Acceleration and Energy Transport in the AGN jets: from sub-pc to kpc scale Jun Kataoka Tokyo Institute of Technology - Acceleration site in the universe - Acceleration [1] : inner jets - Acceleration [2] : outer jets - Energy transport along the jet - Conclusion K et al, 2001, ApJ, 560, 659, 2002, MNRAS, 336, 932, 2003a, A&A, 399, 91, 2003b, A&A, 410, 833

Cosmic-ray spectrum E < eV - Galactic origin - SNRs ? E > eV- Extragalactic origin ? E max [TeV] ~ 10 3 R [pc] B [  G] (R: system size, B: magnetic field) Bamba et al Evidence for acceleration up to TeV Larmor-radius : R L = eB  mc 2 < system size

Acceleration sites in the universe Acceleration in AGNs? - typical power : [erg/s/AGN] - number density : [AGN/Mpc 3 ] “Almost equal to the energy density of CRs above the knee” (Gaisser 2000) AGN (inner) White Dwarfs Neutron Stars SUNSPOTS Gal disc & halo Interpl. Space SNR AGN (outer) Galaxy clusters Extra-galactic site: AGN (sub-pc), AGN (kpc, HS, lobes), galaxy clusters, and  -ray bursts… Hillas km1pc1Mpc size : R G 10 6 G 1 G1 G 1  G magnetic field : B Magnetic stars

AGN with relativistic jet - Plasma outflows called “jet” have been observed (about 10 % of AGN) - Super-luminal motions imply jets are highly relativistic (  ~10 or  ~ 0.994) - Jet size ranges from ~0.1 pc to more than 1 Mpc ex. 3C46 (1.4 GHz) core (AGN) + inner jet knot lobe hot spot

Inner-jet : “Blazar”-region - Rapid time-variability as short as 1 day D ~ ct var   BLK ~ cm (sub-pc) - Spectral Energy Distribution from radio to TeV  -ray acceleration up to eV TeV  RXTE (8-15keV) ASCA(0.5-7keV) EUVE SAX 1 day radio opticalX-ray GeV-  TeV-  Mrk 421 synchrotron Inverse Compton Takahashi et al. 2000

Acceleration mechanism in sub-pc jet - Central black-hole mass: 10 9 M - Central engine intermittently expels blobs of material, which collide at D  ~  BLK 2 R g ~ [cm] - Physical parameters from temporal/spectral studies : B~ 0.1 G, R~0.01pc,  max ~ 10 6 BLR cloud BLR cloud       cm (sub-pc) X-ray/  -ray

“Theoretical limit” in the sub-pc jet Max Energy  max ?  sync ~ 2.5x10 21      sh 2  10 MeV (indep. on B) t acc  = 20  c 3v s 2 , where  R L t cool  = 3 m e c 4(u B + u soft )  T    (R L : Larmor radius) if “t cool = t acc at  max ” & “synchrotron dominated”  max ~ 1.4x10 8  10 1/2 B /2  -1/2  sh  max m e c 2 ~ 70 TeV

Extreme Blazars- Detectable with CANGAROO? - High-freq blazars have low luminosities : sync ∝ L sync -1.5 Kubo et al Assuming z = 0.03 (c.f., Mrk 421 & 501), we expect F ~ ph/cm 2 /s … still difficult to detect ? - High-freq blazars also have low Comp/sync ratio: L C /L s  1 Mrk 501 flare Ghisellini 1998

Outer-jet: “kpc-region” - Many AGNs show flat radio-optical spectra: evidence for “accelerated” particles - To resolve kpc-jet in z=0.1 AGN,  < 0.5’’ is necessary - Chandra has resolved >20 of X-ray jets in AGNs pictor A PKS C273 PKS Cen ACyg A M87

Ex 1: Hotspot in 3C ksec observation by Chandra in March “X-ray hotspot” was detected at 9.6  level (92 photons) - hotspot and bgd-QSO (z=1.6) were clearly resolved Radio (VLA; 1.5 GHz) X-ray (Chandra: keV) knots Hot Spot bgd QSO K et al. 2003a nucleus 36 kpc (projected) Hot Spot

Emission mechanism of 3C 303 hotspot - X-ray flux is well below the rad-to-opt continuum - Synchrotron self-Compton (SSC) dominates: u sync ~ 2× [erg/cm 3 ] ~ 3x u CMB LXLX u B < u sync + u CMB L sync B < 28  G Synchrotron peak at Hz < max  max > 2x10 6 Best fitting parameter: B = 4.3  G,  max =1.4x10 7 synchrotron SSC ERC (CMB Compton) Inv Compton origin

Ex 2: X-ray jet and lobes in 3C 15 - FRII radio galaxy at z = (1” = 1.25 kpc) - “optical/X-ray synchrotron jet” has been detected - Knot-C is the brightest (0.5 kpc FWHM ) in the X-ray band - “X-ray lobes” are clearly detected lobes Jet Profile X-ray (Chandra: keV) 1’ Kataoka et al. 2003b K et al.2003b

Broad-band spectrum of jet and lobes Frequency  Hz  F   erg/cm 2 /s  Frequency  Hz  kpc-jet (knot-C) Radio lobes - magnetic field B : 240  G 4  G - Max Energy  max : 2× × 10 6 ? - Ratio U e / U B : ~ 1? ~2 × Jet power L jet : 3×10 44 erg/s - Lobe ene E lobe : 9×10 59 erg kpc-jet lobes

Fueling time of the jet ? t fuel ~ E lobe /L jet ~ 8×10 7 yrs Consistent with the “source age” of the radio lobes: t src ~ 2.1×10 7 (0.01 c / v exp ) yrs Thermal/non-thermal pressure balance? - P lobe, thermal ~ 1.9 n e,th kT = 8.1× erg/cm 3 - P lobe, non-th ~ 1/3 (U e + U B ) = 3.8× erg/cm 3 But, how to confine non-thermal electrons? P lobe, thermal < P lobe,non-th More samples are awaited!

Ex.3 M87: Ultra particle accelerator ? M87 jet Marshall et al  sync ~ 1.2x10 6  B  max 2 ~ [Hz]  Assuming u e = u B, we expect B ~ 100  G  max ~ 10 8 B 100  -1/2    ( This would be larger if u e > u B )

Kpc-scale Jets: a Cosmic-ray booster? Knot Hot spot - kpc-jet TeV blazar Low freq BL Lac - sub-pc-jet × Quasar Hosted Blazar Max electron E Magnetic field B 1G1G 1mG 1G 5 GeV 1 TeV 500 TeV 3C15 3C303 sub-pc jet (Blazar AGNs) kpc jet (knot/hot-spots) M87 K et al. 2004, in prep

“Blazar Heart” in Radio Galaxies blazars BLRG Radio Gal. BH blazar heart in  “Cen-A” Chiaberge et al FR-I ⇔ BL Lacs FR-II ⇔ OVV quasar - Blazar core in Radio gal should be  much fainter, since ∝   - SED can be fit by “blazar parameters”, except for beaming factor of  ~ 2

Sub-pc jet & nucleus of 3C Typical blazar (super-luminal motion, rapid variability…), but “jet” and “acc. disk vicinity” are both visible. - Furthermore, kpc-jet is also resolved by HST & Chandra Beamed- synchrotron Beamed SSC or ERC Non-beamed blue bump HE SED of sub-pc jet (3C 273) K et al. 2002

Kpc-jet of 3C273 (by Chandra) - Kpc-jet luminosity is ~ of sub-pc jet ~ 50 kpc (projected) A B C D Sambruna et al X-rays are likely due to the inv. Comp of CMB photons

Sub-pc vs kpc jet power L kin (Jet power) N (no. density) sub-pc10-kpc  max (Max ene) R (region size) 0.01 pc1500 pc 1.0×10 5 /cm 3 B (Magnetic field) 8.1×10 -3 /cm 3 1.9×10 -6 G0.4 G 2.0× × ×10 45 erg/s >1.3×10 47 erg/s - about 100 times of “visible” kinetic energy may be hidden at the bottom of the jet (sub-pc).

Why L kin, kpc > L kin, sub-pc ? - In sub-pc, only less than 1% of electrons are picked up into shock acc. process (internal shock : see Tanihata et al ) E thermal Electron Lorentz factor Electron No density 10 3 E non-thermal - In kpc, most of electrons are accelerated efficiently when colliding with ISM (external shock : see Dermer 1998 ) Very similar to the relation Between GRB (int shock) and afterglows (ext shock)

Conclusion Not only sub-pc scale jet, but also kpc-scale jets are one of the most powerful accelerators in the universe. - Some radio galaxies actually accelerate particles up to E max > 10 ~ 100 TeV Only <1 % of bulk kinetic energy may be released in sub-pc, whereas most of its power released in kpc. - Different shock acceleration at work between sub-pc and kpc. e.g., “internal shock” and “external shock” ? - There may be hidden “blazars” of E max ~ 70 TeV (acc limit) - Need more sample, but apparently similar to GRB