Multi-wavelength Properties of Supernova...

Jacco Vink University of AmsterdamAnton Pannekoek Institute/GRAPPA

Multi-wavelength Properties of

Supernova Remnants

Tuesday, November 6, 12

Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian

Supernova classification

2

Complex CSM: - strong winds ϱ∝1/r2 -starforming regions & MCs

Simple CSM (?)But see Kepler (Chiotellis+ ’12)



SNR structure & evolution

3

Truelove & McKee 99

●Two shock structure:• blast wave in CSM• reverse shock heating ejecta

(stellar debris)

●Once Mej


Non-equilibrium ionization

4

●Densities in SNR plasmas low (ne=0.01-100 cm-3)●Plasmas recently shocked (~100-~10000 yr)⇒often not enough time to reach equilibrium ionization (ion. rate=recomb. rate)



An age sequence of Type Ia SNRs

55

SNR 0509 SNR 0519 Dem L71

●Chandra images (Fe in green)●XMM/RGS high resolution X-ray spectra

Evolutionary sequencehigher Fe ionization, more Fe is shocked (reverse shock further in)

Warren et al. 2004Kosenko, et al.2008Van der Heyden 2002



Linking young SNRs with SNe: X-rays

6

●oxygen●neon●silicon

G292.+1.8

0519-690

●Core collapse SNRs are rich in O, Ne, Mg●Type Ia SNRs are iron-rich



“Mature SNRs”

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●For low V/T


Mixed-morphology/Thermal composite SNRs

8

W28 (ROSAT/VLA)

●Mixed-morphology SNRs are centrally bright in X-ray and shell-type in radio●X-ray emission (center) is thermal, and often enhanced in abundances●Evidence for over-ionization! →adiabatic cooling (e.g Yamaguchi+ ’09) ●Idea: shell too cool for X-rays, but center hot enough for X-rays (Cox+ ’99)●Shell bright in radio (compressed electron cosmic rays, vd Laan mechanism?)●Many associations with masers

-Many MM SNRs detected by Fermi/Agile- W28 has offset HESS source: CR escape(Aharonian c.s. ;91,96, ’01,....)

W44AGILE: Guiliani+ ’11



Young versus Old SNRs in radio

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SN1006 PKS1209-51

●Radial magnetic fields●Emission due to recently accelerated electrons

●Tangential magnetic fields●Flux can be explained by Van der Laan mechanism (compression of pre-existing electron cosmic rays)

Dickel & Milne ‘96



Shocks, temperatures & cosmic rays

10

●A strong shock in a monatomic gas heats the plasma to

kTi =2(γ − 1)

(γ + 1)2miV

2

s =3

16miV

2

s = 2.0( mi

mp

)( Vs1000 km/s

)2

keV

●For young SNRs (Vs>3000 km/s) expect kT > 10 keV●No SNR known with kT > 4 keV!!●Possible solution: non-equilibration: electrons are colder than protons!●Alternative: efficient cosmic ray acceleration (e.g. Hughes+ ‘00)●X-rays: measure in general electron temperature not proton temperature!



Temperature (Non-)Equilibration

11

Simplified plane parallel shock model, no equilibration:

Electrons

Protons

Also scales with net!!



Proton temperatures

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Ghavamian+ ‘07

Comparing electron and proton temperatures●Proton temperature:

thermal Doppler broadening of Hα

●Electron temperature:X-ray spectra

●Tprotons > Telectrons only for Vs> 300 km/s



Shock heating & acceleration: 2 fluid approach

13

●Standard shock continuity relations with some modifications:- Three regions 0: far upstream;1: precursor, just upstream of main shock; 3: shocked gas- cosmic ray pressure continuous from 2-3- cosmic rays can escape (no energy flux conservation!)

012



Shock heating and compression

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Compression ratio Energy/cosmic ray escape

●Agrees with kinetic/monte carlo simulations (Ellison, Blasi, Jones)- disadvantage: have to assume adiabatic index- advantage: no assumption on how particles are accelerated

●Efficiency (cr pressure/total pressure):w =

(1� ��g1 ) + �gM20⇣1� 1�1

⌘

1 + �gM20⇣1� 1�12

⌘ ⇡1� 1�11� 1�12



Limits on particle acceleration

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●For relativistic dominated particles (γ=4/3): Mach nr M > 5.88●Relaxed for non-relativistic cosmic rays to M > √5=2.24●Note different behavior of curves for γ=4/3 and γ=5/3

(no solutions with low w and low escape)●No efficient acceleration for M


Plasma Temperatures

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correction w.r.t. standard standard result

kT =316

mV 2s

Post-shock temperatures much lower in cosmic-ray dominated shocks

Vink et al. 2010



X-ray synchrotron filaments

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●Cas A ●Kepler●Tycho

●SN 1006

•All historical shell SNRs emit X-ray synchrotron (1st detected SN1006: Koyama et al. ‘95)

• Implies Emax,electron ~ 10-100 TeV• Requires fast shocks (hνmax~0.5(V/2000)2η-1keV -> Aharonian&Atoyan ’99)

• Emission regions often narrow (few “)•Given rapid cooling times -> active accelerations •Evidence for small diffusion coefficients (rapid acc.)



X-ray synchrotron profiles

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●Fits with spherical models with exponential synchr. emissivity profiles●Fits not that well (except Vela Jr)

Helder,JV,+ 12



Interpreting narrow X-ray rims

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●Rim widths determined by interplay diffusion, advection and synchrotron losses

●Combining diffusion and advection:

●Rim width can be used to measure B-field: B ≈ 110 (L/1017cm)-2/3 μG

●Cas A/Tycho/Kepler: ~100-500 μG (Vink&Laming 03, Berezhko+ ’03, Völk+ 04, Bamba+ 04, Warren+ 05, Parizot+ 06, Helder+ 12)

●High B ⇒fast acceleration ⇒ protons beyond 1015eV?•High B-field likely induced by cosmic rays (e.g. Bell ‘04)•High B-fields are a signature of efficient acceleration

length scale = �v�syn /�v

B2E

h�ch = 13.9⇣ B?

100 µG

⌘⇣ E100 TeV

⌘2keV

Vink&Laming ‘03

B2 ⇡ 26⇣ ladv

1.0⇥ 1018cm

⌘�2/3⌘1/3

⇣�4 �

14

⌘�1/3µG



Tycho’s SNR (western rim)

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exponential profileuniform shell profileexponential profile+ precursor

●Exponential profile not a good fit●Much better (but still preliminary):

-add synchrotron precursor (with X=2.5)- requires small B-field jump ⇒ sub-shock with low compression- alternatives: deviations from spherical symmetry

Vink 2012See also Bamba+ ’04



Acceleration @ Cas A reverse shock

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●Spectral index: 2 regions of hard emission: X-ray synchrotron emission●Deprojection: Most X-ray synchrotron from reverse shock!●Surprising: ejecta should have low magnetic field!●Prominence of West: No expansion ⇒ ejecta shocked with V>6000km/s

Deprojection

Γ= -3.2

Final amplified B-field insensitive to initial field!?Helder&Vink ’08Uchiyama+ ‘08

4-6keV



Magnetic Field Amplification

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●There is a clear correlation between ρ, V and B, in rough agreement with theoretical predictions (e.g. Bell 2004)

●Relation may even extend to supernovae (B2∝ρVs3 ?) (Völk+ ‘05, Vink ‘08)



X-ray synchrotron decline of Cas A

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●X-ray synchrotron flux (4-6 keV) declines strongly:Whole SNR: −(1.5 ± 0.17)% yr−1Western part: −(1.9 ± 0.10)% yr−1Accompanied by steepening of spectral index Γ

●Critical check: no decline in line rich band (1.5-3 keV)no 4-6 keV decline cluster A1795

Patnaude, Vink, Laming, Fesen, 2011

d�cdt

= �4r

�c�

�cd�dt

1F (�)

dF (�)dt

= �2d�dt

●Decline more than in radio: not adiabatic cooling●Likely cause: shock deceleration

●Confirms basic interpretation of synchrotron model●Decline somewhat high, may imply small diffusion coefficient, hence very fast acceleration



Heating vs Acceleration

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•GeV/TeV + X-ray synchrotron: particles accelerated to high energies (but not yet the “knee” or beyond)

•CR efficiency seems to be near or below required 10% efficiency of total expl. energy•Contradicts other signs of efficient acceleration:

•B-field amplification, high compression ratios (Tycho), curved spectra•What about another consequence of efficient acceleration: low plasma temperatures?



Balmer lines from non-radiative shocks

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●Neutral hydrogen entering shock:- direct ionization → no line emission- excitation followed by ionization → narrow line hydrogen emission- charge exchange (H+p →p+H*) → H* has kT of shocked plasma

●May also be important for shock-precursor (Alfven damping)! (Raymond ’11,Blasi+ ’12)

Thermal X-ray

Fig: Eveline Helder

X-ray synchrotron

Compression/pre-heating

Thin layer (~1015 /np cm):neutrals excite, charge X-change, ionize

Heng 2010



Hα from X-ray synchrotron region RCW 86

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Vink+ 06

X-ray (XMM)

●RCW 86 likely SN185●RCW 86 is a TeV source, but not GeV (Aharonian+ 08, Lemoine-Goumard+ 12)●Non-radiative H-α emission from several shock locations in RCW 86●Faint H-α associated with X-ray emitting region in NE -> suggests high Vshock●VLT H-α spectroscopy: FWHM=1100 ± 63 km/s ⇒ kTp = 2.2 keV●X-ray expansion measurement: Vs = (5900±1200) d2.5 km/s●Discrepancy: >50% shock acceleration efficiency (Helder, JV+ 09)



New expansion measurement RCW 86

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●New expansion measurements based on two H-α images (‘07-2010)●Two regions NE (X-ray synchrotron) and SE (no X-ray synchrotron)●Both regions same H-α width -> same plasma temperature●H-α proper motion for NE H-α filament ~1400 d2.5km/s●For SE similar but somewhat lower●Conclusion:

- no need for (very) efficient acceleration- puzzle: why does NE (low density) have X-ray synchrotron and SE (denser) not?- was X-ray proper motion wrong, or is H-α from denser, slowed down regions?

Helder, JV+ in prep.



H-ɑ from fastest known SNR shock

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●Distance known (LMC, 50 kpc)●Shock velocity: X-ray line broadening + Chandra expansion: Vs> 5000 km/s●One of the fastest shocks in a known SNR●J.P. Hughes private communication Vs=6500 km/s●H-alpha broad line widths: 2680 ± 70 km/s (SW), 3900 ± 800 km/s

Helder, Kosenko, Vink ‘10

SNR 0509-675 (LMC)



LMC SNR 0509-675

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-Inferred CR fractional pressure SW: w>15%, -But perhaps w >50% if indeed Vs=6500 km/s-Needed: better models for Hα emission with cosmic rays (see Blasi+ 2012)

●Southwest: kTp=16 keV, expect ~50 keV

Curves: model by Van Adelsberg+ ‘08

Helder, Kosenko, Vink ‘10

Preliminary! (Arne de Laat master’s thesis)



GeV emission from young SNRs

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●Recall: Broad spectral range needed for distinguishing leptonic vs hadronic radiation

●Fermi detected several young SNRs: Cas A, Tycho, RX J1713,...RX J1713 ->leptonic domination likely Cas A -> undecidedTycho -> hadronic likely

●Only Tycho seems to have ~10% of energy in CRs (e.g. Aciari+ ’11, Morlino&Caprioli ’12)

RX J1713 (Fermi)

Abdo+ ’10

Cas A

Abdo+ ’11Giordano+ ’12

Tycho



Cas A versus Tycho

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●Cas A may have been/be the better accelerator!●Escape likely important●Escape in Cas A in 1/r2 profile: less interactions of cosmic rays

�(R) = constant ⇥(R) =Ṁ

4�R2vw

Core collapse (SN II(b))Type Ia

●Density structure

●Emission from escaped CRs(with diffusion radius Rd)L�0 /

Z Rdiff

0ncrnH(R)4�R2dR

- In stellar winds: Luminosity evolution 1) total number of CRs 2) decreases with time Rd ~t1/2- Type Ia: emission only depends on Ncr, surface brightness limits detection- For Tycho pion decay emission may come partly from ambient medium!

L⇡0 / NcrnH L⇡0 / 3NcrṀw/(vwR2di�)

Vink ’12 (arXiv:1206.2363)Tuesday, November 6, 12


Summary

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●Supernova remnants are interesting in many ways:- explosion physics- chemical evolution- plasma physics - cosmic-ray acceleration

●Multi-wavelengths aspects important for all:- Gamma-rays: see many other talks during this conference:- X-rays:

• thermal: composition, electron temperatures, ionization• synchrotron:

-proof of active acceleration-B-field amplification or even creation (talk by Tony Bell)

- Optical observations (H-alpha)• some evidence for low temperatures: non-linear acceleration• more modeling needed


Multi-wavelength Properties of Supernova...

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