Are blazar jets matter or
poynting-flux dominated?
+ short introduction of this Session“Particle Acceleration Mechanisms in Astrophysical Sources“

M.Hayashida et al. 2015, ApJ, in press(arXiv:1502.04699)
CTA-Japan workshop
at ICRR on 14 January 2016

Masaaki Hayashida(Institute for Cosmic-Ray Research, the University of Tokyo)

1	  Outline
1. A Short introduction of this session“Particle Acceleration Mechanisms in AstrophysicalSources”!

2. Acceleration mechanism in blazar jets#–Observational results (Fermi-LAT) from blazar 3C279#
Two huge outbursts#a. Flare on 20th December 2013 (Hayashida+15, ApJ)#– hard γ-ray index#– high Compton dominance: LIC/Lsyn ~ 1000 #b. Flare on 16th June 2015 (Fermi-LAT Coll. 16)#
– Very fast variability#

Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#2	  Particle accelerations inastronomical sources
Hillas diagram!
maximum energy: Emax#
Larmor radius(rL = Emax/ZeB)#
is smaller thansource size, R#

rL = R à#Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#3	  1st-order Fermi acceleration
Diffusive Shock Acceleration (DSA) #by Scholer#

V1 / V2 + 2
dN/dE ∝ E-p : p =# V / V −1 > 2
1
2
Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#

V1/V2=4 at M>>1#(M: mach number)#4	  Supernova remnant as Cosmic-ray origins!
(Fermi-LAT Coll. 2013, Science)#

W44!

Jan. 14, 2016 CTA-Japan workshop#

IC443!

Masaaki Hayashida (ICRR, U. Tokyo)#5	  Diffusive shock acceleration (DSA) in SNR!

SN 1006(Credit:X-ray: NASA/CXC/
Rutgers/G.Cassam-Chenai,
J.Hughes et al.; Radio: NRAO/
AUI/NSF/GBT/VLA/Dyer,
Maddalena & Cornwell;
Optical: Middlebury College/
F.Winkler, NOAO/AURA/NSF/
CTIO Schmidt & DSS)

6	  (more in Amano-san’s talk)#

Crab flare: reconnection?

• Compactness: tvar~4-8 hrs à Emission region 3x10-4 pc#• Hard spectrum: Γ~1.3, inconsistent with shock acceleration#• Synchrotron 375 MeV > 160 MeV (radiation reaction limit)#à challenge classical acceleration models#

1. Doppler beaming? (but not seen in the Crab) #2. Reconnection!? à Zenitani-san’s talk!
Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#7	  extra-galactic: relativistic jet
AGN jet:!
• the most dominantgamma-ray source#• origin of Ultra-highenergy (~1020 eV)
cosmic rays?#(Kotera&Olinto 2012)#

Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#8	  Blazar Jets
• where is the gamma-ray emission site?
(~ where is the jet dissipation region?)#• what is the acceleration mechanism?
(DSA (Fermi-I), Stochastic (Fermi-II), reconnection?)#• what is the dominant component in the jets?
(matter or Poynting flux dominatedat the gamma-ray emission region?)!

!

 relativistic Jet formation!
Jan. 14, 2016 CTA-Japan workshop#Masaaki Hayashida (ICRR, U. Tokyo)#9	  Relativistic Jet Formation(these days) commonly considered: MHD mechanism!
Blandford-Znajek process:#
3DMHD simulation (BZ effect)#(from rotating BHs)#(Blandford&Znajek ‘77)!

(McKinney&Blandford 09)#(c.f, Blandford&Payne 82,
from magnetized accretion disk)#

are the jets strongly magnetized?!
Jan. 14, 2016 CTA-Japan workshop#Masaaki Hayashida (ICRR, U. Tokyo)#talks by!
Kojima-san!
Mizuta-san!
10	  Gamma-ray emission from AGNs
AGNs with relativistic jet!
Inverse-Compton scattering
by electrons in the jets #e+/e-­‐	  νFν	seed photon:#synchrotron: SSC#
external: EIC #ν	  1GeV!

RadioBlazar ! Galaxies !
• low power BL Lac

FR I#• high power FSRQFR II#

small viewing angle#
mis-aligned-> relativistic beaming# blazar ?#Jan. 14, 2016 CTA-Japan workshop# Masaaki Hayashida (ICRR, U. Tokyo)#11	  Emission from Jets (FSRQ)
3C 279 (Hayashida+12, ApJ, 754, 114) #synchrotron!

Jan. 14, 2016 CTA-Japan workshop#(external)
inverseCompton!

12	  “where is the gamma-ray emission site?”	
(HESS 07)#Dusty	  torus	
accre6on	  disk	

Broad	  emission	  	  line	  region	  (BEL)	

e+	

BH	e-­‐	γ	γ	e+	e-­‐	

UV	  photon	magnetic
dominated?!

particle dominated?!

0.01-­‐0.1pc	  (~103	  Rg	  )	Jan. 14, 2016 CTA-Japan workshop#(fast variabilityin BL Lacs)!

IR	  photon	a	  few	  pc	  (~105	  Rg	  )	Near side?
15-17 cm)(10γ	orγ	 Far side?
(1018-20 cm)(TeV detectionfrom FSRQs)!
to avoid#
γVHE + γUV-­‐>e+ e-	  #Masaaki Hayashida (ICRR, U. Tokyo)#13

3C 279 γ-ray activity for 7 years
7 year light curve (2008 Aug. – 2015 Aug.)
250
200

2015 June

preliminary

Fermi-LAT: > 100 MeV(1 day bin)2013 Nov – 2014 Apr(Hayashida+15, ApJ)

150
100
5000500

1000

1500

2000

[MJD - 55000]

1! 2!

3!

Three large outbursts with flux (>100 MeV) (1 day average)!
1. 2013 December 20 : 6.0 x 10-6 ph cm-2 s-1!
2. 2014 April 03!
!: 6.4 x 10-6 ph cm-2 s-1!
3. 2015 June 16 !
: 24.3 x 10-6 ph cm-2 s-1!
Masaaki Hayashida (ICRR, U. Tokyo)

Jan. 14, 2016 CTA-Japan workshop

14

Flare profile(MH+15, ApJ)#

1!

2!

rise# fall#
1!
2!

• asymmetric profile#• hourly scale variability at 100 MeV: #•very efficient cooling à need dense external photon à inside BLR!

Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#15	  LAT Spectrum(MH+15, ApJ)#Red (Flare 1, Period B)!
• Very hard index(1.71±0.10)
typ. FSRQ: ~2.4#• peaked at a few GeV
typ. FSRQ: < 100 MeV#

Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#16	  Multi-band light curve
Period (B):#no flare in other bands“orphan” γ-ray flare!

Kanata,SMART#
Kanata#SMA#(MH+15, ApJ)#
Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#17	  Broad band SED(3 days)#(0.2 days)#(3 days)#(0.27 days)#

Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#18	  emission model for Period B(MH+15, ApJ)#
mm-8

one-zone leptonic model: BLAZAR (Moderski+2003)#
GeV

ERC
48
SSC-1

log10 i Li [erg s ]SYN-2-1MeV

49-9log10 i Fi [erg s cm ]

keV

µm

-1047-1146

B1
B2
D1D2-12-131012141618log10 i [Hz]2022452426

1. Gamma-ray emission site should be inside BLR (< 0.1 pc)#
– efficient cooling at 100 MeV for 2hr variability#

2. very matter dominated jet: LB/Ljet ~ 10-4#
3. hard index (γ-ray band) in the fast cooling regime #– required very hard index for electron injection spectrum: p=1 #Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#19	  emission model for Period B(MH+15, ApJ)#
mm-8

one-zone leptonic model: BLAZAR (Moderski+2003)#
GeV

ERC
48
SSC-1

log10 i Li [erg s ]SYN-2-1MeV

49-9log10 i Fi [erg s cm ]keVµm-1047-1146

B1
B2D1D2-12-131012141618
log10 i [Hz]2022452426

1. Gamma-ray emission site should be inside BLR (< 0.1 pc)#– efficient cooling at 100 MeV for 2hr variability#

2. very matter dominated jet: LB/Ljet ~ 10-4#
3. hard index (γ-ray band) in the fast cooling regime #– required very hard index for electron injection spectrum: p=1 #Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#20	  Regions of AGN Jet Propagation
Jet Launching
RegionModified from Graphic
courtesy David Meier

Jet Collimation Region(10 –100 × Launching Region)~102.5±0.5 rS 	  Alfven Point

High speed spine

SlowMS Point
Poynting Flux Dominated

CD Unstable
Magnetic Helicity
Driven Region

SheathModified FastPoint

Fast MS Point
Collimation
Shock

Combined CD/KH
Unstable Region

Kinetic Energy Flux Dominatedwith Tangled (?) Field

KH Unstable Velocity Shear Driven Region

slide from Yosuke Mizuno!
Jan. 14, 2016 CTA-Japan workshop#Masaaki Hayashida (ICRR, U. Tokyo)#21	  Poynting flux dominated?
Kinetic energy flux dominated?
• if jet is derived by the magnetic field(e.g., Blandford-Znajek process) ,,,,#

à jet should be Poynting-flux dominated jet < 103 rg (= inside BRL)#• Leptonic models can explain well the broad band SED inside
BLR (0.03 pc < 103 rg for 5x108 Msolar)#– the emission model results suggest kinetic energy dominated jets
(some models with equipartition
see e.g., Dermer+14, ApJ, 782 for 3C 279)#• Hadronic models require stronger magnetic fields (10-100 G)
than the Leptonic models (0.01-1 G), but also requiresvery high power of relativistic protons, 1050 erg/s(e.g.,Zdziarski & Boettcher 15)#

Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#22	  Ue(±)/UB at the jet base of M87(Kino+14, ApJ, 786,5, Kino+15, ApJ, 803,30) #based on Synchrotron-self absorption#

Allowed B, γmin region(Lj=5x1044 erg/s, p=3)#43GHz#
core detection:#θthick<40µas(at 230 GHz)#

numbers: log(Ue/UB)#(Hada+13)#

Jan. 14, 2016 CTA-Japan workshop#

 UB >> Ue(±)!
(See also Nalewajko+14, ApJL, 796) #23	  emission model for Period B(MH+15, ApJ)#
mm-8

one-zone leptonic model: BLAZAR (Moderski+2003)#
GeV

ERC
48
SSC-1

log10 i Li [erg s ]SYN-2-1

MeV49-9log10 i Fi [erg s cm ]keV

µm-1047-1146

B1B2D1D2-12-13
1012141618log10 i [Hz]2022452426

1. Gamma-ray emission site should be inside BLR (< 0.1 pc)#– efficient cooling at 100 MeV for 2hr variability#

2. very matter dominated jet: LB/Ljet ~ 10-4#
3. hard index (γ-ray band) in the fast cooling regime #– required very hard index for electron injection spectrum: p=1 #Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#24	  hard (p<2) electron index
p : injected electron index#p ≥ 2: normal standard shock (Fermi-I) acceleration

too soft!!!
magnetic reconnection#
Our result:!
jet magnetization: σ < 10-3#• the reconnection will efficiently
work in this condition?!
• very localized acceleration(e.g., Guo+14, PRL)# sites?!
• can generate
1048 erg/s emission?!
à Stochastic Acceleration ?
(2nd order Fermi acceleration)(see Asano-san’s talk)!
(Giannios+09)#

Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#25	  3C 279 γ-ray activity for 7 years
250
2002015 June

Fermi-LAT: > 100 MeV(1 day bin)preliminary

150
100
50
00500

Flux ~2.5 x10-5 ph cm-2s-1

1000

Outburst during the ToO obs.

2000

4 month[MJD - 55000](>100 MeV in 1 day bin)
was recorded on 2015 June 16.
ToO observations started
at 2015 June 15 17:31:00

Jan. 14, 2016 CTA-Japan workshop#

1500

250

preliminary

200
1501005002120

2140

Masaaki Hayashida (ICRR, U. Tokyo)#

2160

2180

[MJD - 55000]

2200

2220

2240

26

Summary & Conclusion• Blazar 3C 279 showed outbursts (>10-5 ph/cm2/s) in last years#– 2013 Dec.: orphan γ-ray flare, very hard index (Γγ~1.7 )#– 2015 Jun.: the largest flare with minute-scale variability #• where is the gamma-ray emission site?#– inside BRL (~100 rg) for vary fast variability at 100 MeV!
– Jets should be sufficiently accelerated (Γ>50) even at < 100 rg!

• what is the dominant component in jet?#– emission model : kinetic-flux dominated : LB/Ljet ~ 10-4#– jet simulation: Poynting-flux dominated (< 103 rg)!
– radio observation (SSA): Poynting-flux dominated (M87 at ~a few rg)!

• what is the acceleration mechanism?#– not only shock accelerations should work (e.g., Fermi-II, reconnection)!
Jan. 14, 2016 CTA-Japan workshop#

Masaaki Hayashida (ICRR, U. Tokyo)#27