Transcript M.Ishida_Future_HE_Mission2006 - X

Diagnostics of thermal plasma with
eV-level Resolution
Manabu 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/XMMNewton.
 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
• H-like
• resonance
 Ly1 : 2P1/2 → 2S1/2
 Ly2 : 2P3/2 → 2S1/2
• forbidden (f)
 z : 3S1 → 1S0
B
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Density diagnostics with He-like triplet
Ishida (1995)
Porquet et al (2001)
r
i
f
• 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.
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nc(Z) = 6.75 (Z-1)11.44 cm-3
He-like triplet as a density probe
CVs
T Tau star
Solar coronaStellar flare Proto star
Tm(Z) = 8320
(Z-0.4)2.71 K
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Density measurement of AE Aqr with XMM RGS
Itoh et al. (2006)
• AE Aqr (mCV, Pspin = 33.08s, Porb = 9.88h, B = 105-6G ?)
• ne~1011cm-3, lp = (2-3)x1010cm
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What’s happening in AE Aqr ?!
• In the accretion column of mCV
 ne~1016cm-3, lp ~107cm, whereas
ne~1011cm-3, lp = (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
Wynn & King (1997)
• 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.
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Origin of the GRXE
• Thin thermal: kTmax ~ 7keV.
• Diffuse ?
 Ebisawa et al. (2005)
Suzaku XIS
6.4keV
• 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.
B
Thanks 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+(z1).
• 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 Helike ion.
 IE: additionally with Li-like ion.
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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 12
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
B
 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.
Okada et al. (2006)
B
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