AGN降着流のX線観測 1. 2. 3. 4. AGNからのX線降着円盤からのX線(GBH) AGNのX線観測実例 VSOP-2に向けて幅良統 (名古屋大学) X-rays from AGNs 0.01 10!3 10!4 10!5 keV (Photons cm!2 s!1 keV!1) 0.1 Power law Absorbed power law Thermal emission Compton reﬂection Thomson scattering 0.2 0.5 1 2 Energy (keV) 5 10 Accretion Disk in AGNs • Big Blue Bumpの存在 • • 標準円盤：内縁温度が極端紫外部 soft X-ray excessの存在 • 標準円盤にしては熱すぎる (0.1-0.2 keV) • hot accretion disk ? → 一つの解釈ではある降着流の理解は不十分 X-rays from Accretion Disks • 恒星質量ブラックホールの観測 • high/soft ⇆ low/hard 状態遷移 • very high state、slim disk state • 降着円盤３つのブランチ X-ray spectra of GBH very high state low/hard state high/soft state 例: RXTEJ1550-564 RXTE PCA+HEXTE Done astro-ph/0203246 Very High State steepなpower law的 photon index 2.4-3 L/Ledd > 0.2?であらわれる High/Soft 強いsoft成分 +弱いhard成分 Low/Hard power lawが卓越 photon index 1.7 L/LEdd < 2-3%であらわれる State of the Accretion Disk Luminosity 大 Slim Disk state Very High state High/Soft state (Intermediate state) Low/Hard state Quiescent state Luminosity 小降着円盤 Slim Disk Standard Disk Radiatively-Ineﬃcient Flow (ADAF etc.) Properties of Different A.D. states very high high/soft blackbody soft comp. + spectrum + power power law law other prop. QPO L ∝ T4 low/hard power law radio jet Low Luminosity AGNs ・・・・・・ LLAGNは多い(近傍の明るい銀河の>1/3) そのうちの2/3はLINER 光度が小さい(Eddington 光度の1%以下) 放射効率が悪い(通常のAGNより1-4桁下) Big blue bump (BBB)がない Radio loud Terashima & Wilson 2003 Low Luminosity AGNs NGC 3998 Power lawモデル Γ = 1.87(1.85-1.88) NH = 3.3x1020 cm-2 LX = 5.9x1041 ergs/s Fe K (6.4 keV, narrow) EW < 25 eV (Δχ2=2.7) Optically thick な物質が無い光学的に薄い (RIAF的な)降着円盤？ Ptak et al. 2004 Narrow-Line Seyfert 1s •Sub-class of type 1 Seyfert galaxies •Relatively narrow (< 2000 km/s) Balmer line Broad-Line Seyfert 1 Galaxies (BLS1s) •Large amplitude & short time variability •relatively small black hole ? •Similar luminosity to BLS1s •strong soft excess •high-mass accretion rate? Rapid growth BH? Early phase of AGN evolution? QPO in NLS1 RE J1034+396からQPO検出・Narrow-line Seyfert 1 ・Strong soft excess + pl QPO → MBH ∼ 4 x 105 Msolar → Lbol ∼ 10 x LEdd Gierlinski et al. 2008, Nature 455, 369 Slim disk state ? A. D. states v.s. AGN type very high high/soft blackbody soft comp. + spectrum + power power law law other prop. AGNs QPO L ∝ T4 NLS1? & Sey1? low/hard power law radio jet LLAGN? GBHとのアナロジーからAGN typeと降着円盤の状態は対応がつきそう・・・ GBHとの決定的な違い → 単一objectのstate change 極端な強度／スペクトル変動を示す天体の観測 X-ray study of NGC 4051 UV (2910Å) image of NGC 4051 • Nearby (z=0.0023) NLS1 • BH mass • One of the lowest luminosity object (∼ 1041 erg s-1) • Strong intensity and spectral variation on timescales of hours to years 106 Msolar 2001 Dim 1 Flare 2002 20 60 60 Light Curve Dim 3 10 5 [counts sec!1] 40 0 20 [counts sec!1] 20 2×104 Time [sec] 4×104 0 0 0 [counts sec!1] 40 15 Dim 2 0 • • 5×104 Time [sec] 105 0 5×104 Time [sec] 2001 • • High ﬂux state Large amplitude & short time variability 2002 • • Low ﬂux state Small amplitude variability 105 Variability Amplitude ● 2001 □ 2002 <X>; average count rate S; total variance σ; statistical error Dim1 • Total light curves are divided into 5 ksec duration • Calculate Fvar in each segment • Most data points are distributed 0.1 0.4 • Fvar = 0 in the Dim3 state Dim2 Dim3 Dim3 is stable state Flare Counts-counts Plot correlation between soft (0.3-0.5 keV) and hard (4.0-12.0 keV) band count rate Flare 2001 2002 Dim1 Positive correlation Dim2 Dim3 Large deviation in Dim3 state Spectra in Various States Flare Dim 1 Dim 2 Dim 3 100 counts s!1 keV!1 10 1 0.1 0.01 0.5 1 2 Energy [keV] 5 10 Differential Spectrum 100 counts s!1 keV!1 10 Flare - dim1 1 0.1 0.01 10!3 ! soft comp. + power law 連続成分が単調に増加 4 2 0 !2 !4 0.5 1 2 Energy [keV] 5 10 Spectrum in Dim1 State counts s!1 keV!1 10 ! 吸収を受けたpower law 反射成分鉄輝線 stable成分普遍的に存在 1 0.1 0.01 4 2 0 !2 !4 0.5 1 2 Energy [keV] 5 10 Differential Spectrum Heavily absorbed component NH 1023 cm-2 counts s!1 keV!1 1 0.01 ! Dim2 − Dim3 Absorption may play an important role in the spectral variation 0.1 4 2 0 !2 !4 0.5 1 2 Energy [keV] 5 10 Spectrum in Dim3 State Thermal emission from optically thin plasma extended regionからの emissionが支配的 0.01 10!3 10!4 吸収成分無し FX [keV(photons cm!2 s!1 keV!1)] Compton reﬂection from distant matter This is consistent with Fvar = 0 in Dim3 state 0.5 1 2 Energy [keV] 5 10 Spectral Variation •Dim3 ⇔ Dim2; Change of the absorbed component •Can the spectral variation be recognized as the variation 0.8 of the absorbed component ? 0.4 0.2 0 Fcover [10!11 erg cm!2 s!1] 0.6 □ 2001 ● 2002 0 1 2 F2!10 [10!11 erg cm!2 s!1] 3 2001; almost constant absorbed ﬂux 2002; gradually decrease with total ﬂux Summary of Results Flux State Fvar C-C plot Spectrum Absorber Max Flare 0.1 0.4 Positive constant Dim1 Pl + Ab Dim2 < 0.1 Min Dim3 =0 Deviation decrease Thermal + Comp disappear 10 1 2 Energy (keV) 5 0.1 0.01 10!3 10!4 1 2 Energy (keV) 10 0.01 10!3 10 0.2 0.5 1 2 Energy (keV) 5 10 10 !4 10 !3 0.01 Dim3 10 !5 keV (Photons cm!2 s!1 keV!1) 5 Dim2 0.1 0.5 0.5 10!4 10 !4 10 !3 0.01 Dim1 0.2 0.1 10 !5 keV (Photons cm!2 s!1 keV!1) 0.2 •Assumption •Fdir ∝ Semi •Semi > Sabs •Fabs = const. •Semi < Sabs •Fabs ∝ Semi •Semi = 0 •Fabs = 0 5 10!5 1 2 Energy (keV) keV (Photons cm!2 s!1 keV!1) 0.5 0.1 0.2 10!5 10!4 10!3 0.01 keV (Photons cm!2 s!1 keV!1) Flare 10!5 keV (Photons cm!2 s!1 keV!1) 0.1 Interpretation 0.2 0.5 1 2 Energy (keV) 5 Dim3 spectrum consists of stable components No variavility found 10 NGC 4051のまとめ大きなﬂux 変化に伴うスペクトル変化 dim state → 変動無し LLAGN的特徴 radiatively eﬃcient → ineﬃcient ? LLAGNはradio loud dim stateではradio ﬂux増加？ radio ﬂuxの変動探査が本質的候補天体 X線領域で極端なlow flux stateになる天体 D [Mpc] log Msolar F [mJy] NGC 4051 12 6.2 10 Mrk 335 100 7.1 3 Mrk 766 50 6.5 15 NGC 3516 38 7.6 2 NGC 2992 30 7.7 91 NGC 2992 RXTE, MAXI等モニタ観測 → dim state確認明らかになると嬉しい事 normal stateとdim stateの電波強度比較電波強度(jet origin)とディスク状態の関係 AGNにおけるstate changeの実態 state changeのtriggerは？理論的予測＋電波観測＋X線観測が重要