活動銀河のブラックホールと降着円盤 - Kagoshima Umilkyway.sci.kagoshima-u.ac.jp/~kameno/AGN_Radio/Chap03/...the Milky Way, which cannot be seen at optical wavelengths

電波望遠鏡で見る活動銀河京都大学宇宙物理教室集中講義 2009/06/10 - 12

活動銀河のブラックホールと降着円盤•BH存在の観測的証拠•BH連星探査•降着円盤•BHと降着円盤の撮像に向けて

電波望遠鏡で見る活動銀河京都大学宇宙物理教室集中講義 2009/06/10 - 12 Chap. 01

AGNの模式図エンジン

燃料

排気ガス

大規模/高効率なエネルギー発生機構

•ブラックホール•降着円盤の系と考えられる

質量降着率

母銀河の星間物質? or 星?

ジェット相対論的な速度のプラズマ流根元 : < 0.01 pcの細さ長さ：~ 106 pc

電波ローブプラズマの吹きだまり2


観測的なBH存在の証拠

3

r=20 pcでvrot=500 km s-1

→ M = 2.4 x 109 M

August 26, 2008 21:51 WSPC/INSTRUCTION FILE ms

9

4. Recent Overwhelming Evidence that Sgr A* is a SMBH

Evidence for the existence of SMBHs, especially for Sgr A*, has been steadily grow-ing over the years, but recently observational constraints have become so strongthat there can be almost no doubt that Sgr A* is a supermassive black hole.

4.1. Stars Orbiting an Immense Unseen Mass Concentration

Fig. 6. False color infrared image taken with by the European Southern Observatory’s Very LargeTelescope of the central few parsecs of the Milky Way. Superposed with a 100-times finer scaleis the orbital track of one star named S2. The orbital period of S2 is 15.8 years, and recentlya complete and closed elliptical orbit has been observed. The orbit requires an unseen mass of! 4 " 106 M! at the focal position, indicated by the arrow. The focal position is coincident withthe position of the compact radio source Sgr A* as discussed in §4.2. (Image courtesy R. Genzel.)

Continued monitoring of the positions of stars, with increasing positional accu-racy, led to clear detections of acceleration (ie, curving motions on the sky)35,36.Importantly, the directions of the acceleration vectors “pointed” to a common cen-tral gravitational source very close to the position of Sgr A*. Recently these obser-vations culminated in the discovery that stars are executing elliptical paths (orbits)on the sky 35,37,38,39,40. One star named S2 (a.k.a. S0-2) and has now been ob-served over one complete 15.8-year elliptical orbit (see Fig. 6). All stellar orbits arewell fit by a single enclosed mass and focal position (see Fig. 7). Two stars have

M 87Sgr A*

August 26, 2008 21:51 WSPC/INSTRUCTION FILE ms

8 Mark J. Reid

Milky Way26,27,28,29,30. There is indeed a dense cluster of stars at the center ofthe Milky Way, which cannot be seen at optical wavelengths because visible light istotally absorbed by dust between the Galactic center and the Sun. However, thesestars can be seen at infrared wavelengths, where ! 10% of the 2 µm wavelengthlight is received. Using novel techniques that allow di!raction-limited imaging in theinfrared, groups led by Reinhard Genzel in Germany and Andrea Ghez in the USAhave been measuring positions of these stars for more than a decade 31,32,33,34.These results showed that stars projected very close to the position of Sgr A* weremoving very rapidly across the sky.

Fig. 5 plots the stellar velocity dispersions available in 1998 and the inferredenclosed mass as a function of projected distance from the position of Sgr A*.Measurements of stellar radial velocity sample projected distances from 4 to 0.1parsecs and proper motions (motions on the plane of the sky) sample from 0.3 to0.01 parsecs. Between projected radii of 0.2 and 0.01 parsecs, the velocity dispersion,!, increases as ! " 1/

#r. The enclosed mass estimated for virialized material is

indeed nearly constant between these radii, greatly strengthening the case for alarge “point mass.” The implied mass density, while very high (comparable to thatinferred from the water masers in the galaxy NGC 4258 discussed in §2), still couldnot rule some alternatives to a SMBH (see §5).

Fig. 5. Measured stellar velocity dispersions (left panel) and inferred enclosed mass (right panel)versus projected distance from the Galactic center (after Eckart & Genzel 1997 and Ghez etal 1998). The line through the data corresponds to Keplerian orbits for a point-like mass of2.5! 106 M! and fits the data well for radii smaller than 0.2 pc. Beyond this radius, the velocitydispersions exceed that expected from a point mass, owing to the contribution to the enclosedmass from an observed dense cluster of stars.

Eckert & Genzel 1997; Ghez+1998;Reid 2008

r < 0.2 pcでM(r) = 2.5x106 M

S2星の軌道運動 → 4x106 M


Sgr A*の質量とサイズ

4©!!""#!Nature Publishing Group!

!

A size of ,1 AU for the radio source Sgr A* at thecentre of the Milky WayZhi-Qiang Shen1, K. Y. Lo2, M.-C. Liang3, Paul T. P. Ho4,5 & J.-H. Zhao4

Although it is widely accepted that most galaxies have super-massive black holes at their centres1–3, concrete proof has provedelusive. Sagittarius A* (Sgr A*)4, an extremely compact radiosource at the centre of our Galaxy, is the best candidate forproof5–7, because it is the closest. Previous very-long-baselineinterferometry observations (at 7mm wavelength) reported thatSgr A* is,2 astronomical units (AU) in size8, but this is still largerthan the ‘shadow’ (a remarkably dim inner region encircled by abright ring) that should arise from general relativistic effects nearthe event horizon of the black hole9. Moreover, the measured sizeis wavelength dependent10. Here we report a radio image of Sgr A*at a wavelength of 3.5mm, demonstrating that its size is ,1 AU.When combined with the lower limit on its mass11, the lower limiton the mass density is 6.5 3 1021M( pc23 (whereM( is the solarmass), which provides strong evidence that Sgr A* is a super-massive black hole. The power-law relationship between wave-length and intrinsic size (size / wavelength1.09) explicitly rulesout explanations other than those emission models with stratifiedstructure, which predict a smaller emitting region observed at ashorter radio wavelength.

Past very-long-baseline interferometry (VLBI) observations12–16 ofSgr A* have revealed an east–west elongated structure whoseapparent angular size at longer wavelengths is dominated by theinterstellar scattering angle, that is, Vobs !V1cm

obs l2, where Vobs is the

observed size in milliarcseconds (mas) at wavelength l in cm, andequals V1cm

obs at 1 cm. Thus, VLBI observations at shorter millimetrewavelengths, where the intrinsic structure of Sgr A* could becomecomparable to the pure scattering size, are expected to showdeviations of the observed size from the scattering law. This hasbeen demonstrated by the recent detection of the intrinsic size at7mm (ref. 8). On 20 November 2002, we successfully carried out anobservation of Sgr A* with the Very Long Baseline Array (VLBA) atits shortest wavelength of 3.5mm (ref. 10). Our observation, withthe steadily improved performance of the VLBA system, hasproduced the first (to our knowledge) high-resolution image ofSgr A*made at 3.5mm (Fig. 1), which exhibits an elongated structuretoo.To yield a quantitative description of the observed structure,

we tried a model fitting procedure17 in which the amplitudeclosure relation is applied. Compared to the conventional VLBI

LETTERS

Figure 1 |High-resolutionVLBI image of SgrA* at 3.5mmobtainedwith theVLBA on 20 November 2002. The observations were flexibly scheduled toensure good weather conditions at most sites, and the data were recorded atthe highest possible recording rate of 512Mbit s21. Standard visibilityamplitude calibration including the elevation-dependent opacity correctionwas done, and the final image was obtained after several iterations of the self-calibration and cleaning procedures. The calibrated total flux density is

about 1.2 Jy. a, A uniformly weighted image with the restoring beam(indicated at the lower left corner) of 1.13mas £ 0.32mas at 98. The peakflux density is 1.08 Jy beam21. Contour levels are drawn at 3j £ (21, 1, 2, 4,8, 16, 32); 3j ! 17.5mJy beam21. b, A super-resolution image with acircular beam of 0.20mas from which an east–west elongated structure canbe seen (see Table 1). Note the different scales. The contour levels are thesame as that in awith the corresponding peak flux density of 1.01 Jy beam21.

1Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai 200030, China. 2National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, Virginia 22903,USA. 3Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA. 4Harvard-Smithsonian CfA, 60 Garden Street,Cambridge, Massachusetts 02138, USA. 5Institute of Astronomy & Astrophysics, Academia Sinica, PO Box 23-141, Taipei 106, Taiwan, China.

Vol 438|3 November 2005|doi:10.1038/nature04205

62

VLBA@86 GHz 超分解→電波放射領域 ~ 1 AU

©!!""#!Nature Publishing Group!

!

A size of ,1 AU for the radio source Sgr A* at thecentre of the Milky WayZhi-Qiang Shen1, K. Y. Lo2, M.-C. Liang3, Paul T. P. Ho4,5 & J.-H. Zhao4

Although it is widely accepted that most galaxies have super-massive black holes at their centres1–3, concrete proof has provedelusive. Sagittarius A* (Sgr A*)4, an extremely compact radiosource at the centre of our Galaxy, is the best candidate forproof5–7, because it is the closest. Previous very-long-baselineinterferometry observations (at 7mm wavelength) reported thatSgr A* is,2 astronomical units (AU) in size8, but this is still largerthan the ‘shadow’ (a remarkably dim inner region encircled by abright ring) that should arise from general relativistic effects nearthe event horizon of the black hole9. Moreover, the measured sizeis wavelength dependent10. Here we report a radio image of Sgr A*at a wavelength of 3.5mm, demonstrating that its size is ,1 AU.When combined with the lower limit on its mass11, the lower limiton the mass density is 6.5 3 1021M( pc23 (whereM( is the solarmass), which provides strong evidence that Sgr A* is a super-massive black hole. The power-law relationship between wave-length and intrinsic size (size / wavelength1.09) explicitly rulesout explanations other than those emission models with stratifiedstructure, which predict a smaller emitting region observed at ashorter radio wavelength.

Past very-long-baseline interferometry (VLBI) observations12–16 ofSgr A* have revealed an east–west elongated structure whoseapparent angular size at longer wavelengths is dominated by theinterstellar scattering angle, that is, Vobs !V1cm

obs l2, where Vobs is the

observed size in milliarcseconds (mas) at wavelength l in cm, andequals V1cm

obs at 1 cm. Thus, VLBI observations at shorter millimetrewavelengths, where the intrinsic structure of Sgr A* could becomecomparable to the pure scattering size, are expected to showdeviations of the observed size from the scattering law. This hasbeen demonstrated by the recent detection of the intrinsic size at7mm (ref. 8). On 20 November 2002, we successfully carried out anobservation of Sgr A* with the Very Long Baseline Array (VLBA) atits shortest wavelength of 3.5mm (ref. 10). Our observation, withthe steadily improved performance of the VLBA system, hasproduced the first (to our knowledge) high-resolution image ofSgr A*made at 3.5mm (Fig. 1), which exhibits an elongated structuretoo.To yield a quantitative description of the observed structure,

we tried a model fitting procedure17 in which the amplitudeclosure relation is applied. Compared to the conventional VLBI

LETTERS

Figure 1 |High-resolutionVLBI image of SgrA* at 3.5mmobtainedwith theVLBA on 20 November 2002. The observations were flexibly scheduled toensure good weather conditions at most sites, and the data were recorded atthe highest possible recording rate of 512Mbit s21. Standard visibilityamplitude calibration including the elevation-dependent opacity correctionwas done, and the final image was obtained after several iterations of the self-calibration and cleaning procedures. The calibrated total flux density is

about 1.2 Jy. a, A uniformly weighted image with the restoring beam(indicated at the lower left corner) of 1.13mas £ 0.32mas at 98. The peakflux density is 1.08 Jy beam21. Contour levels are drawn at 3j £ (21, 1, 2, 4,8, 16, 32); 3j ! 17.5mJy beam21. b, A super-resolution image with acircular beam of 0.20mas from which an east–west elongated structure canbe seen (see Table 1). Note the different scales. The contour levels are thesame as that in awith the corresponding peak flux density of 1.01 Jy beam21.

1Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai 200030, China. 2National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, Virginia 22903,USA. 3Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA. 4Harvard-Smithsonian CfA, 60 Garden Street,Cambridge, Massachusetts 02138, USA. 5Institute of Astronomy & Astrophysics, Academia Sinica, PO Box 23-141, Taipei 106, Taiwan, China.

Vol 438|3 November 2005|doi:10.1038/nature04205

62

4x106 Mとすると12.6 Rs

密度：6.5x1021 M pc-3


NGC 4258のケース:高速度メーザーの発見

5

低光度活動銀河NGC 4258中心からのH2Oメーザー放射 (22.235 GHz)野辺山45m電波望遠鏡で±1000 km s-1の速度成分を発見 (Nakai et al. 1993)

※当初はジェット運動を疑っていた



5





5




NGC 4258 : 加速度の検出

6

視線速度の変化系統速度成分：加速度あり

v = 9.6± 1.0 km s!1yr!1

高速度成分：有意な速度変化なし(Haschek+1993, Greenhill+1994, Nakai+1995)


NGC 4258 : ケプラー回転円盤の発見

7

1500 13001400

1

2

3

4

0

Flu

x D

en

sity (

Jy)

550 450 -350 -450

0.1 pc

2.9 mas

Line-of-Sight Velocity (km s )-1

10 5 0 -5 -10Impact Parameter (mas)

-1000

0

1000

2000

LO

S V

elo

city (

km

/s)

Proc. Natl. Acad. Sci. USA 92 (1995) 11431

cn

E OIL-i ;lliuiiiiie.itll++ IlII ''

OZ' ~ 1 '~

01:-0.2.

L

-0.4

I ;,i1:

I'llJ,

-.3 -0. .1 0. 0

-0.3 .0.2 -0. 0.0Distance along major axis, mas

C,, I, ,1 |

1.1 0.2

0 10'~

O.5-

E ~~~~~I

-0.05 0.00 0.05 0.10 0.15Distance along major axis, mas

FIG. 5. ..Estimated height of systemic maser features above or belowthe plane of the disk in 1994. Thickness of the disk is unresolved bythese observations. Errors bars represent lo- uncertainties in positionestimates.

where MD is the mass of the disk interior to R. For a moleculardensity of 1010 cm-3 (the maximum allowed to avoid quench-ing the maser action), p = 3.2 x 10-14 gcm-3 and I = 56g'cm-2, we obtain Q = 6 at the inner edge of the disk and Q= 1 at the outer edge. Hence, the disk appears to be onlymarginally stable, especially at its outer edge. Perhaps thisexplains the absence of maser emission beyond the observedouter radius. The disk stability is discussed further by Maoz (23),who suggests that the regular spacing among the high velocitymaser features may indicate the presence of spiral structure.We can estimate the accretion rate from our data (see also

ref. 24). From the continuity equation the accretion rate is

M= 27rRIVR, [13]

where VR is the radial infall drift velocity. The observationallimit on the radial velocity is VR : 10 kms-1 (based on acomparison of optical and radio systemic velocities). This givesa limit on the mass accretion rate of about 1 M®-yr- 1. From thetheory of a stable thin disk (21), vR = av,,(H/R)2, where a isthe viscosity parameter. For a = 0.1, HIR < 0.0025 we obtainvR < 0.0007 kms 1-, and M = 7 x 10-5 Mo,yr-1. Note that thecharacteristic lifetime of the disk, MDIM = R3 (2H2v,a) = 108yr. This is a lower limit. If we take this value as the massaccretion rate and convert it to luminosity with an efficiencyof 10%, of which 10% appears as x-ray emission, then it couldpower an x-ray source of 5 x 1040 erg s-1. The observed x-rayluminosity is 4 x 1040 erg s-1 (25).

A Massive Black Hole?

The high enclosed mass that is inferred from the Keplerianrotation curve (Fig. 2) and the exceptionally small inner radius

of the region populated by masers imply a central mass density>4 x 109 M,,pc-3. The greatest known densities for galacticglobular clusters are 105 M,, pc-3. Whatever binds the mas-ing disk has a very high mass density by the standards of stellarclusters (actually only 3 x 10-3g.cm-3). The small deviationsof the maser features from a Keplerian curve, :3 kms- 1, limitthe number of cluster members that could lie between theinner and outer radii of the masing disk. Maoz (26) adopted aPlummer cluster density model to show that >99% of thecluster mass must lie within the inner radius. Furthermore,within the core radius, the mass density would be -4.5 x 1012Mo.pc-3. He calculated that if the cluster consisted mainly ofstars of mass >0.03 M0D, then it would evaporate on a time scaleshort with respect to the age of the galaxy. On the other hand,if it consisted mainly of objects with mass <0.03 Me, then thecluster would be disrupted by physical collisions on a similiarlyshort time scale. Hence, the high precision of the Keplerianrotation curve of the high-velocity maser features stronglysuggests that the central mass is not a stellar cluster, but rathera supermassive black hole.The case for massive black holes in other galaxies, including

our own, is reviewed by Kormendy and Richstone (27). Thelimit on the mass density for the object in NGC4258 is muchgreater than any of the other massive black hole candidates,

Vrot - 770 km/s

beISo, .

Radio ContinuumSource

\ R-0.13pc

-Vb&iaj

Vrot - 1080IIt

A'l

km/s \

I*

0~~~~~~~~E00~~~~~~0

J-c

Vgalaxy+Vroi A. Vgalaxy-VrotVgaiaxy

QW

oCD0)c

0

705-)

0L0

Observed maser spectrum

FIG. 6. Cartoon of the maser geometry for a nearly edge-on disk.The view is from slightly above the plane containing the disk and theEarth. The masing region occupies an annulus, with a fractional radialthickness of 0.5, that probably lies within a more extensive dusty torus.Masers in the systemic-velocity group become visible to us when theypass in front of the continuum source, which they amplify, and whosediameter may be inferred from the angular extent of the maserfeatures. However, the high-velocity features do not amplify a back-ground source, relying instead on long velocity-coherent gain pathsthrough the disk. The emission that we see is beamed anisotropically.However, the disk structure is apparent, presumably, to all observersfor whom it is nearly edge-on. Vrot, disk rotation velocity; Vgalcy, galaxyvelocity.

L:

Colloquium Paper: Moran et al.

I.

Iccc

'ic

c

Miyoshi+1995; Herrnstern+1999


大質量BHの形成プロセス

8

1pc

0.01pc

合体による成長?質量降着による成長?

T ! M

m

! = 0.057, m = 1.2 M! yr"1, M = 108 M!

T ! 108 yrとすると → 妥当

成長のタイムスケール・角運動量の抜き取り = 力学的摩擦が必要

星団 + BH・中間質量BHの発見

e.g. Makino, PTPh Suppl, 155, 190

Matsushita+2000; Matsumoto+2001

・連星BHの探査


2つの中心核

9

3C 757 kpc separation

VLA image of 3C 75 at 6 cm (Owen et al. 1985)

0402+379

VLBA image at 2 cm (Rodriguez et al. 2006)

7 pc separation


連星BHの探査と軌道

10

ジェットの蛇行 : 歳差運動？– 1928＋738（Roos et al. 1993）

遠方（z=0.3）のクエーサー3C66Aに対する、近傍（z=0.02）の電波銀河3C66Bのコア位置 - 周期1.05年のコア位置変動 (Sudou+2003)


連星BHの探査と軌道

10

ジェットの蛇行 : 歳差運動？– 1928＋738（Roos et al. 1993）

遠方（z=0.3）のクエーサー3C66Aに対する、近傍（z=0.02）の電波銀河3C66Bのコア位置 - 周期1.05年のコア位置変動 (Sudou+2003)


連星BH候補天体

11

天体 M[M] r[pc] P[yr] Red-shift Ref.

3C345 1.5×109 0.64 170 0.595 1

1978+738 108 0.003 2.9 0.3 2

OJ287 5×109 0.1 9 0.306 3

NGC6251 108 0.03 50 0.025 4

3C390.3 7×109 0.3 300 0.056 5

3C66B <5×1010 <0.01 1.05 0.0215 6

1: Lobanov & Roland 2002, 2: Roos et al. 1993, 3: Sillanpaa et al. 1988,

4: Jones et al. 1986, 5: Gaskell 1996, 6: Sudou et al. 2003

まとめ：須藤広志@岐阜大


降着円盤とは

12

•連星系（μクェーサー, X線連星, 矮新星, etc.)•Tタウリ型星•活動銀河核


降着円盤のエネルギー源

13

U : 重力ポテンシャル K : 運動エネルギー

ビリアル定理

KU

KU L

Loss

2K + U = 0

エネルギー収支 U + K + L = 0

L = K = !12U

L : 損失放射, 移流, ジェット加速…

r : 半径

エネルギー

降着


降着円盤のエネルギー源

13

U : 重力ポテンシャル K : 運動エネルギー

ビリアル定理

KU

KU L

Loss

2K + U = 0

エネルギー収支 U + K + L = 0

L = K = !12U

L : 損失放射, 移流, ジェット加速…

r : 半径

エネルギー

降着


角運動量輸送

14

角運動量保存則 → 損失がないと落ちない (e.g. 太陽系の惑星）

粘性による角運動量の輸送

・トルク∝角速度の差 Tr! = !!rd"

dr

T:トルクν : 粘性Σ : 面密度r : 半径ω : 角速度

・内側→外側へ角運動量を輸送

内側はますます降着！

粘性の起源は何？

•分子粘性…効かない•乱流粘性？•放射粘性？•磁気乱流粘性？

! = "csH


角運動量輸送

14

角運動量保存則 → 損失がないと落ちない (e.g. 太陽系の惑星）

粘性による角運動量の輸送

・トルク∝角速度の差 Tr! = !!rd"

dr

T:トルクν : 粘性Σ : 面密度r : 半径ω : 角速度

・内側→外側へ角運動量を輸送

内側はますます降着！

粘性の起源は何？

•分子粘性…効かない•乱流粘性？•放射粘性？•磁気乱流粘性？

! = "csH


降着円盤のモデル

15

スリム円盤

標準円盤

ADAF/RIAF（移流優勢円盤）

(Abramowicz et al. 1988)

(Shakura & Sunyaev 1973)

(Narayan & Yi 1994)

(Kato, Mineshige, Fukue 1998)

･ Te ~ 106 K

･ Narrow-Line Sy1

m = M/! > 1

･ Te ~ 105 K

･ Quasars

m = M/! ! 1

･ Te ~ 109-10 K

･ Low-luminosity AGNs

m = M/! ! 1


降着円盤のSED

16

–33

–

Fig.

8.—Interp

olatedSE

Ds

ofall

the

objects

(solidlin

es)norm

alizedto

the

1keV

lum

inosity

of

M81.

The

med

ianrad

io-loud

(dottedlin

e)an

drad

io-quiet

(dashedlin

e)SE

Ds

ofE

lviset

al.(1994),

norm

alizedsim

ilarly,are

overplotted

forcom

parison

.

Ho 1999, ApJ 516, 672

さまざまなAGNのSpectral Energy Distribution (コンポジット)


降着円盤のSED

16

–33

–

Fig.

8.—Interp

olatedSE

Ds

ofall

the

objects

(solidlin

es)norm

alizedto

the

1keV

lum

inosity

of

M81.

The

med

ianrad

io-loud

(dottedlin

e)an

drad

io-quiet

(dashedlin

e)SE

Ds

ofE

lviset

al.(1994),

norm

alizedsim

ilarly,are

overplotted

forcom

parison

.

Ho 1999, ApJ 516, 672


Synchrotron + Inverse ComptonADAF/RIAF円盤成分

Tion ! Tvirial !mpc2

kBr= 1013(r/rg)!1[K]

Te !mec2

kBr= 6" 109(r/rg)!1[K]


降着円盤のSED

16

–33

–

Fig.

8.—Interp

olatedSE

Ds

ofall

the

objects

(solidlin

es)norm

alizedto

the

1keV

lum

inosity

of

M81.

The

med

ianrad

io-loud

(dottedlin

e)an

drad

io-quiet

(dashedlin

e)SE

Ds

ofE

lviset

al.(1994),

norm

alizedsim

ilarly,are

overplotted

forcom

parison

.

Ho 1999, ApJ 516, 672




kBr= 1013(r/rg)!1[K]

Te !mec2

kBr= 6" 109(r/rg)!1[K]

big blue bump標準円盤成分

Te! ! 6.8" 105!!1/4

!L

Ledd

"1/2

!!1/4

!L

1039W

"!1/4

(r/rg)!3/4[K]


降着円盤のSED

16

–33

–

Fig.

8.—Interp

olatedSE

Ds

ofall

the

objects

(solidlin

es)norm

alizedto

the

1keV

lum

inosity

of

M81.

The

med

ianrad

io-loud

(dottedlin

e)an

drad

io-quiet

(dashedlin

e)SE

Ds

ofE

lviset

al.(1994),

norm

alizedsim

ilarly,are

overplotted

forcom

parison

.

Ho 1999, ApJ 516, 672


dust成分



kBr= 1013(r/rg)!1[K]

Te !mec2

kBr= 6" 109(r/rg)!1[K]

big blue bump標準円盤成分

Te! ! 6.8" 105!!1/4

!L

Ledd

"1/2

!!1/4

!L

1039W

"!1/4

(r/rg)!3/4[K]


降着円盤/BHの撮像可能性

17

VSOP-2 band

VSOP

VSOP-2

log[radius, Rs]

log[T

em

pera

ture

, K

]

Sgr A*のSED (Manmoto+97) にVSOP-2の感度・分解能を加筆

Takahashi+04 : Black Hole Shadowのimage simulation

VSOP-2によって降着円盤は撮像できそうBHシルエットはchallenging


降着円盤撮像のサイエンス

18

降着円盤の粘性…磁気乱流起源？

MHDシミュレーション結果Machida, Hayashi, & Matsumoto (2000), ApJ 532, L67

降着円盤内の磁場構造をマッピングで検証 ↑ VSOP-2による偏波観測

乱流構造の反転タイムスケール : 11 hr for Sgr A*280 days for M 87

円盤内の磁場方向が乱流状に変化・磁気リコネクション時にフレア

! ! "B!Br#4"P0 ! = "csH

Documents

活動銀河の ブラックホールと降着円盤 - Kagoshima Umilkyway.sci.kagoshima-u.ac.jp/~kameno/AGN_Radio/Chap03/...the Milky Way, which cannot be seen at optical wavelengths

活動銀河のブラックホールと降着円盤 - Kagoshima Umilkyway.sci.kagoshima-u.ac.jp/~kameno/AGN_Radio/Chap03/...the Milky Way, which cannot be seen at optical wavelengths