Systematic Study of TeV detected BL Lacs:
Jet Energetics andParticle Acceleration Eﬃciency
in the Blazar Zone
Yoshiyuki Inoue(JAXA International Top Young Fellow)
Collaborators: Yasuyuki T. Tanaka

The extreme Universe viewed in very-high-energy gamma-rays 2015, Kashiwa, 2016-01-14

Systematic Study of Blazars• What is AGN jet energetics?
• Fermi allows us systematic study• Prad ~ 0.1 Pjet (Ghisellini+’14)• but, only luminous blazars
The Astrophysical Journal, 736:131 (22pp), 2011 August 1

Ghisellini+’14-810Figure 1: Extended Data Figure 1:

Jet power vs radiative jet power. We compare
the total -9
jet power and the radiative one for the blazars in our sample. The yellow lines,
10 correspond to equality and to Pjet equal to 10–fold and 100–fold Prad . Sameas labelled,
symbols as in Fig. 1. The average error bar is indicated.

-111015-121010-14• based on phenomenological➡ physically connected parameters.

-13

10

data: the model describes very satisfactorily the entire measured
broadband SED. The model goes through the SMA (225 GHz)
data point, as well as through the VLBA (43 GHz) data point
for the partially resolved radio core. The size of the VLBA
core of the 2009 data from Mrk 421 at 15 GHz and 43 GHz
is ≃0.06–0.12 mas (as reported in Section 5.1.1) or using theconversion scale 0.61 pc mas−1 ≃ 1–2 ×1017 cm. The VLBA
size estimation is the FWHM of a Gaussian representing thebrightness distribution of the blob, which could be approximatedas 0.9 times the radius of a corresponding spherical blob
(Marscher 1983). That implies that the size of the VLBA core iscomparable (a factor of about two to four times larger) than thatof the model blob for tvar = 1 day (∼5 × 1016 cm). Therefore,
it is reasonable to consider that the radio flux density from theVLBA core is indeed dominated by the radio flux density of theblazar emission. The other radio observations are single dishmeasurements and hence integrate over a region that is ordersmodels: e.g. 12 parameters for Mrk421.

-1010-1-2

νFν [erg s cm ]Mrk 421

Abdo et al.

➡ HBLs: MAXI, BAT, LAT, IACTs

8101110101417102010ν [Hz]102326101029Abdo+’11

Particle Acceleration Eﬃciency
neutron starpr• Are AGN jets eﬃcient particle

otFewhitedwarf

on

10 20eV10 20eVaccelerators?
AGN

AGN jets
GRB

hot spots• primary candidates for UHECR

acceleration sites.

SNR
IGM shocks

Kotera & Olinto ‘11• But, particle accelerationeﬃciency is not well understood.

Figure 11:
Updated Hillas (1984) diagram. Above the blue (red) line protons (iron nuclei) can be confined toa maximum energy of Emax = 1020 eV. The most powerful candidate sources are shown with theuncertainties in their parameters.

for extragalactic sources. Requiring that candidate sources be capable of confining particles up to Emax , translates into a simple selection criterium for candidate sources withmagnetic field strength B and extension R (Hillas 1984): rL  R, i.e., E  Emax ⇠1 EeV Z (B/1 µG)(R/1 kpc). Figure 11 presents the so-called Hillas diagram where candidate sources are placed in a B R phase-space, taking into account the uncertainties
on these parameters (see also Ptitsyna & Troitsky 2010 for an updated discussion on theHillas diagram). Most astrophysical objects do not even reach the iron confinement line
up to 1020 eV, leaving the best candidates for UHECR acceleration to be: neutron stars,
Active Galactic Nuclei (AGN), Gamma Ray Bursts (GRBs), and accretion shocks in theintergalactic medium. The Hillas criterion is a necessary condition, but not sufficient. In
particular, most UHECR acceleration models rely on time dependent environments andrelativistic outflows where the Lorentz factor
1. In the rest frame of the magnetizedInoue & Takahara ‘96• Past SED fittings suggested low

eﬃciency (η~105; Inoue & Takahara’96, Sato+’08, Finke+’08).
• But, not simultaneous data andno systematic studies.

TeV Blazar Sample
E2dN/dE [TeV/cm2/s]

10-7
10-8
10-9-10
10
10-11
10-12
10-13-7
10
10-8
10-9
10-10-11
10
10-12
10-13-7
10
10-8
10-9
10-10
10-11
10-12-13
10

1ES 1215+303
z = 0.130

1ES 0806-524
z = 0.138• Select 36 blazars with z

1ES 0229+200z = 0.14

1RXS J101015.9 - 311909 H 2356-309
z = 0.142639
z = 0.165

from the default TeVcat
catalog.
• 3FGL SED data.

RX J0648.7+1516
z = 0.179• Low-state data are

available for 31/36.
1ES 1218+304
z = 0.182

1ES 1101-232
z = 0.186

1ES 0347-121
z = 0.188• 13 HBLs have BATdata.
-4-3-2-1

0

1 -4-3-2-10

1 -4-3-2-1

0

10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10Energy [TeV]
Energy [TeV]
Energy [TeV]1• CIB correction by YI

YI & Tanaka, in prep.

+’13.

Emission Modeling• One-zone synchrotron self Compton (e.g. Finke+’08)• Beaming factor “δ” = bulk Lorentz factor “Γ”• Angular size of the blob “θ” = the jet opening angle “θj”
• Γθj = 1 -> θ = 1/δ
• Assume spherical emitting plasma at r = 1000 rs from BH.
• ~1 day variability for MBH = 109 Msun & δ = 10.

Electron Distribution• Assume diﬀusive shock acceleration.
• broken-power law plus hyper-exp cutoﬀ
Ne0 ( 0 ) = Ke b0p1

✓◆
0 p10b+✓◆0 p20b1exp" ✓#◆20c• It should be p2 = p1 + 1. But, photon spectrum steeping can besteeper in inhomogeneous fluid (e.g. Reynolds ’09).
• By setting p2 as a free parameter, we phenomenologically consider

inhomogeneity of the emission region.
• cooling break : syn. + SSC cooling = dynamical time.
• maximum Lorentz factor : acc. time = syn. + SSC cooling.
• minimum electron Lorentz factor is set by shocked thermal protonenergy.

How to find parameters
10-8• Free parameters are• Ke, p1, p2, B, δ, ηg

E2dN/dE [erg/cm2/s]

10-910+-4

Syn + SSC (e +e , d=10 )1ES 1959+650 Syn + SSC (p+e++e-, d=104)
Syn + SSC (p+e++e-, d=100)
Data
NED-10

10-11
10-12
10-13
10-14 -4
10

10-2100

102

104 106 108
Energy [eV]1010 1012 1014

• Global fit to low-state data but not including errors.
• Then, perform fit to BAT data including errors setting

only ηg as a free parameter.

E2dN/dE [erg/cm2/s]

Spectral Fitting Results

E2dN/dE [erg/cm2/s]

Mrk 501

1ES 2344+514

1ES 1959+650

PKS 0548-322

PKS 2005-489

RGB J0710+591

14 -2 010-2100 102 104 106 108101010121010
10 102 104 106 108101010121014
Energy [eV]
Energy [eV]

10-10
10-11
10-12
10-13
10-10
10-11
10-12
10-13

E2dN/dE [erg/cm2/s]

Mrk 421

10-10
10-11

best fit
dg=1
10-12
amin=1-13
10
10-2100 102 104 106 108101010121014 MAXI/GSC
Energy [eV]

Swift/BAT
Fermi/LAT
IACTs
NED
YI & Tanaka, in prep.

E2dN/dE [erg/cm2/s]

Spectral Fitting Results
1ES 0229+200

H2356-309

1ES1218+304

1ES 1101-232

1ES 0347-121

10-10
10-11
10-1210-13E2dN/dE [erg/cm2/s]

H1426-428

10-10
10-11
10-12
10-13-202468101214 -202468101214 -202468101210 10 10 10 10 10 10 10 1010 10 10 10 10 10 10 10 1010 10 10 10 10 10 10 10 10Energy [eV]
Energy [eV]
Energy [eV]best fit
dg=1
amin=1
MAXI/GSC

14

Swift/BAT
Fermi/LAT
IACTs
NED
YI & Tanaka, in prep.

Electron Distribution
Electron Distribution

Index Relation

21053

1052

1051

1050
10491048
1047

54.5
Mrk 421
Mrk 501
1ES 2344+5141ES 1959+650
PKS 0548+322
PKS 2005-489
RGB J0710+591
H1426-428
1ES 0229+200
H2356-309
1ES 1218+304
1ES 1101-232
1ES 0347-121

3.5

100Our Sample
Homogeneous Radiative Cooling
Relativistic Shock

2.5
210-1

PKS 2005-489

31046
1045 -2
10H1426-428

4p2

ae dN/da1054

101102
103
104
Lorentz Factor ae105

106

107

108

1

1.5

2

2.5
p1

3

3.5

4

YI & Tanaka, in prep.

• Most objects show p1 ~ 2.2 which is expected for relativistic shocks(e.g. Kirk+’00, Keshet & Waxman ’05, Sironi+’15)• However, p1 ~1.6 is required for H1426-428. Stochastic acceleration?
• Some are consistent with homogeneous radiative cooling (p2 ~ p1+1),

but others not. Due to inhomogenity in the source?

Jet Energetics of HBLs
10

Pe vs PB

44

10Pjet vs Prad

44

Prad [erg/s]

PB [erg/s]

1043

1042

1041

1040 42
10Our Sample
PB = Pe (Equipartition)
PB = 10-1
P-2 e
PB = 10 Pe
1043

1044
Pe [erg/s]

1045

1046

1043

1042

1041 43
10Our Sample
Prad = 10-1
P-2 jetPrad = 10 Pjet
1044
1045Pjet = PB + Pe + Pp [erg/s]

1046
YI & Tanaka, inprep.

• All of our samples are near equipartition: PB ~ 0.1 Pe• Assuming cold protons only, radiative eﬃciency is 0.06.
• similar to FSRQ samples (Ghisellini+’14)

marginally consistent with those studies.
rived jet power here and Nemmen et al.
etal.
(2014)
isalowerlimit
becausethePjet vs LEdd
not be constrained currently without assumels (e.g. Aharonian 2000; Mücke & Proth
PB + Pp ,(21)the ratio can be smaller than we estimated
10processes are inefficient radiation mechan
Pjet here is the lower limit of2009; Zdziarski & Böttcher 2015).
l proton energy can not be esFigure 8 shows the ratio between Pjet and10, the minimum proton energy
ratio is < Pjet /LEdd >= 1.4 × 10−3 with a sta
Our Sample
P −4= 10L
6.5×10. Accretion
rate in BL Lacs is k101010
1010max
asin
theradiative-inefficientaccretion flo′ ′ ′L[erg/s]YI&Tanakain
prep.
dγ Ne (γe ), -3(22)which is sometimes called as advection do• Pjet ~ 10 LEdd
flow (ADAF). The mass accretion rate ofTheone
massproton
accretionof HBLsorder
is about
only •andperrate
radiof ṁ ≃ 1.2 × 10−2 (Wang+’02).
of the Eddington mwith radiative efficiency of ϵ = 0.1 (Wang

can be the energy carrier ofrrelated because of negligible
d lower magnetic field power.
10yAccretion vs Jet
45

Pjet [erg/s]

44

43-3jet

4245

46

edd

4748

edd

• ~0.1% of accreted mass loaded on the jet in HBLs.

• But, ~100% mass loaded in the case of FSRQs (Ghisellini+’14)• RIAFs inevitably generate outflows ejecting ~30% of mass as a disk wind(Blandford & Begelman ’99; Totani ‘06)

Acceleration Eﬃciency
Pjet vs Ep,max

1016

1016

1015

1015

Ep, max [eV]

Ep, max [eV]ηg vs Ep,max

1014

1013 31015

Our Sample
104
dg

1014

105

1013 4210

Ep,max = 10(Pjet/1044

1043

Our Sample[erg/s])1/2 [eV]1044

Pjet [erg/s]

1045

YI & Tanaka, in prep.

• HBLs are not eﬃcient accelerators having ηg ~ 104.
• We have PB ~ 0.06
Pjet. Then, the maximum proton energy
scan be2e⌘g✓◆fB Pjetc◆1/2 ✓◆1/2 ⇣✓Pjet⌘g ⌘ 1fB
15[eV].
' 1 ⇥ 100.06
1044 erg/s
104

Ep,max =1ES 0229+200
1ES 0229+20010-8

2

2E dN/dE [erg/cm /s]

10-910-10

Syn + SSC (e+++e--, d=1)
1ES 0229+200 Syn + SSC (p+e +e , d=1)
Syn + SSC (p+e+++e- -, d=10)
Syn + SSC (p+e +e , d=104)
DataNED• Very hard HBL• 3FGL data shows a softspectrum at GeV band.

10-1110• this comes from-12

Synchrotron emission?

10-13
10-14 -4
1010-2• A possible contamination:
100

102104 106 108 1010 1012 1014
Energy [eV] YI & Tanaka in prep.

• Sun & moon occultation?

Summary• Systematic spectral study of 13 TeV HBLs using MAXI, BAT,LAT, & IACTs data under the DSA scenario.
• PB ~ 0.1 Pe• Prad ~ 0.06 Pjet similar to FSRQs assuming cold protons

only.
• 0.1 % of accreted mass is loaded on to the jet.
• acceleration eﬃciency is ηg ~ 104.
• But 1ES 0229+200 can have ηg ~ 1. Caused by Sun &moon occultations?