low-energy cut-off

Radio should be different component in this case

Slide6

Particle Acceleration in Blazar Jets

Shock Acceleration may be hard in highly magnetized plasma.

Kirk &

Heavens 1989, Lemoine

& Pelletier 2010, Sironi+ 2013 etc.In blazar

Sironi+ 2015

The parameter range is very limited.Acceleration via turbulence

Park & Petrosian 1995

Becker & Dermer 2006Stawarz & Petrosian 2008

Bottcher+ 1999Schlickeiser & Dermer 2000Lefa+ 2011Kakuwa+ 2015In BlazarsIn GRBsBykov & Meszaros 1996Dermer & Humi 2001Asano & Terasawa 2009, 2015Murase+ 2012

Slide7

Phenomenological Treatment

Kolmogorov+Alfvenic

q=5/3, Compressible q=2 (hard sphere)

Diffusion

Acceleration

Cooling

Injection

No cooling, continuous injection, time evolution

harder than the shock case

Stochastic Acceleration due to turbulence

order Fermi acc.) leads to a hard spectrum.

Slide8

Interaction with Alfven Wave

Energy gain per scattering

Alfvenic

Wave (transverse/incompressible)

pitch angle diffusion

→

mean free path

resonance condition

However, the ratio

is typically 0.1 in blazars.

It seems that the Alfven waves cannot be the

enrgy

source.

Slide9

Steady outflow

Continuous shell ejection with a width of R

/Γ in commoving frame

Elecrton injection from R=R

to 2R

with stochastic accelerationTurbulence Index: Kolmogorov q=5/3Both injection and acceleration stop at R=2R0Our ModelElectron injectionStochastic accelerationSynchrotron emission and coolingInverse Compton emission and coolingAdiabatic cooling （V∝R2）Photon escapeNo electron escape!

Physical Processes

Slide10

Simple case

Constant injection & constant diffusion coefficient

Electron spectrum

Energy density ratio

Slide11

１ES 1101-232

The simple model can reproduce the spectrum of 1ES 1101-232

Slide12

But, in Mrk 421…

Slide13

But, in Mrk 421…

To produce a soft spectrum, increasing injection rate

with radius is assumed.

Hard to reconcile GeV

data.

Magnetic Energy is subdominant.

Alfven Wave is actually responsible?

Slide14

Alternative: Compressible Waves

Fast

Slow

x5 speed

Slide15

Acceleration by compressible wave

Transit Time Damping (Scatter by mirror force)

Formulae of Energy Diffusion Coefficient:

Ptuskin

1988

Cho &

Lazarian

2006

Lynn+ 2014

Non-resonant (need spatial diffusion

coeff

Resonant (

)

The largest scale eddy dominates

The amplitude

is dominated by the

smallest scale for q<2.

is written with the smallest eddy?

Slide16

Projection

Test particle

simulation in pure linear

Fast Waves

Fast

, 10 mode

Kolmogorov

High-beta plasma

Teraki

& Asano in prep.

Slide17

Results of the Test Particle Simulation

Inject

(weak

turb

While only a small fraction of particles of

can be accelerated for

almost all of relativistic particles are accelerated in

Preliminary

Mirror force:

Interaction Time scale:

Electric Field:

Energy Gain Rate:

Hard Sphere

Slide18

Hard-Sphere Model

Parameters are

Required for any model

Only

one

peculiar parameters

Cho &

Vishniac

2000

Supposing the compressional waves

are responsible, we model as following.

Parameters are constant during the dynamical

time scale

, and injection and acceleration

suddenly shutdown after that.

Slide19

Mrk421

Low maximum energy and curved electron spectrum are naturally reproduced

with temporal evolution effects.

Turbulence Acceleration Model for the Broad Band Blazar Spectra - PowerPoint Presentation

Turbulence Acceleration Model for the Broad Band Blazar Spectra - PPT Presentation

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