Deciphering
Multi-wavelength Phenomenaof Supernova Remnants
through Numerical Modeling
Herman Lee
ITY Fellow
ISAS/JAXA

Some slides with preliminary results are skippedThis talkWhatʼs hot about SNRs
Numerical modeling of SNR emission
Young shell-type SNRs with strong shocks
Older radiative SNRs with slow cloud shocks

Future telescopes and models
2Supernova Remnants
Exciting retirement life for stars(but typical retirement age is quite high)Cassiopeia A

Neutron star!
Age: 340 yr
Radius: 2.5 pc
Distance: 3.4 kpc

Debris of 	

white dwarf star(s)Tycho’s
SNR~2.5’
Debris of 	

massive star

SN Type II, Ib, Ic	

-Massive stars run out of fuel	-Collapse itself by self-gravity	-Rebound of proto-NS, explode 	(assisted by neutrino?)	

-Bonus: a neutron star / black holeIR

Age: 440 yr
Radius: ~3.7 pc~8’No neutron star...

Distance: ~3 kpc

SN Type Ia	

-White dwarf (WD) stars in binary	-Accrete matter from companion 	

star, or merge with another WD	

-Exceed Chandrasekhar Mass (?)	-Thermonuclear explosion3Supernova Remnants
Exciting retirement life for stars(but typical retirement age is quite high)Cassiopeia A

Neutron star!
Age: 340 yr
Radius: 2.5 pc
Distance: 3.4 kpc

Debris of 	

white dwarf star(s)Tycho’s
SNR
IR

~2.5’

ESN

~8’

51
~10 erg

Debris of 	

massive star

SN Type II, Ib, Ic	

-Massive stars run out of fuel	-Collapse itself by self-gravity	-Rebound of proto-NS, explode 	(assisted by neutrino?)	

-Bonus: a neutron star / black holeAge: 440 yr
Radius: ~3.7 pc

No neutron star...

Distance: ~3 kpc

SN Type Ia	

-White dwarf (WD) stars in binary	-Accrete matter from companion 	

star, or merge with another WD	

-Exceed Chandrasekhar Mass (?)	-Thermonuclear explosion3Supernova Remnants (SNR)✦

Age from ~100 (“historic”) to >50,000 yr old✦

Much fainter than SNe, only detectable from nearby✦

Resolved objects = fun to look at!

✦

Many diﬀerent shapes (morphological types)✦

Mostly multi-wavelength (radio, IR, optical, X, gamma)✦

Release heavy elements into ISM (r-process?)✦

Compress ISM, trigger star formation, metallicity✦

Cosmic-ray factories!?

4Anatomy of an SNR

5

Undisturbed
ISM or windAnatomy of an SNR

5

Undisturbed
ISM or wind

Cold ejecta
material

Anatomy of an SNR

5

Undisturbed
ISM or wind

a
lasm

ked p

Shoc

Cold ejecta
material

Anatomy of an SNR

5

Undisturbed
ISM or wind

ds
k

hoc

Anatomy of an SNR

war

For

a
lasm

ked p

Shoc

Cold ejecta
material

5Undisturbed
ISM or wind

ds
k

hoc

Anatomy of an SNR

war

For

a
lasm

ked p

Shoc

ck
se shoRever

Cold ejecta
material

5

(R
ol
ad ec
io
u
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r
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em lo
u
is
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si
on
)

ds
k

hoc

Anatomy of an SNR

war

For

a
lasm

ked p

Cold ejecta
material

Shoc

ck
se shoRever

M

Undisturbed
ISM or wind

5

ds

(R
ol
ad ec
io
u
12
la
r
C
O
C
em lo
u
is
d
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on
)

war

For
k

hoc

a
lasm

ked p

Cold ejecta
material

Shoc

ck
se shoRever

M

Undisturbed
ISM or wind

You are looking at the projection of a shell-like object

Anatomy of an SNR

5Anatomy of an SNR

6Infrared emission
Hot dust (~102 K)
Shocked interstellar/ejecta dust

Anatomy of an SNR

6Infrared emission
Hot dust (~102 K)
Shocked interstellar/ejecta dust

Thermal X-ray
Very hot plasma (~108 K)
Shocked debris of exploded star

Anatomy of an SNR

6

Non-thermal X-ray
Synchrotron radiation
Ultra-relativistic electrons

Infrared emission
Hot dust (~102 K)
Shocked interstellar/ejecta dust

Thermal X-ray
Very hot plasma (~108 K)
Shocked debris of exploded star

Anatomy of an SNR

6

IR/optical lines
Balmer shocks
Radiative shocks

Non-thermal X-ray
Synchrotron radiation
Ultra-relativistic electrons

Infrared emission
Hot dust (~102 K)
Shocked interstellar/ejecta dust

Thermal X-ray
Very hot plasma (~108 K)
Shocked debris of exploded star

Anatomy of an SNR

6

IR/optical lines
Balmer shocks
Radiative shocks

Non-thermal X-ray
Synchrotron radiation
Ultra-relativistic electrons

Radio emission
Synchrotron radiation
Mildly relativistic electrons

Infrared emission
Hot dust (~102 K)
Shocked interstellar/ejecta dust

Thermal X-ray
Very hot plasma (~108 K)
Shocked debris of exploded star

Anatomy of an SNR

6

IR/optical lines
Balmer shocks
Radiative shocks

Non-thermal X-ray
Synchrotron radiation
Ultra-relativistic electrons

Radio emission
Synchrotron radiation
Mildly relativistic electrons

Gamma-ray emission
Sites of particle acceleration
Diﬀusive Shock Acceleration (DSA)

Cosmic rays factory!
Infrared emission
Hot dust (~102 K)
Shocked interstellar/ejecta dust

Thermal X-ray
Very hot plasma (~108 K)
Shocked debris of exploded star

Anatomy of an SNR

6

Non-thermal emission at young SNRs
= presence of fast-and-furious particles
SNR of SN1006（S. Fujiwara, 明月記, 1180-1235）
Discovery of synchrotron X-rays 	

at young shell-type SNR	→ local >100 TeV electrons
Usually accompanied by γ-rays	

→ There are high-energy particles	

ASCA
Koyama+ 1995!

TeV γ-rays SNRs are cosmic particle accelerators	

!

X-ray
H.E.S.S.	

Chandra

Q: What are these particles, how are
they accelerated, and how much	

A: Origin of Galactic CR

Naumann-Godo+ 2008

7

Synchrotron X-ray from SNRs
Not so trivial
RX J1713, twinkling X-ray dots

Vela Jr., X filaments 	

Tycho, X-ray stripes

NW rimTime
Uchiyama+ 2007

Bamba+ (2005), Pannuti+ (2010)

Eriksen+ 2011

B-ﬁelds play a central role in high-energy phenomena in SNRs and other accelerators
Time variability and spatial structures (dots, ﬁlaments, stripes) tied to B-ﬁeld
distribution
These B-ﬁelds must be self-generated (via CR-induced instabilities), plus MHD
turbulence8Mysterious radio and X-ray structures	

Origin of morphology still unclear
ChandraTychoʼs SNR

Reynoso+ (2009)
X-ray filaments = fast synchrotron loss of e- ?	

• But why in radio too? 	

• Decay of δB behind shock?	

• Periodic stripes: dominant length scales of δB?
•

9B-field geometry and DSA	From radio polarization
SN1006
G

al

ac
tic

ba
ck B0
gr
ou
nd

B0 seems parallel to shock
normal at synch-bright rims	

• DSA preferred at quasi-parallelshock !?
•

Polarization degree

ﬁe
l

d

VLA+ATCA

1.4GHzReynoso+ 2013

10

G

al

SN10060herm

al parallel to shock
B0 seems
normal at synch-bright rims	

• DSA preferred at quasi-parallelshock !?
•

“Polar-cap geometry”
ba
ck B0
gr
ou
nd
theﬁ
rem
ld
B0

al

no
n-

th

er

ma
l

ac
tic

no
n-

th

0

er
ma
l

B-field geometry and DSA	

From
radio
polarization
Bt
B

Polarization degree

B0?

VLA+ATCA
1.4GHzParticle acceleration site highly-dependenton 	

orientation
Reynoso+2013 of B0

10

Particle acceleration at non-relativisticcollisionless shock
Multi-D hybrid sim.

Caprioli & Spitkovsky 2014

(particle ion, ﬂuid electron)!

DSA at parallel vs
oblique shocks

B0!
Self-generation of δB

by CR-induced instability
indicates eﬃcient DSA

turbulent B-ﬁeld
vshockB80o0o

MS = 5080o

MS = 500o11Origin of VHE γ-ray
X-ray (image) vs TeV (contour)of SNR RX J1713

T. Tanaka+ 2008
Color: X-ray (Suzaku XIS)Contour: TeV (H.E.S.S.)

Non-thermal SNRs (e.g. RX J1713, Vela Jr.)
Amazing match of X-ray and TeV γ-ray 	

Hard γ-ray spectrum → inverse Compton?	

Same origin for γ-ray and X-ray?	

So-called ‘leptonic’ scenario	

HL+ 2012	

Non-detected thermal X-ray supports leptonic origin
12Origin of VHE γ-ray
X-ray (image) vs TeV (contour)of SNR RX J1713

T. Tanaka+ 2008
Color: X-ray (Suzaku XIS)Contour: TeV (H.E.S.S.)

Non-thermal SNRs (e.g. RX J1713, Vela Jr.)
Amazing match of X-ray and TeV γ-ray 	

Hard γ-ray spectrum → inverse Compton?	

Same origin for γ-ray and X-ray?	

So-called ‘leptonic’ scenario	

HL+ 2012	

Non-detected thermal X-ray supports leptonic origin

…but!

12

Gas maps imply shock-cloud interaction
SNR RX J1713

Vela Jr.

12CO

TeV

21cm HIY. Fukui+ 2012

Clumpy clouds around shock	• CR ions should interact with clouds	

• Spatial correlation of γ-ray and gas	

• Hadronic (π0 decay) contribution to γ-rays?	

• Probably not pure leptonic origin of γ-rays	

• Hadronic + leptonic: what proportion?
•

13

Evolved (older) SNRs
ʻOld-schoolʼ radiative shocks

Cygnus Loop
Hα O[III]
14

Radiative Shocks at
Evolved SNRs
Evolved SNRs often interacting with clouds
Typical properties:kcovsk > ~100 km/s<n0> ~ 100-1000 cm

m
to

-3

5

A

ic

sh

SNR IC443

WISE

T ~ a few 10 K behind shock, molecules
dissociated and ionized, fast radiative cooling
Photoionization precursor by UV fromdownstreamk

Bright optical/IR lines from recombining/deexcitation of gas
Spots of OH masers from dense clumps behindshocks transverse to line-of-sight

2MASS

u

c
Mole

hoc
s
r
la

Infrared images

15

Detection of Bright Radio andγ-rays
Bright non-thermal emission there(despite evolution and slow shock
velocities)
Fermi LAT found GeV-bright SNRs
inside our Galaxy(often ʻmixed morphologyʼ mid-ages)radio

X (thermal)

AGILE (γ-ray)Fermi LAT

Luminous GeV γ-ray emission
0
If all from π origin ̶>
50<ngas WCR> ~ a few 10
Lots of CR protons!?

52-3

to 10 erg/cm

Bright non-thermal radio emission
̶> <B> >> μG (i.e. >> ISM level)

See e.g. review by Slane, Ellison+ SSR 2014

SNR W44, Yoshiike+ 201316

Characteristicγ-ray spectra
Fermi LAT detects cutoﬀ around0
250 MeV ̶> π origin of γ

Mysteries remain:
Origin of copious energetic proton,
DSA injection and eﬃciency
ʻWeirdʼ CR spectra with PL break
Bright radio shell (despite age)pStage of evolution?
Connection with young (ejecta-γFunk, Tanaka, Uchiyama
Fermi LAT, Science ʼ13
See Uchiyama-sanʼs talkdominated and TeV-bright) SNRs
17

γ-rays from young to old

Different progenitors and environments	

• An evolution picture requires systematic
modeling of each type of SNR	Castro, HL+ 2014 (in prep)•18

Numerical Modeling ofBroadband Emission of SNRs

Shigehiro Nagataki

Dan Patnaude

Don Ellison

Pat Slane19Radiative

Ejectacooling

model

Conduction(SNe sim.)

Te Tion equil.
etc

20Ejecta model
Nucleosynthesis
Element mixing
Mass loss

Iterative
Work Flow
CR-hydro
Model

Initial conditions

Multi-λ Obs.

Constraints!

Dynamics, NLDSA,
B-ﬁeld, ionization, radiation 21

CR spectra from non-linear DSA
HL, Ellison & Nagataki (2012)

Thermal distribution
CR spectrum at forward shock
Spectra at different
locations in precursor

p

e-

22

CR spectra from non-linear DSA
HL, Ellison & Nagataki (2012)

Thermal distribution
CR spectrum at forward shock
Spectra at different
locations in precursorpe-Coulomb

Adiabatic

Synch(MFA=fast)22

CR spectra from non-linear DSA
HL, Ellison & Nagataki (2012)

Thermal distribution
CR spectrum at forward shock
Spectra at different
locations in precursor

p

Synch
(MFA=fast)ng pCoulomb

Adiabatic

Escapie-

22

CR spectra from non-linear DSA
HL, Ellison & Nagataki (2012)

Thermal distribution
CR spectrum at forward shock
Spectra at different
locations in precursor

heat exchange
thermal X-ray
ionization

p

e-

22

CR spectra from non-linear DSA
HL, Ellison & Nagataki (2012)

Thermal distribution
CR spectrum at forward shockheat exchange
thermal X-ray
ionization

Spectra at different
locations in precursor

p

e-Kep

22

CR spectra from non-linear DSA
HL, Ellison & Nagataki (2012)

Thermal distribution
CR spectrum at forward shockheat exchange
thermal X-ray
ionization

Spectra at different
locations in precursor

p

pmax

e-Kep

22

Broadband Model of Young SNRse.g. Slane, HL+ (2014) Tychoʼs SNR (440 yr old)23

Broadband Model of Young SNRse.g. Slane, HL+ (2014) Tychoʼs SNR (440 yr old)
Dynamics

23

Broadband Model of Young SNRse.g. Slane, HL+ (2014) Tychoʼs SNR (440 yr old)
Dynamics

Broadband spectrum

X
GeV
TeV
Radio

23

Broadband Model of Young SNRse.g. Slane, HL+ (2014) Tychoʼs SNR (440 yr old)
Dynamics

Broadband spectrum

Chandraspace resolved
X-ray spectrum

X
GeV
TeV
Radio

Red: model
Data points: CXO

23

Broadband Model of Young SNRse.g. Slane, HL+ (2014) Tychoʼs SNR (440 yr old)
Dynamics

ECR = 0.16 ESN
n0 = 0.3 cm-3
Broadband spectrum
B0 = 5μG
B2 = 180μG

Chandraspace resolved
X-ray spectrum

X
GeV
TeV
Radio

Red: model
Data points: CXO

23

Broadband Model of Young SNRs
Slane, HL+ (2014) on Tychoʼs SNR
Radial brightness proﬁle
rad

io s
ync

h

VLA

X-ray

X-ray

Model

h
c
n

y
a
-r
X

sy

Radio

24

Broadband Model of Young SNRs
HL+ (2013) on Vela Jr.

Slane, HL+ (2014) on Tychoʼs SNR
Radial brightness proﬁledata: H.E.S.S.

rad

io s
ync

h

VLA

TeV γ-ray

X-ray

X-ray

Model

h
c
n

y
a
-r
X

sy

Radio

H.E.S.S.

24

How about the thermal X-rays
TFe
Tp

log(Temperature [K])

Thermal X-rays of young SNRs tell us
many things
Ejecta and CSM chemical composition
Temperatures (ions, e-)
Ionization states

Te

TFe
Te

Even CR acceleration history

We then synthesize detailed thermal X-ray
spectrum, together with non-thermalTime

HL, Patnaude+ (2014)

Thermonuclear

Si XIIIlog(Ion fraction)

We follow non-equilibrium ionization andtemperature evolution of 140 ion species
in ejecta/CSM

Core-collapse

Si XIIRSR [RRS]

CD

25

Synthesis of detailed X-ray spectra
HL, Patnaude+ (2014)

DDT Type Ia ΔE = 7 eV
Fe-L
O
Si
S Ca
S
Mg
Ar

0.3 keV

1 keV

Fe-K

10 keV26

Synthesis of detailed X-ray spectra
HL, Patnaude+ (2014)

DDT Type Ia ΔE = 7 eV
Fe-L
O
Si
S Ca
S
Mg
Ar

0.3 keV

1 keV

Fe-K

10 keV
26

Future X-ray spectroscopy by Astro-H
RX J1713
non-thermal PL only(Suzaku)pred

ΔE = 7 eViction0.3keV

Vela Jr.

for S

XS

ASCA

12keV

HL+ 2013
0.3keV27
12keV

Our model predicts detection of resolved thermal lines from non-thermal
SNRs by SXS to reveal progenitors and CSM properties
XMM Newton etc. may detect thermal bump (see work by S. Katsuda+)
But only SXS can extract detailed info

Synergy of next-generation telescopes
for SNR studies

28

Synergy of next-generation telescopes
for SNR studies

Best X-ray spectroscopy	

• Chemical composition	

• Progenitor 	

• SN explosion properties	

• Nucleosynthesis 	• Matter mixing	• Line profiles: gas dynamics,
temperatures	

• Hard X-ray imaging 	• Injection of CR electrons	• Secondary emission

28

Synergy of next-generation telescopes
for SNR studies

Best X-ray spectroscopy	

• Chemical composition	

• Progenitor 	

• SN explosion properties	

• Nucleosynthesis 	• Matter mixing	• Line profiles: gas dynamics,

Best VHE γ-ray imaging	• New γ-ray SNRs	

• Spectrum 20GeV to >100 TeV	• Measure max E of CRs	• 3x better imaging to contrast
radio/IR/X-ray images

temperatures	

• Hard X-ray imaging 	• Injection of CR electrons	• Secondary emission

28

Synergy of next-generation telescopes
for SNR studies

Best X-ray spectroscopy	

• Chemical composition	

• Progenitor 	

• SN explosion properties	

• Nucleosynthesis 	• Matter mixing	• Line profiles: gas dynamics,

Best VHE γ-ray imaging	• New γ-ray SNRs	

• Spectrum 20GeV to >100 TeV	• Measure max E of CRs	• 3x better imaging to contrast
radio/IR/X-ray images

Next-gen IR weaponry	• MIR and FIR mapping of CSM
and ejecta, molecules and dust	

• NIR atomic lines (e.g. Fe II)	• Dust formation/destructionand SNR environment

temperatures	

• Hard X-ray imaging 	• Injection of CR electrons	• Secondary emission

28

Synergy of next-generation telescopes
for SNR studies

Best X-ray spectroscopy	

• Chemical composition	

• Progenitor 	

• SN explosion properties	

• Nucleosynthesis 	• Matter mixing	• Line profiles: gas dynamics,

Best VHE γ-ray imaging	• New γ-ray SNRs	

• Spectrum 20GeV to >100 TeV	• Measure max E of CRs	• 3x better imaging to contrast
radio/IR/X-ray images

Next-gen IR weaponry	• MIR and FIR mapping of CSM
and ejecta, molecules and dust	

• NIR atomic lines (e.g. Fe II)	• Dust formation/destructionand SNR environment

temperatures	

• Hard X-ray imaging 	• Injection of CR electrons	• Secondary emission

28

Synergy of next-generation telescopes
for SNR studies

Best X-ray spectroscopy	

• Chemical composition	

• Progenitor 	

• SN explosion properties	

• Nucleosynthesis 	• Matter mixing	• Line profiles: gas dynamics,
temperatures	

• Hard X-ray imaging 	• Injection of CR electrons	• Secondary emission

Best VHE γ-ray imaging	• New γ-ray SNRs	

• Spectrum 20GeV to >100 TeV	• Measure max E of CRs	• 3x better imaging to contrast
radio/IR/X-ray images

Next-gen IR weaponry	• MIR and FIR mapping of CSM
and ejecta, molecules and dust	

• NIR atomic lines (e.g. Fe II)	• Dust formation/destructionand SNR environment

Fermi, H.E.S.S., … (CR p)
Suzaku, Chandra, … (CR e, B, plasma, gas motion)
Nanten-2, Mopra, AKARI, ALMA, … (gas & dust)28

Summary
SNRs never end to challenge us with its many puzzling phenomena
Multi-fold astrophysical importance, e.g. origin of CRs, chemicalenrichment and turbulence in ISM, late evolution of massive stars,
SN explosion mechanism, nucleosynthesis, etc…
Treasure troves of fundamental physics, e.g. collisionless shocks,
particle acceleration, magnetic turbulence, hydro instabilities,
plasma physics etc…
A true understanding of SNRs from engine to remnant requires
confrontation of data from new telescopes with improving
numerical models

29