CTA Japan meeting
Kashiwa Campus of the University of Tokyo
2016-12-16

Particle accelerationin supernova remnants
numerical simulations andhigh-energy observations
Gilles Ferrand
Research Scientist
Astrophysical Big Bang Laboratory

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Outline of the talkIntroduction: particle accelerationin supernova remnants- SNRs as Cosmic Ray accelerators
Catalogue of high-energy observations- rationale and objectives- demo and statistics
3D numerical simulations- hydro+kinetic code
- thermal and non-thermal emission

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SNRs as a key link between stars and the ISM
enrichment in heavy elementsBig Bang:
H, He

Cosmic Rays:
Li, Be, Bstars:
all other elementsfrom C to U

average stars: up to C-O
massive stars: up to Fe
supernovae: everything else?

injection of energy
heatingof the gashydrodynamic
turbulencemagnetic field
amplification

impact on subsequent
star formation cycles?

acceleration of particles
SNRs main sources?
Also PSRs and binaries< 1015 eV:
Galactic> 1018 eV:extra-Galactic

the acceleration ofcharged particles is
an important featureof magnetized shocks
in collisionless plasma1.103

Supernova Remnants as sources of Cosmic Rays
energy spectrumof cosmic radiation(as observed on the Earth)acceleration by shock waves
in supernova remnants

J standard composition
L some "anomalies"
J global energetics
L maximum energy
J power-law (Fermi 1)
L which slope? (NL effects)
J radiation fromaccelerated electrons
L and protons?
from Nagano et Watson 2000

reviews: Drury 2012, Blasi 2013, Bell 2013

SNR broad-band emission

04

A&A 516, A62 (2SN1006

λ

radio

opticalXcmµm

keV

synchrotron
in B field

Balmer lines
forbidden lines

atomic lines ofheavy elements+ synchrotron

Fig. 6datastrict0◦ co−90◦

gammaFig. 4. HESS γ-ray image of SN 1006. The linear colour scale is in unitsof excess counts per π × (0.05◦ )2 . Points within (0.05◦ )2 are correlated.
The white cross indicates the geometrical centre of the SNR obtained
from XMM data as explained in the text and the dashed circles correspond to R ± dR as derived from the fit. The white star shows thecentre of the circle encompassing the whole X-ray emission as derived
by Rothenflug et al. (2004) and the white triangle the centre derived byCassam-Chenaï et al. (2008) from Hα data. The white contours correspond to a constant X-ray intensity as derived from the XMM-Newton
flux map and smoothed to the HESS point spread function, enclosing
respectively 80%, 60%, 40% and 20% of the X-ray emission. The inset
shows the HESS PSF using an integration radius of 0.05◦ .

E

TeV

Inverse Compton ?
pion decay ?

Fig. 7regio
to theTabl

RGeV e-blast wave

hot ejecta+ TeV e-review for CR evidence: Helder et al 2012

> TeV e- ?
> TeV p ?

Fig. 5. Radial profile around the centre of the SNR obtained from HESS
data and XMM-Newton data in the 2–4.5 keV energy band smoothed toHESS PSF.

centred on −143.6◦ ± 6.1◦ (SW region) and 29.3◦ ± 4.0◦ (NEregion) and with similar widths of 33.8◦ ± 7.0◦ and 27.9◦ ± 4.0◦ .

T
pow
indic
show
correone1.105

HE catalogue of Galactic SNRs: motivation● Focus on high-energies (X, gamma)
Dave Green’s catalogue: identification and typing from radio emission
SNRcat: particle acceleration from broadband X-ray and γ-ray emission● Provide a unified view of SNRs
Some observatories offer dedicated resources
SNRcat: all observations from major relevant observatories presented together
Some other websites present all observations in a specific energy domain
SNRcat: complete and broad-band view of all Galactic SNRs
● Be up-to-date
Green’s catalogue: last updated in 2014 (294 SNRs, added 87)
SNRcat: weekly/daily updates, to keep pace with the surge in X-ray/γ-ray obs● Be easy to manipulate
SNRcat: stored in a relational database (sorting, filtering, searching,...)
Ferrand & Safi-Harb 2012 (ASR 49 9)

www.physics.umanitoba.ca/snr/SNRcat

1.106

HE catalogue of Galactic SNRs: statistics• 381 records of a supernova remnant (SNR). 108 contain a neutron star (NS) or candidate, 108 identified as a pulsar (PSR). 6 anomalous pulsars (AXPs) + 5 soft γ-ray repeaters (SGRs) + 2 high-B PSRs
= 13 magnetars candidates. 15 central compact objects (CCOs) or candidates. pulsar wind nebula (PWN) detected or suggested in 106 cases (not a subset ofthe SNRs hosting a NS: only 83 SNRs are associated with both). interaction of the shell with a molecular cloud (MC) reported in 70 cases• 14 records of the sighting of a supernova (SN)referred to by 14 SNRs records(non-bijective: some SN have multiple candidates, others have none)• 1633 records of high-energy observations made with 40 observatories
NB: 425 of these are actually non-detections
NB: the emission might not be coming from the SNR itself• 2235 references as ADS bibcodes plus 100s of other URLs
Omissions? Ideas? your feedback is welcome!

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HE catalogue of Galactic SNRs: worldwide usagewww.physics.umanitoba.ca/snr/SNRcat

first 2 years statistics (2012/02 – 2014/01)> 60,000 accesses from > 5,000 unique IPs(98% of IP addresses can be localized at country level)

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HE catalogue of Galactic SNRs: extensions
Database completeness● Instruments coverage: to be updated regularly following new results, inparticular from instruments having started operations (H.E.S.S. II, NuSTAR,ASTROSAT), satellites about to be launched (eROSITA), as well as plannednext-generation observatories (Hitomi recovery mission, CTA)
● Wavelength coverage: eventually get a full multi-wavelength view of all
SNRs, covering all regions of the electromagnetic spectrum (IR, optical, UV)● Objects coverage: can be extended to nearby LMC and SMC

User interface● maps: add an interactive map of the Galaxy● images: add images in radio and X-rays (maybe !-rays)

Samar Safi-Harb
U. of Manitoba

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Galactic SNRs in radio

montage courtesy
Jennifer West

SNRs at TeV: from HESS…

10
G347.3-00.5 = RXJ1713-3946(2004)

first imageat TeV

G266.2-01.2 = RX
J0852.0-4622 = Vela Jr(2005)

G347.3-01.0(2015)

G315.4-02.3 = RCW 86(2009)

SNR candidate(2015)

G327.6+14.6 = SN 1006
(2010)

SNR candidate(2015)

J1731-347
G353.6-00.7(2011)

discoveredin γ-rays!

H.E.S.S. Coll.
Nature 2004

H.E.S.S. Coll.
2008, 2011a new way ofdetecting andstudying SNRsa new way ofdetecting andstudying SNRs
Pühlhofer et al 2015 (arXiv:1509.03872P)
Gottschall et al 2016 (arXiv:1612.00261)

The H.E.S.S. experiment has imaged several TeV shell SNRs in the last decade.
A breakthrough for ground-based astronomy, although still a small sample.

11SNRs at TeV: …to CTA
G315.4-02.3 = RCW 86(2009)

G327.6+14.6 = SN 1006
(2010)The CTA observatory will be able to✓ detect 20-70 SNRs (most of the TeV shells currently shining in the Galaxy)✓ resolve 7-15 SNRs (depends on their distance...)Note: identification will still require MWL studies

shellsPWNs

horizons of detectability (filled symbols) and resolvability (opensymbols) for different possible configurations of the arraysimulations by Renaud 2011, also in Acero et al 2013

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2 orthogonal approaches for SNR studies→ derive statistically significant trends in the Galaxy
do a global modeling of all Galactic SNRs, by doing simpler broad-band spectral fittings

do a detailed modeling of select SNRs, by running realistic 3D numerical simulations→ study in details the physics of particle acceleration

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Diffusive shock acceleration: the coupled system
IROptUVX

radioXγshock wave
(thermal magnetizedplasma)u APF (X) = @hydrodynamictreatmenting
mpda ating
heX=@1uu ⌦ u + pI A
(e + P ) u

ge
ne
rat
ion
difsto fu(instach sionasbiltic , inj
itie
ac ects)
ce ion
ler
ati ,
on

conservation laws
X+ div (F (X)) = 0t 010

cosmic-rays(non-thermalpopulation)

injection, acceleration
shock modification

particle distribution:n (x, t) =f+(uf ) =txx

magnetic waves(collective movementsof charges)✓Zf (x, p, t) 4 p2 dpp

transport equation:fDx◆

1 p3 f u+ 2
3pp x

kinetic
treatment

reviews : Drury 1983, Jones and Ellison 1991, Malkov and Drury 2001

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Numerical simulations: hydro + kinetic
slice of log(density)from cosmology to supernova remnants(in both cases: comoving grid to factor out expansion)

Chevalier 1982, 1983

SNR initialization:
self-similar profiles
from ChevalierTeyssier 2002,
Fraschetti et al 2010

SNR evolution:
3D hydro coderamsesparameters: Tycho (SN Ia)tSN = 440 years
ESN = 1051 erg
n = 7 , Mej = 1.4 M
s = 0 , nH,ISM = 0.1 cm 3

shock
diagnostics

back-reaction:
varying gamma

Ellison et al2007

particle acceleration:
non-linear modelof Blasi
Anne
Decourchelle
CEA Saclay
Irfu/SApBlasi et al
2002, 2004, 2005
+ Caprioli 2008, 2009

Ferrand et al 2010
(A&A 509 L10)

Thermal emission from the hot plasma
Ferrand,Decourchelle,
Safi-Harb 2012(ApJ 760 34)

emissivity [erg/s/cm3/eV]

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using theemission codefrom Mewe(depends on
density,temperatureand ionisation
states)1024^3 cells
t = 500 yrenergy [eV]

test particle vs. back-reactiontest particle vs. back-reaction

test particle vs. back-reaction

Non-thermal emission from the particles

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emissivity [erg/s]

synchrotron(e)Ferrand,Decourchelle,
Safi-Harb 2014(ApJ 789 49)
pion decay (p)Inverse Compton(e)energy [eV]efficient MF
amplification➞ high B

no net MF
amplification➞ low Busing theemission codefrom P. Edmon(depends on
density andmagnetic field)
1024^3 cells
t = 500 yr

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Thermal + non-thermal emission in X-rays

modified shockwith magnetic field amplification

test-particle casesimulations

observations
Energetic protons,
accelerated at theshock front, don’t
radiate as efficiently
as electrons, however:1/ they impact thedynamics of the shock
wave, and therefore
the thermalemission from theshell (optical, X-rays)
2/ they impact theevolution of themagnetic field,
and therefore thenon-thermalemission from theelectrons (radio – Xrays – γ-rays)

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Non-thermal emission: maps at TeV energies

assuming efficient
acceleration and MFA

inverse Compton

pion decay

thermo-nuclear
supernova
type Ia in a
uniform ISM
n=7, s=0(t = 500 yr)

Ferrand andSafi-Harb 2016
core-collapse
supernova
PRELIMINARY
type II in theprogenitor’s wind
n=9, s=2(t = 300 yr)

back-reaction

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Observational perspectives with CTA
Fermi SNRs: mostly middle-aged remnants interacting with molecular clouds
H.E.S.S. SNRs: still difficult to disentangle hadronic and leptonic contributions→ we want to (finally) find the “PeVatrons”!
see the spectrum cut-off

see the shell morphology✓ wide energy range
from 20 GeV to 300 TeV✓ with sensitivity x10 @ 1 TeV✓ angular resolution ≃ 1'above 1 TeV✓ large field of view >5–8°

CTA can detect a (even small)
hard hadronic component

CTA can distinguish between hadronic andleptonic emission

upcoming CTA Collaboration paper on RX J1713.7−3946
Nakamori, Katagiri, Sano, Yamazaki, Ohira

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Modelling perspectives: the shock in context• impact of the progenitor : ejecta profiles (stratification, asymmetries)
stellar wind (for core-collapse)• impact of the environment : molecular clouds (radiative? ionized?)
ISM turbulence (hydro + mag)shock wave
progenitor’s windSN

turbulence

accelerated
particles
molecular cloudejecta profiles

Shigehiro Nagataki
Astrophysical Big Bang Laboratory
RIKEN