Multi-wavelength Properties of Supernova...
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Jacco Vink University of AmsterdamAnton Pannekoek Institute/GRAPPA
Multi-wavelength Properties of
Supernova Remnants
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
Supernova classification
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Complex CSM: - strong winds ϱ∝1/r2 -starforming regions & MCs
Simple CSM (?)But see Kepler (Chiotellis+ ’12)
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
SNR structure & evolution
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Truelove & McKee 99
●Two shock structure:• blast wave in CSM• reverse shock heating ejecta
(stellar debris)
●Once Mej
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
Non-equilibrium ionization
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●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)
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
An age sequence of Type Ia SNRs
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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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
Linking young SNRs with SNe: X-rays
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●oxygen●neon●silicon
G292.+1.8
0519-690
●Core collapse SNRs are rich in O, Ne, Mg●Type Ia SNRs are iron-rich
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
“Mature SNRs”
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●For low V/T
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
Mixed-morphology/Thermal composite SNRs
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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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
Shocks, temperatures & cosmic rays
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●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!
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
Temperature (Non-)Equilibration
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Simplified plane parallel shock model, no equilibration:
Electrons
Protons
Also scales with net!!
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
Shock heating & acceleration: 2 fluid approach
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●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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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.)
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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)
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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?
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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)
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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.
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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)
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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)
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
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Jacco Vink Multi-wavelength Observations of SNRs C Barcelona, 60th birthday of Felix Aharonian
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
Tuesday, November 6, 12