1 / 22

Acceleration and Energy Transport in the AGN jets: from sub-pc to kpc scale

<outline>. - Acceleration site in the universe. - Acceleration [1] : inner jets < sub-pc jet >. Acceleration [2] : outer jets < kpc jet >. K et al , 2001, ApJ, 560, 659 , 2002, MNRAS, 336, 932. - Energy transport along the jet. - Conclusion. , 2003a, A&A, 399, 91.

dewitt
Download Presentation

Acceleration and Energy Transport in the AGN jets: from sub-pc to kpc scale

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

  2. Cosmic-ray spectrum E < 1015.5 eV - Galactic origin - SNRs ? • Evidence for acceleration • up to 10-100 TeV E > 1015.5 eV - Extragalactic origin ? g mc2 Larmor-radius : RL = < system size eB Emax [TeV] ~ 103 R [pc] B [mG] (R: system size, B: magnetic field) Bamba et al. 2003

  3. Acceleration sites in the universe Extra-galactic site: AGN (sub-pc), AGN (kpc, HS, lobes), galaxy clusters, andg-ray bursts… Acceleration in AGNs? Hillas 1984 - typical power : 1044 [erg/s/AGN] - number density : 10 -7 [AGN/Mpc3] 1012 G Neutron Stars White Dwarfs 106 G AGN (inner) SUNSPOTS magnetic field : B 1G Magnetic stars AGN (outer) “Almost equal to the energy density of CRs above the knee” (Gaisser 2000) Galaxy clusters Interpl. Space SNR 1 mG Gal disc & halo 1km 1pc 1Mpc size : R

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

  5. Inner-jet : “Blazar”-region - Rapid time-variability as short as 1 day D ~ ctvarG 2BLK ~ 1017cm (sub-pc) - Spectral Energy Distribution from radio to TeV g-ray acceleration up to 1012 eV Takahashi et al. 2000 Mrk 421 TeV g Mrk 421 Inverse Compton synchrotron RXTE (8-15keV) ASCA(0.5-7keV) SAX EUVE optical X-ray GeV-g radio TeV-g 1 day

  6. Acceleration mechanism in sub-pc jet X-ray/g-ray BLR cloud BLR cloud G 1+2 G1 1017-18 cm (sub-pc) G2 G1 G2 - Central black-hole mass: 109 M • Central engine intermittently expels blobs of material, • which collide at D~ GBLK2 Rg ~ 1017-18[cm] - Physical parameters from temporal/spectral studies : B~ 0.1 G, R~0.01pc, gmax~ 106

  7. 20l(g)c  g , where l(g) = xRL tacc(g) = 3vs2 1.4x108 d101/2B0.1-1/2 x-1/2 bsh g max ~ gmax mec2 ~ 70 TeV “Theoretical limit” in the sub-pc jet Max Energy gmax ? (RL : Larmor radius) 3 mec tcool(g)=  g-1 4(uB + usoft)sTg if “tcool= tacc at gmax” & “synchrotron dominated” nsync ~ 2.5x1021 d10 x-1 bsh2 10 MeV (indep. on B)

  8. Kubo et al. 1998 Extreme Blazars- Detectable with CANGAROO? • High-freq blazars have low • luminosities : nsync∝Lsync-1.5 • High-freq blazars also have low • Comp/sync ratio: LC/Ls  1 Mrk 501 flare • Assuming z = 0.03 • (c.f., Mrk 421 & 501), • we expect • Fn(@1TeV) • ~ 10-13 ph/cm2/s • … still difficult to detect ? Ghisellini 1998

  9. Outer-jet: “kpc-region” • Many AGNs show flat radio-optical spectra: • evidence for “accelerated” particles • To resolve kpc-jet in z=0.1 AGN, Dq < 0.5’’ is necessary • Chandra has resolved >20 of X-ray jets in AGNs 3C273 M87 PKS0637-752 PKS1127-145 Cen A Cyg A pictor A

  10. Ex 1: Hotspot in 3C 303 • 15 ksec observation by Chandra in March 2001 • “X-ray hotspot” was detected at 9.6 s level (92 photons) • hotspot and bgd-QSO (z=1.6) were clearly resolved X-ray (Chandra: 0.4-8 keV) Radio (VLA; 1.5 GHz) 36 kpc (projected) bgd QSO nucleus knots Hot Spot Hot Spot K et al. 2003a

  11. Emission mechanism of 3C 303 hotspot • X-ray flux is well below the rad-to-opt continuum Inv Compton origin • Synchrotron self-Compton (SSC) dominates: • usync ~ 2×10 -12 [erg/cm3] ~ 3x uCMB LX usync + uCMB < uB Lsync B < 28 mG SSC synchrotron Synchrotron peak at 1014 Hz < nmax ERC (CMB Compton) gmax > 2x106 Best fitting parameter: B = 4.3mG, gmax =1.4x107

  12. Ex 2: X-ray jet and lobes in 3C 15 Jet Profile X-ray (Chandra: 0.4-8 keV) 1’ lobes Kataoka et al. 2003b K et al.2003b - FRII radio galaxy at z = 0.0730 (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

  13. Broad-band spectrum of jet and lobes kpc-jet (knot-C) Radio lobes nFn (erg/cm2/s) Frequency (Hz) Frequency (Hz) kpc-jet lobes - magnetic field B : 240 mG4 mG - Max Energy gmax: 2×1071×106? - Ratio Ue / UB: ~ 1?~2×103 - Jet power Ljet:3×1044 erg/s - Lobe ene Elobe:9×1059 erg

  14. Fueling time of the jet ? tfuel ~ Elobe/Ljet ~ 8×107 yrs Consistent with the “source age” of the radio lobes: tsrc ~ 2.1×107 (0.01 c / vexp) yrs Thermal/non-thermal pressure balance? - Plobe, thermal ~ 1.9 ne,th kT = 8.1×10-12 erg/cm3 - Plobe, non-th ~ 1/3 (Ue + UB) = 3.8×10-10 erg/cm3 Plobe, thermal < Plobe,non-th But, how to confine non-thermal electrons? More samples are awaited!

  15. M87 jet Marshall et al. 2003 108 B100m-1/2 d1-1/2 g max ~ Ex.3 M87: Ultra particle accelerator ? - nsync ~ 1.2x106 B gmax2 ~ 1018 [Hz] - Assuming ue = uB, we expect B ~ 100 mG ( This would be larger if ue > uB )

  16. 500 TeV kpc jet (knot/hot-spots) M87 3C303 3C15 sub-pc jet (Blazar AGNs) 1 TeV Max electron E 5 GeV 1mG 1G 1mG Magnetic field B Kpc-scale Jets: a Cosmic-ray booster? K et al. 2004, in prep - kpc-jet Knot Hot spot - sub-pc-jet × TeV blazar Low freq BL Lac Quasar Hosted Blazar

  17. blazar heart in “Cen-A” “Blazar Heart” in Radio Galaxies FR-I ⇔BL Lacs FR-II ⇔ OVV quasar blazars BLRG • Blazar core in Radio gal should be • much fainter, since ∝ d-4 - SED can be fit by “blazar parameters”, except for beaming factor of d ~ 2 Radio Gal. BH Chiaberge et al. 2001

  18. SED of sub-pc jet (3C 273) Beamed- synchrotron Beamed SSC or ERC Non-beamed blue bump nHE Sub-pc jet & nucleus of 3C 273 • 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 K et al. 2002

  19. Kpc-jet of 3C273 (by Chandra) Sambruna et al. 2001 ~ 50 kpc (projected) A B C D • Kpc-jet luminosity is ~ 10- 3 of sub-pc jet • X-rays are likely due to the inv. Comp of CMB photons

  20. Sub-pc vs kpc jet power sub-pc 10-kpc R (region size) 0.01 pc 1500 pc B (Magnetic field) 0.4 G 1.9×10-6 G N (no. density) 1.0×105 /cm3 8.1×10-3 /cm3 2.0×103 6.0×106 gmax (Max ene) Lkin (Jet power) >1.3×1047 erg/s 4.0×1045 erg/s • about 100 times of “visible” kinetic energy may be • hidden at the bottom of the jet (sub-pc).

  21. Ethermal 1 10-2 Electron No density 10-4 10-6 10-8 E non-thermal 106 1 10 102 104 105 103 Electron Lorentz factor Why Lkin, kpc > Lkin, sub-pc ? - In sub-pc, only less than 1% of electrons are picked up into shock acc. process (internal shock : see Tanihata et al. 2003) - 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)

  22. Conclusion Not only sub-pc scale jet, but also kpc-scale jets are one of the most powerful accelerators in the universe. • There may be hidden “blazars” of Emax ~ 70 TeV (acc limit) • Some radio galaxies actually accelerate particles • up to Emax > 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” ? • Need more sample, but apparently similar to GRB

More Related