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Diagnostics of thermal plasma with eV-level

ResolutionManabu ISHIDA

Tokyo Metropolitan University

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Objectives of Plasma Diagnostic (with NeXT in particular)

Measurements of physical parameters of thermal plasma. kT ~ keV For better understanding of star-forming region, star, planetary nebula, supernova remnant, binary, galaxy, cluster of galaxies…

He(H)-like K of iron in general, of other metals from diffuse source which are inaccessible with Chandra/XMM-Newton.

Te Tioni TZ AZ ne etc…■ Bulk motion of plasma in particle-acceleration regions. Geometry of the plasma surrounding a compact object. Turbulence in the clusters of galaxies Shock front of SNR.Help understanding non-thermal universe in E > 10 keV.

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Iron spectrum at Tmax of He-like K

• He-like• resonance (r)

w : 1P1 → 1S0

• intercombination (i) x : 3P2 → 1S0 y : 3P1 → 1S0

• forbidden (f) z : 3S1 → 1S0

• H-like• resonance

Ly1 : 2P1/2 → 2S1/2 Ly2 : 2P3/2 → 2S1/2

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Density diagnostics with He-like triplet

• 3S1 decays through 3P2,1 if A(3S1-1S0) ~ neC(3S1-3P2,1)• f + i = const. • Caution: 3S1 →3P2,1 occurs also with UV photo-excitation.• Resolving degeneracy between ne and V in a point source.

Porquet et al (2001)

Ishida (1995)

ri

f

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He-like triplet as a density probe

nc(Z) = 6.75 (Z-1)11.44 cm-3

Tm(Z) = 8320 (Z-0.4)2.71 K

CVs

T Tau star

Proto starStellar flareSolar corona

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Density measurement of AE Aqr with XMM RGS

• AE Aqr (mCV, Pspin = 33.08s, Porb = 9.88h, B = 105-6G ?)

• ne~1011cm-3, p = (2-3)x1010cm

Itoh et al. (2006)

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What’s happening in AE Aqr ?!• In the accretion column of mCV

ne~1016cm-3, p ~107cm, whereas

ne~1011cm-3, p = (2-3)x1010cm. kT (~ GMmH/R) of AE Aqr is extremely lower than other mCVs, suggestive of intermediate release of the gravitational energy.

Plasma is surely accreting because we have X-ray emission, but not arriving at the white dwarf surface, diffuse in an orbit scale.

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AE Aqr as a Magnetic Propeller Source

• Steady spin down (P-dot = 5.64x10-14 s s-1) for >14 yrs.

• TeV -ray emission.• Note: no bulk velocity is detected from oxygen K.

v < 300 km s-1 (expected ~100km s-1).• The maximum vbulk is expected iron K.

Theme of the calorimeter onboard NeXT.

Wynn & King (1997)Wynn & King (1997)

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Origin of the GRXE• Thin thermal: kTmax ~ 7keV.• Diffuse ?

Ebisawa et al. (2005)

• Ensemble of point sources ? Revnivtsev et al. (2006) CVs or Active Star Binaries.

• Suzaku clearly detected 6.4keV line from the GRXE.ASB CV

• Suzaku should measure spatial uniformity of intensity ratios of the iron K components.

• Debate will be terminated if ne is measured with the NeXT calorimeter.

Suzaku XIS 6.4keV

Thanks to S. Yamauchi@IwateThanks to S. Yamauchi@Iwate

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He-like Satellite lines• Satellite lines: a series

of mission lines at energies slightly lower than w.

• More intense for larger Z, prominent for iron.

New information that can be accessed first by the NeXT calorimeter.

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Origin of the Satellite Lines• Satellite lines of Z+z

originates from ion Z+(z1).• Spectator shields part of

the charge of the nuclei.Er > ES4 > ES3 > ES2

• ES2 is strongest and most separated from w.

• Sn (n≧4) cannot be separated from r.

• Satellite of H-like K originates from DR.

• Satellite of He-like K 1s2[sp]2p→(1s)22p: DR 1s2[sp]2s→(1s)22s : DR+IE

DR: interaction of e- with He-like ion.

IE: additionally with Li-like ion.

0 E

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Spectrum of H-like/He-like iron K

◆Number of major satellite lines with spectator n=2 is 22. Spectator = 2p (DR): a, b, c, …, m, n: 14 in total.

j and k are prominent Spectator = 2s (DR+IE): o, p, q, …, u, v: 8 in total.

r, q, and t are strong in ionizing plasma

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Te with G = (x+y+z)/w vs j+k/w

w, j, k: all originate from interaction between an electron and a He-like ion. Their intensity ratio is a function only of Te. It does not matter even if NEI. The intensity ratio does not depend on ne. It has been claimed that G = (x+y+z)/w is a good measure of Te, however …. j+k/w is much more sensitive to Te.

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Intensity of the satellites with Te

kTe = 1.6keV

kTe = 3.2keV

kTe = 7.9keV

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SNR: NEI with kTe = 2keV

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Te from j/w, Tioni from (q+t)/w

• For SNR: j/w: Te, (q+t)/w: net, line width: TZ, central energy: vbulk.

• For recombining plasma j/w is stronger, (q+t)/w is weaker than that of CIE plasma. Central region of the cluster of galaxies, stellar flare,

post-shock accregion flow in mCV…

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Boundary Layer of Dwarf Novae

Accretion onto WD takes place through an optically thick Keplerian disc (T~105K).

Hard X-rays are radiated from the Boundary Layer which is optically thin/geometrically thick with T~108K. The rotation speed of WD at its surface is usually much smaller than vK(R*) (~5000km/s). For settling down onto the white dwarf, accreting matter is decelerated from vK to v* by converting its Keplerian kinetic energy into heat.

Understanding of BL is not yet enough on various aspects such as size, density, geometry (2-dim or 3-dim) etc…

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SS Cyg with Chandra HETG• Lines are broad in Outburst.• If BL is like a cooling flow,

the line originates in a radially falling spherical shell.

Line profile becomes rectangular rather than a simple broad Gaussian.

• Need info of iron to discriminate in/out flow.

We need NeXT calorimeter.

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Okada et al. (2006)Okada et al. (2006)