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Extended X-ray Emissions from the Radio Galaxies Centaurus B and Fornax A

Extended X-ray Emissions from the Radio Galaxies Centaurus B and Fornax A. Makoto Tashiro 1 , Naoki Isobe 2 , Masaya Suzuki 1 Kouichi Ito 1 , Keiichi Abe 1 , and Kazuo Makishima 3 1:Saitama Univ., 2: ISAS/JAXA, 3:Univ. of Tokyo. XMM-Newton observation Centaurus B

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Extended X-ray Emissions from the Radio Galaxies Centaurus B and Fornax A

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  1. Extended X-ray Emissions from the Radio Galaxies Centaurus B and Fornax A Makoto Tashiro1, Naoki Isobe2, Masaya Suzuki1 Kouichi Ito1, Keiichi Abe1,and Kazuo Makishima31:Saitama Univ., 2: ISAS/JAXA, 3:Univ. of Tokyo • XMM-Newton observation Centaurus B • Summary diagrams of IC-X-ray observation from radio lobes • ASCA and Chandra observations of Fornax A ASCA (ISAS)

  2. un-ID source ((pow + ray) x Gal. Abs.) • Photon index: 2.65±0.31 • Temperature: kT = 0.14 keV • F(2-10keV): 0.3×10-13 erg cm-2 s-1 AGN (power-law x Abs.) - Photon index: 1.56±0.02 - F(2-10keV): 5.4E-12 ergcm-2 s-1 - L(2-10keV) :1.5E42erg s-1 • Whole & “diffuse” (Diffuse =power-law x Galactic Abs.) Photon index: 1.4±0.3 F(2-10keV):6.7E-13erg cm-2 s-1 L(2-10keV) :1.9E41erg s-1 Centaurus B with MOST (McAdam, 1991, Proc. Astron. Soc. Australia, 9 (2), 255) & ASCA (Tashiro et al. 1998, ApJ 499, 713) ASCA (ISAS) “diffuse” 1. XMM-Newton observation Centaurus B( radio: Jones, Lloyd, McAdam, 2001, MNRAS, 325, 817) • “jet” (power-law x Galactic Abs.) • Photon index: 1.43±0.18 • F(2-10keV): 2.0E-13 erg cm-2 s-1 • L(2-10keV) :5.6E40erg s-1 “Jet” Un-identified Point Source “arrowhead” (power-law x Galactic Abs.) - Photon index: 1.66±0.43 - F(2-10keV): 0.5E-13 ergcm-2 s-1 - L(2-10keV) :1.2E40erg s-1 nucleus “Arrow”

  3. X-ray flux un-ID source ASCA XMM “diffuse” “arrow” “jet” nucleus Gr ~ GX IC-X-ray XMM resultsin comparison with ASCA results(Tashiro et al. 1998, ApJ 499, 713) Lxnuc = 1.5×1042 erg/s Lxjet= 5.4 × 1040 erg/s Photon Indices Gr = 1.73 Gdiffuse= 1.4±0.3 Garrow = 1.66±0.43 Gjet = 1.43±0.18 Lxarrow =1.2 ×1040 erg/s Lxdiff =1.9 ×1041 erg/s uCMB > unucleus (d > 3 kpc (0.2’)) →CMB dominates both in the region “jet” (d~ 7.5 kpc) and “arrow” (d~45 kpc)

  4. ue: energy density of electrons um: energy density of magnetic fields V : Volume of the Lobe • Inverse Compton (X-ray) Emission flux : FIC ∝ ueuseedV energy index :aIC = aSR ueed=uCMB+usync+ugal+… uCMB : energy density of CMB 4.1 x 10 –13 (1 + z) 4 erg cm-3 ueand um Non-thermal radio and X-ray emissions in jets and lobes (e.g. Harris & Grindlay 1979, MNRAS 188, 25) • Synchrotron Radio Emission flux: FSR ∝ ueumV energy index : aSR in many cases….. useed~uCMB by comparing FSR and FIC

  5. “Jet” um~ (3.6 × 10-15)(G/10)2 ue~ (2.2 × 10-7)(10/G)2 (ue/um)~ 108 (10/G)4 (B ~0.3 mG) “arrowhead” um~ (4.2× 10-15)(G/10)2 ue~ (1.0 × 10-10)(10/G)2 (ue/um)~ 105 (10/G)4 (B ~ 0.3 mG) “diffuse” um~ (7.3 × 10-14) (B ~ 1.4 mG) ue~ (6.2 × 10-12) (ue/um)~ 100 (in average of the lobe) Centarusu B: structures and energy densities • Detected the diffuse X-ray emission and X-ray bright structures (“jet”, “arrowhead”) • Derived energy distributions in the “jet” & “arrowhead”, considering their expected bulk motions (d~0.94 (from radio luminosity ratio)), are…. The unit of energy densities are [ erg cm-3 ]

  6. Magnetic Field Energy umV [1058 erg] Lkin [(1+k) 1040 erg s-1] k: for positive particle Electron EnergyueV [1058 erg] LX(2-10keV) [1040 erg s-1] 2. Summary diagrams of IC-X-ray observation from radio lobes LkintAGE～ueV +umV ueV=umV ueV=10umV Isobe 2002 & his poster Lkin/(1+k) >LX(2-10keV) ueV > 10 umV

  7. ASCA image with overlaid VLA image (Kaneda et al. 1995, ApJ 543, L13; Ekers et al. 1983, A&A 127, 361 See also Feigelson et al. 1995, ApJ 448, L149) Brightness profile of radio (ueum) and X-rays (ue) FornaxA : ASCA 3. ASCA and Chandra observations of Fornax AA possible story of AGN (Tashiro et al. 2001, ApJ 546, L19)

  8. An X-ray “blob” 2 kpc from the galaxy radiates thermal X-rays Independent from jets or lobes “merging” is suggested (~ Gyrs. ago?) 2kpc 0.3-1.5keV (Chandra) 1.5-10keV (Chandra) HST: Grillmair et al., 1999, AJ 117, 167 X-ray “blob”(Kim & Fabbiano 2003, ApJ 586, 826) VLA Fomalont et al.ApJ 346, L17 1989)

  9. Two-temperature plasma emission kT = 0.45/ 0.37 keV Cooling Flow model kT= 0.19- 0.71 keV z = 0.07 X-ray spectrum from the “blob” X-ray 1.5-10keV • tcool= 1-7x107year

  10. Activity starts lobe size  before (t-106)yr “blob” tcool  after (t-107-8)yr Activity stops “lobe” tcool  after (t-109)yr No jet  before (t-105)yr speculation: Possible History of the nucleus activity (t-108)yr < AGN activity < (t-105) yr ? Since the total energy in the lobe ~ 1058 erg…., 1043 erg/s < Lkin < 1046 erg/s again, comparable with the AGN radiation ?

  11. Conclusions • With ASCA, Chandra and Newton, CMB boosted IC X-rays are observed from a number of radio lobes. • The derivedue tends to dominate um -- by an order of magnitude. • The electron energy, ueV, seems to be proportional to the nuclear luminosity, although the magnetic energy, umV does not dependent on it. • Centaurus B: particle energy ue dominates the magnetic field um, but it dissipates along the “jet”. • Fornax A: A possible AGN history is presented.

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