Physics and Astrophysicsof Compact Stars

Kazuo Makishima

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

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

2012/12/15

QUCS2012 at Nara1(1-1)Atmospheric Transparency

PressureOzone

Heightphotoelectric

molecular
rotation vibration

CO2

2012/12/15

QUCS2012 at Narabound e’sfree e’sCompton2

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

NNEMoon(Giacconi+62)

Mag. F. vector

SWOptical ID, first in Japan, then at
Palomar; (Sandage, Giacconi, ...,,,
Oda, Osawa, Jugaku 66)
2012/12/15

M. Oda (right) andhis modulation
collimator

QUCS2012 at Nara3

§2. X-ray
Satellites

Cosmic Xray 1975
1970
JU
S
E
S
A

Share with γ-ray etc.
1980

1985

1990

Hakucho Tenm Ginga
aHinotori

Uhuru
OSO-7

SAS-3
OSO-8

2000

2010

2005

YohkohHETE-2 Hinode
ChandraEinstein

HEAO-1

Rossi XTEASTRON
Mir/Kvant

GRANAT(独)

SuzakuMAXI

ASCA

ROSAT

2012/12/15

Japanese Solar

1995

EXOSAT
Copernicus (米(ESA)(蘭)ANS 英)Ariel-6 (英)Ariel-5 (英)RSpace Station

2015
ASTRO-H
NuSTAR
Swift

XMM-Newton (ESA)
BeppoSAX(伊)QUCS2012 at Nara

INTEGRAL (ESA+露)4Some Pictures ..

Construction ofGinga (launchedin 1987)

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

2012/12/15

QUCS2012 at Nara

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

 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-gravitatingenergy : Coulomb repulsion energy (if not neutral)

The only macro variable: mass M (or N ≡ M /mp)2012/12/15

QUCS2012 at Nara

6

(3-1) Stellar Mass-Radius Relations
Radius R (Solar unit)

Supported by Coulomb repulsion
1 10.1: Bohr radiusinteriorUra

Sat Jup

Nep
Supported bye- degeneracy

Chandrasekhar
mass0.01

Compton wavelength
0.001
10-４

2012/12/15

10-30.01

0.1

mass M (Solar unit)
QUCS2012 at Nara

1107

GeV

MeVkeV

2012/12/150.1

pump-up via jets etc.
Neutron Stars

Temperature of accreting matter(3-2) Temperature of Accreting Matter

1ions: Free-fall temperaturee-: Heated by ions, while
Compton cooled by soft photons

Black Holes
10100103

104

Compact Object Mass (M◎)
QUCS2012 at Nara

1051068(3-3) Temp. of accretion disks around BHs(Shakura & Sunyaev 1973)

 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:

2012/12/15

QUCS2012 at Nara

9§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

10

Typical Results

Structure formation in CDM universe (Abel+12)

Matter accretion
onto a black hole(Ohsuga+09)

Core-collapse supernovae (Bruenn+12)
Formation ofa protostar
in very earlyuniverse(Yoshida+07)
2012/12/15

QUCS2012 at Nara

11§5. Neutron Stars (NSs) 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.

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

mass（M◎) MNS~ 1.4 M◎,
RNS〜N1/3rnuc〜10 km,
ρ〜ρnuc or higherRaius（km)2012/12/15

QUCS2012 at Nara

12(5-2) Suzaku Spectra of Compact Objects

BH; GNS; R
The rest= NS; GNS; Mag.

Energy (keV)

2012/12/15

QUCS2012 at Nara

13

15

§6. NS Magnetism

10

Surface Mag. Field (G)B is estimated assuming
14 spins downthat the10NS
by emitting M2 radiation

Magnetars
Aged magnetars？

13Long per. pulsars？

10Accreting XR pulsars

1210Energy source

Radio pulsars

1110Rotation
GravityMag. F.

1010109ms pulsars
XR bursters

0.001
2012/12/15

0.01

0.1

Rot. Period (sec)110

QUCS2012 at Nara

100100014

(6-1) Electron Cyclotron Resonances
About half of ~40 known accreting binary X-ray pulsars haveallowed detections of electron cyclotron resonance features(Landau level transisions) in their spectra (Makishima +99), atan energy ofkeV.
fundamental
2 ndharmonic

Ea=28 keV
B=2.4e12G

Ea=37 keV
B=3.2e12G

X0331+53(Nakajima +10)

5Energy (keV)
2012/12/15

QUCS2012 at Nara

Her X-1 (Enoto+08)
1020 30 50
200100

Energy (keV)15

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

1015

1013
1012
1011
1010
109
108

Mag. Field B(G)Cyclotron
measurements

1014

Magnetars (Duncan+Thompson 95)
No evidence
for MF decay

Birth Accreting pulsars
radio pulsars(Itoh+95)
recycleBorn with weak MF?
Phase transition fromstrongly mag. NSs?

msec
pulsaras

Mag. fields of NSs are a manifestation ofNuclear ferromagnetism? (Makishima+99;
1 ms 10ms 0.1s
1s 10s 100s 1 ks
theor. support by Hashimoto,Hatsuda+12)
Rotation Period P

2012/12/15

QUCS2012 at Nara16§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. ofhard component?
 With age, why thehard c. gets weaker
but harder?
2012/12/15

QUCS2012 at Nara17

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

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

one-photon pair
production

Synchrotron/
curvature radiation

Strongsynchrotron
radio emission
2012/12/15

QUCS2012 at Nara18

(7-2) Physics in 1014-15 Gauss M.F.
“Photon Splitting”
 A 3 rd QED effect: a photon interact with Bfield and splits into two with lower energies.
 Cross section ∝ (B/Bcr)6 (hν/mec2)5, withphoton-polarization dependence.

(Bialynicka-Birrla & Bialynicka-Birrla 70, Meszros &Ventura 79, Baring & Harding 01) cutoff expected
Positron infall

Enoto+10c
2012/12/15

strong field

QUCS2012 at Nara511
19§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 Comptoncamera

2012/8/30

基研

ハドロン物質の諸相20