Modeling the Thermal and Non-thermal
Emission of Young Supernova Remnants
Herman Lee (RIKEN)

Collaborators
Don Ellison (NCSU)	

Hiro Nagataki (RIKEN)	

Pat Slane (CfA)	

Dan Patnaude (CfA)	

Masaomi Ono (Kyushu U)	

Daniel Castro (MIT)	

Outline!

• The challenge of modeling the many facets ofSNR broadband emission	• What a physical emission model needs to account for	

• What “hurdles” from observation data it must overcome 	!

• What we can learn from the models and theirconfrontations with current+future observations2

Behold!

The Multi-wavelength Era has comeTycho’s SNRIR

X-ray 	(thermal)

IC 443IR

opticalX-ray 	(synch)

Fermi!

Thermonuclear

Fermi
Core-collapse

To build a truly successful model of SNR emission:	

Synergy of all available broadband data AND
modeling by a good physical model are the keys
3

SNRs are complex stuff

SN1006 Chandra4

SNRs are complex stuff
For young SNRs,	

all these are linked together	

in non-linear fashion!	

We need multi-λ info and 	comprehensive models
SN1006 Chandra4Any serious broadband emission model ofSNRs must overcome a number of 	

Hurdles from Observations:	

Matching FS, CD and RS radii	

Matching shock speeds (expansion rates)	

Non-thermal spectrum (radio - TeV)	

Thermal spectrum (ionization, composition) 	

Multi-λ morphology	

Spectral variation in space-time	

etc......

Our recipe to model SNR emission

HL+ 2012 ApJ6Code is inexpensive
Perfect for deep parameter search
Preliminary

Slane, HL+ submitted

First, we	search forparameter spaceconsistent withobservational facts

SNR 	shell radius
Expansion
rates
Photon flux	

Gamma-ray	X-ray	Radio	

fixed inputs
ambient density7

HL+ 2013 ApJBroadband
Spectrum

X-ray GeVRadiosynchthermal

Check consistency of: 	

ICπ0brem• Radio to TeV flux	• Spectral shapes	

• Inferred CR energetics	

• Required B-field, CSM, ESN.e pree+cursorSNR Vela Jr.

sec

But often, more than
one acceptable models exist	

(e.g. hadronic vs leptonic)

TeVesc. p8

Thermal X-ray
can constrain
Gamma-ray origin
In young SNRs, thermal
X-ray emission iscoupled to theirbroadband emission!
Very important:
Predicted thermal flux
must not exceedobserved X-ray flux	

= another constraint

HL+ 2013 ApJ
SNR Vela Jr.

Thermal lines

Thermal cont.

9Radial emission profiles probe
γ-ray origin & DSA efficiency
Radio, X-ray andTeV morphologies
all constrain CRacceleration andenergy loss history

TeV profile
Models vs H.E.S.S.	

(no fitting)

SNR Vela Jr.
CTA prediction

SNR Vela Jr.
H.E.S.S.	

Aharonian et al (2007)

HL+ 2013 ApJ 10

Hadronic andleptonic models
predict very different
spectral index
distributions	(e.g. CSM, B-field)
Kishishita & Uchiyama 2013	

XMM-Newton

X-ray Synch Index

Spectral index distribution
as a model discriminator
SNR Vela Jr.
XMM Newtontfits
BeBest-fit hadronic

cino
leptFS

Radius [RFS]
HL+ 2013 ApJ 11

Hadronic andleptonic models
predict very
SNRdifferent
Vela Jr.	

spectral
NW indexrim
distributions	(e.g. CSM, B-field)
Kishishita & Uchiyama 2013	

XMM-Newton

X-ray Synch Index

Spectral index distribution
as a model discriminator

Bamba+ (2005), Pannuti+ (2010)

SNR Vela Jr.
XMM Newton

cino
lepttfits
B~e a few μG

Requires BDS
How about filaments?
Unsettled mysteryBest-fit hadronicFS

Radius [RFS]
HL+ 2013 ApJ 11

CCIa
Preliminary
HL+ in prep

Molar fraction of elements in ejecta

Ejecta/CSM models
and synthetic X-ray spectrum
HeHOSiEjecta

Fe@500yr

CSM

Type IIb w/ RSG wind
O Fe L
NeFeHeSiSFe KO
SiFeHeType Ia (detonation) w/ ISM
SinISM = 0.2 cm-3O

Type Ia (deflagration) w/ ISM
0.3keV

12keV
12

What do we learn?

• A good broadband emission model tightly constrained by
MW observations can tell us a lot, e.g.: 	

•of SN explosion energy converted to CR at given age• Fraction(Note: CR ions always dominate total energy even for leptonic models)	

Origin of γ-rays from a SNR (CR ion, or CR e-, or a mixture)	

• Properties of ejecta, CSM, progenitor and its pre-SN winds	• We can quantify contributions of different types of SNR toGalactic CR in their lifetimes

Note: hadronic and leptonic cases often predict very different ECR	• Our models can consistently bridge state-of-the-art hydroand explosive nucleosynthesis simulations of SNe to theSNR phase by covering important (non-)thermal physics!

13

Synergy of future super telescopes
for SNR studies

Hi-res X-ray spectroscopy	• Ejecta/CSM composition from faint lines	

• Unveil progenitor properties of Ia andcore-collapse SNRs	

• SN explosion mechanisms, matter
mixing and nucleosynthesis 	• Broadened line profiles: 	

gas dynamics, temperature equilibration

Hi-sensitivity, hi-res imaging	• Many new gamma-ray SNR discoveries	• Low-noise spectrum measurementfrom ~20GeV to >100 TeV	• Measure roll-over region of CR spectra!	

• 3x better TeV morphology measurementto contrast with radio/IR/X-ray images 	14

Last remarks•

CR-hydro-NEI code is a fast/versatile code forbroadband emission calculations of SNRs•

Next target is full 3-D MHD/emission models(with essential physics inside!)Work now in progress (RIKEN/NCSU/Kyushu/…)•

Our self-consistent spherically symmetriccalculations serve as important pilot study

Additional info

CR Spectrap4 f(p)Thermal distribution

Adiabatic losspet = 100 yr
t = 1000 yr

Synch loss
Coulomb loss

Time evolutionof broadband spectrum
Tycho’s SNRRadio

X-ray

Pion decay

GeV

TeV

Slane, HL+ submitted

m’edifiplSubshock

B1 = 100 µG‘Alog (B) [G]Magnetic Field
Ampliﬁcation (MFA)

CR precursor

B0 = 3 µG

log (x/FEB)

HL+ 2012

Alfven wave damping
precursor gas heating
HL+ 2012

Subshocklog (T) [K]T1 = 1 x 107 K
Gas pre-heatedby damped
Alfven waves

x 100

fdamp = 0.50
CR precursor

10-10 LFEB

log (x/FEB)

T0 = 1 x 105 K
1 x LFEB