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On AGN jets: my concerns

On AGN jets: my concerns. M. Kino (ISAS/JAXA). Osaka univ. 21. Dec 2007. Outline. Introduction Cosmic bubbles; Remnants of AGN jets Emissions from shocked-ICM-shell (Ito +) Cygnus A viewed in X-ray (Yaji + ) 3. Inner core jets VSOP-2 and VLBA M87.

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On AGN jets: my concerns

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  1. On AGN jets: my concerns M. Kino (ISAS/JAXA) Osaka univ. 21. Dec 2007

  2. Outline • Introduction • Cosmic bubbles; Remnants of AGN jets • Emissions from shocked-ICM-shell (Ito +) • Cygnus A viewed in X-ray (Yaji + ) 3. Inner core jets • VSOP-2 and VLBA • M87

  3. Introduction: Internal-external shock scenario for AGN jets Fig: Piran 2003 Blazars (< 1pc) Radio-lobe, cocoon, Hot-spots (100kpc~1Mpc)

  4. Introduction: kpc ~ Mpc scale view • We present our recent studies on • Shell emission (Ito+) • Cygnus A viewed in X-ray • (Yaji+) Cocoon • Previous meeting, we present our studies on cocoon • Dynamics (Kino+05; Kawakatu+06) • MeV-gamma cocoon (Kino+07) • Plasma composition (Kino+ in prep) Shell Fig. credit; CXC

  5. On emission from shocked shell of AGN Ito H. Doctor thesis (2008) Ito, Kino, Kawakatu & Yamada (2008) in prep

  6. Why we can’t see the shells? • Sub-sonic expansion. However, at least, some of bubbles seem to have strong-shocks. (Cen A; NGC 3081; Cygnus A) • Electron acceleration efficiency is low? (a hint to electron acceleration mechanism?)

  7. Dynamics of shell-expansion Using a spherical-shell approximation (e. g., Ostriker & McKee 1988) Jet remnant (cocoon) Shell of shocked ICM

  8. Evolution of synchrotron spectra • We assume e acceleration efficiency is constant in time. Larger => brighter • Gamma_max is given by age limit (t_acc=t) for younger bubble older => larger syn. cooling limit (t_acc=t_syn) for older bubble older => slower => smaller • Gamma_br is estimated t_syn= t older => smaller

  9. Evolution of synchrotron spectrum(injection index s=2) Young source Old source

  10. Typical snapshot Xi larger Extremely low ε? Is this consistent with standard DSA? Bohm-limit Cygnus A lobes

  11. A discovery of “X-ray shell” in Cen A (Kraft +)

  12. Various patterns for “bubble & ICM” emission Dense ICM Dilute ICM Cocoon-dominated Cocoon-dominated (3C452, Fornax A) Cavity (Perseus and many others) shell-dominated

  13. UHECRs from Cen A shell? omache E_max~ 10^18 eV (Z/xi) (R/1kpc) (B/10microG) In order to produce UHECRs B~1mG at the shell is required. Is it possible?

  14. A detection of Non-thermal X-ray emission from Cygnus A lobes? Yaji Y. Y., Master thesis (2008) Yaji, Isobe, Tashiro, Kino, Asada, Nagai, Kusunose & Seta (2008) in progress

  15. Hardness ratio of Cygnus A(7-10keV / 5-7keV) Does the cocoon region show “harder” spectrum than the external Intra-Cluster Medium’s one? What’s the origin? Preliminary

  16. A cartoon of Background ICM subtraction Line of sight Background ICM

  17. Power Law component exists!

  18. Non-thermal spectra@ Cygnus A lobes Preliminary

  19. Action Items • Error estimate on the fig. of “hardness-ratio” • Check the case of different Background-ICM • Non-thermal electron vs. B-fields (seed-photon for Inv.Compton is probably U_syn!) • MEKAL thermal component is due to “lobes” or “compressed ICM”?

  20. Aiming for … Consistent understanding of the whole system: Jet Hot-spots Cocoon, lobes Shell ICM Robust constraints on the “central-engine” will be surely obtained.

  21. 2. Inner core jets • On VSOP-2; on VLBA situation • M87 (Based on Walker’s talk@VSOP2symposium)

  22. International Collaboration on VSOP‐2 JVN/EAVN JPL/NASA NRAO DRAO/CSA EVN/JIVE ATNF, etc. 絶対に必要なパートナー かつ 強力なライバル

  23. Save VLVA!2011 to be closed VLBA (The Very Long Baseline Array)とは？アメリカにあるVLBI（超長基線電波干渉計）専用の望遠鏡群。口径25mの電波望遠鏡１０台をその国土、ハワイからプエルトリコまで差し渡し８千kmに配置して干渉計を構成、口径８千km相当の大電波望遠鏡. VLBA問題とは？米国予算のより大型の天文プロジェクトへの振り分けのために、上記VLBAが2011年をもって閉鎖される危機に瀕しているという問題.

  24. 周辺の動向 ■VLBA周辺研究者は近年、VLBA閉鎖問題を乗り切るため、ブレーザージェットに対して、GLASTとのコラボレーションを精力的に計画。 From Taylor’s PPT http://glast.gsfc.nasa.gov/science/resources/meetings/lat/agn_april07/program.html

  25. Japan-US International VSOP-2 Key Science Meeting (21-23 October 2007 国立天文台)目的：VLBAを救う予算獲得 09:00-09:30 Outline of Japanese KSPs - Kameno - AGN, Maser, YSO magnetosphere 09:30-10:00 Preliminary Korean KSPs - Sohn 10:30-12:00 AGN KSP discussions - JPN AGN KSP AGN in general - Kameno - Blazar - Kino - Potential U.S.-led AGN KSP - Taylor 01:00-02:30 Megamaser KSP discussions - JPN Megamaser KSP - Hagiwara - Potential U.S.-led megamaser KSP - Greenhill 02:30- How do US and Japanese KSPs fit together, discussion on how to work out the details - All 「日」と「米」提案 内容がかぶってる

  26. ? New prospects on blazars ブレーザーの図　 0.01pc scale observation by ＶSOP2 ＶＳＯＰ２空間分解能だと、近傍のTeV blazar Mrk 421, Mrk 501などは、1Zone modelと ほぼ同じ空間スケールに届く！ 高エネルギー 放射領域　 “見えない”部分が、“見えて”きた。 ~internal shock model for blazars~ Kino & Takahara (2008), MNRAS “見えない” 噴出塊 VSOP-2 sci. working groupでも、blazarをKey Sci. Programの候補として検討がkick off した。興味ある方の参入、大歓迎です！

  27. Spine-sheath blazar?? omache

  28. SUBLUMINAL MOTION • Many VLBI observations show slow motions • VLBA < 0.1c (Biretta & Junor 1995; Junor & Biretta 1995) • VSOP No motions (Dodson et al 2006) • VLBI 1.6 GHz 0.28c (Reid et al 1989) • VLBA 43 GHz 0.25-0.40c (Ly et al 2007) • Perhaps best case is 15 GHz monitoring (Kovalev et al. 2007) • A few percent of the speed of light • Sampling interval 5±3 months • Slow material or patterns, perhaps from instabilities?

  29. SUPERLUMINAL MOTIONS • VLA Typical 0.5 c, but up to 2.5c (Biretta et al 1995) • HST-1 Optical with HST (Biretta et al 1999) • Knot at 0.9” (70pc projected) Speeds ~5-6 c • HST-1 VLBA 20cm(Cheung et al 2007) • Speeds 2.5 - 4.5 c. • Feature near core slow • HST-1 Plausible site for TEV emission

  30. Possible site of TEV emission (Cheung et al 2007) HST-1 FLARE Harris et al. 2007

  31. M87 43 GHz Images at ~1 yr Intervals Our old observations and archive data. Mostly from use of M87 as phase reference source. (Ly, Walker, & Junor, 2007, Ap. J. 660, 200.) • Rates 2001.78 - 2002.42 are 0.25 - 0.40c • 1.0 to 1.7 mas/yr • Other epochs too widely spaced • Feature seen east of core • Counterjet, inner jet or disk? • If counterjet, speeds and brightness can give orientation • Basic edge brightened structure maintained • Dominant edge shifts from south to north

  32. Day 0 Day 13 Day 3 Day 35 Day 10 Day 97 PILOT PROJECT No PT • To determine movie frame rate: • VLBA 43 GHz 2006 • 10hr observations, 128 Mbps, full polarization • Good consistency between close epochs • Motions near 2.2 mas/yr (0.6c) at 1.5 mas from core • About 1.5 mas/yr near core • Superluminal motions not seen • Feature east of core still seen Beam: 0.42x0.18 mas 0.2mas = 0.016pc = 60Rs 1mas/yr = 0.25c

  33. Higher Resolution: M87 at 86 GHz • Global VLBI • Starting to resolve high opening angle region • Krichbaum et al 2007 • Data from Apr 2004 • Beam 0.20 x 0.066 mas • Peak 0.38 Jy • Lowest contour 1.1 mJy 1mas=300Rs

  34. Summary of inner-core jets The AGN jet@vicinity of “central engine”(M87 & blazars) 1. How to explain the velocity-profile? (slow TeV blazars and fast EGRET blazars; sub-luminal near core and superluminal outside) 2. How to connect “internal shock”, “spine-sheath” and “conical-standing shock”?

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