Experimental High energy Astrophysics using satellite-borne X-ray instruments

Kazuo Makishima Department of Physics, University of Tokyo Research Center for the Early Universe, U. Tokyo Inst. of Physical & Chemical Research (RIKEN)

Physics and Astrophysics of Compact Stars

2012/12/15 1 QUCS2012 at Nara

2012/12/15 QUCS2012 at Nara 2

(1-1)Atmospheric Transparency

photoelectric

Compton

molecular bound e’s free e’s

CO2

Ozone

rotation vibration

Height

Pres

sure

(1-2) Discovery of a Cosmic X-ray Source (1962)

2012/12/15 QUCS2012 at Nara 3

Optical ID, first in Japan, then at Palomar; (Sandage, Giacconi, ...,,, Oda, Osawa, Jugaku 66)

M. Oda (right) and his modulation collimator Thin

Win.

Thick Window

Moon Mag. F. vector

N E S W N

(Giacconi+62)

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§2. X-ray Satellites

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 J

US

ESA R

Hinotori Yohkoh Hinode MAXI

ASTRO-H

HETE-2 SAS-3

ANS (蘭) Ariel-5 (英)

Ariel-6 (英) EXOSAT (ESA) ROSAT

(独)

Copernicus (米英)

Uhuru OSO-7 OSO-8

HEAO-1 Einstein

Rossi XTE Swift

NuSTAR Chandra

BeppoSAX (伊)

XMM-Newton (ESA)

INTEGRAL (ESA+露)

ASTRON Mir/Kvant GRANAT

Hakucho Tenma

Ginga ASCA Suzaku

Cosmic X-ray

Share with γ-ray etc. Space Station Japanese Solar

2012/12/15 QUCS2012 at Nara 5

The Instrumentation Team for the HXD (Hard X-ray Detector) on-board Suzaku (launched in 2005)

Construction of Ginga (launched in 1987)

Some Pictures ..

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c, e, h, mp , me , G, (ε0) Two important dimensionless constants:

• Fine structure constant (EM interaction strength) • Grav. f.s. const. (gravitational interaction strength)

• For any celestial object, αG:α = self-gravitating energy : Coulomb repulsion energy (if not neutral)

The only macro variable: mass M (or N ≡ M /mp)

§3. Beauty of Astrophysics How macro properties of celestial objects described via first principle using fundamental constants

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1

(3-1) Stellar Mass-Radius Relations

0.01

0.1

0.001

Jup Sat Nep

Ura

mass M (Solar unit)

Radi

us R

(So

lar

unit)

1 0-3 0.01 0.1 1 1 0-４

interior Chandrasekhar

mass

1

: Bohr radius

Supported by Coulomb repulsion

Compton wavelength

Supported by e- degeneracy

10

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(3-2) Temperature of Accreting Matter

0.1 1 10 100 103 104 105 106

GeV

MeV

keV

Compact Object Mass (M◎)

Tem

pera

ture

of a

ccre

ting

mat

ter

Neu

tron

Sta

rs

pump-up via jets etc.

Black Holes

ions: Free-fall temperature e-: Heated by ions, while Compton cooled by soft photons

2012/12/15 QUCS2012 at Nara 9

(3-3) Temp. of accretion disks around BHs

A BH of mass M radiating at η(0<η<1) times the Eddington limit:

Thomson cross sect.: Stefan-Boltzmann’s law: S-B constant: Innermost radius (GR)： Disk temperature at the innermost radius:

(Shakura & Sunyaev 1973)

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§4. Computational Astrophysics

1. Physical settings cannot be chosen as you like Strong spatial gradients, Non steady-state, Explosive/Transient, Versatile processes, …

2. Extreme (often exotic) physical conditions ρ＞ρnuc, kT > mec2, G.R., B > 4.4×1013 G, etc., where our knowledge may be insufficient…

3. Long-range force (Grav, EM) + local interactions Strong non-linearity, Self-interaction, Energy non-equipartition, Spont. struct. formation, …

2012/12/15 QUCS2012 at Nara 11

Typical Results

Core-collapse supernovae (Bruenn+12)

Formation of a protostar in very early universe (Yoshida+07)

Structure formation in CDM universe (Abel+12)

Matter accretion onto a black hole (Ohsuga+09)

2012/12/15 QUCS2012 at Nara 12

§5. Neutron Stars (NSs)

mas

s（M

◎)

Raius（km)

An ultra-compact star, in which the extreme gravity (109g) is supported by degenerate pressure of neutrons.

Formed by core collapse of a massive star. MNS~ 1.4 M◎,

RNS〜N1/3rnuc〜10 km, ρ〜ρnuc or higher

The MNS vs. RNS relation is sensitive to the nuclear EOS.

(5-2) Suzaku Spectra of Compact Objects

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Energy (keV)

NS; R BH; G

NS; Mag.

The rest = NS; G

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§6. NS Magnetism S

urfa

ce M

ag. F

ield

(G)

0.001 0.01 0.1 1 10 100 1000 Rot. Period (sec)

10 15

10 14

10 13

10 12

10 11

10 10

10 9

Radio pulsars

Accreting XR pulsars

Magnetars Aged magnetars？ Long per. pulsars？

ms pulsars XR bursters

Rotation Gravity Mag. F.

Energy source

B is estimated assuming that the NS spins down by emitting M2 radiation

2012/12/15 QUCS2012 at Nara 15

About half of ~40 known accreting binary X-ray pulsars have allowed detections of electron cyclotron resonance features (Landau level transisions) in their spectra (Makishima +99), at an energy of keV.

Her X-1 (Enoto+08)

Ea=28 keV B=2.4e12G

fundamental

5 10 20 30 50 100

200 Energy (keV)

X0331+53 (Nakajima +10)

2nd harmonic

Energy (keV)

Ea=37 keV B=3.2e12G

(6-1) Electron Cyclotron Resonances

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msec pulsaras

(6-2) Evolution of NS MFs: a revolution in the 1990’s

No evidence for MF decay

Accreting pulsars radio pulsars (Itoh+95)

Born with weak MF? Phase transition from strongly mag. NSs?

Birth

Magnetars (Duncan+Thompson 95)

1 ms 10ms 0.1s 1s 10s 100s 1 ks Rotation Period P

1015

1014

1013

1012

1011

1010

109

108

Mag. Field B(G

) recycle

Cyclotron measurements

Mag. fields of NSs are a manifestation of Nuclear ferromagnetism? (Makishima+99; theor. support by Hashimoto, Hatsuda+12)

2012/12/15 QUCS2012 at Nara 17

§7. Puzzles of Magnetars Isolated NSs with no evidence of mass accretion. Sometimes

emitting repetitive intense soft gamma-ray flashes. About 25 known. From P and dP/dt, B=10 14-15 G is suggested. X-ray lum. ≫ spin-down lum. not rotation powered. Radiating by consuming

their magnetic energies.

Suzaku peculiar 2-comp. spectra.

Emission mech. of hard component?

With age, why the hard c. gets weaker but harder?

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(7-1) Physics in ~1012 Gauss M.F. Harding, A., & Lai, D. Rep. Prog. Phys. 69, 2631 (2006)

Synchrotron/ curvature radiation

one-photon pair production

Particle acceleration by induced electric fields E =v×B = 2e14 (P/30ms)-1(B/1e12G)(R/10km)2 (V/m)

（still ≪ Schwinger limit…） energetic e’s

Strong synchrotron

radio emission

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(7-2) Physics in 1014-15 Gauss M.F.

Positron infall

Enoto+10c

cutoff expected

strong field 511

“Photon Splitting” A 3rd QED effect: a photon interact with B-

field and splits into two with lower energies. Cross section ∝ (B/Bcr)6 (hν/mec2)5, with

photon-polarization dependence. (Bialynicka-Birrla & Bialynicka-Birrla 70, Meszros & Ventura 79, Baring & Harding 01)

2012/8/30 基研 ハドロン物質の諸相 20

§8. ASTRO-H A successor to Suzaku, to be launched in 2014

Soft XR mirror＋Micro Calorimeter: 0.5-12 keV, ΔE/E~0.1% Soft XR mirrror+ ＸR CCD camera：

0.3-12 keV、Wide FOV of 40’ Super Mirror + Hard XR Imager：

5~80 keV, imaging spectroscopu Soft GR Detector：

60~600 keV, Advance Compton camera