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Koyama and Bamba Non-thermal Filaments from SNR
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1.Introduction of X-ray study of cosmic ray acceleration in SNRs 2.Chandra observation of SN 1006 3.Discussion of acceleration parameters; time scale, magnetic field, and maximum energy of electrons 4.Application to other SNRs 5.Summary 6.Hints for observations of SNRs interacting with molecular clouds
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1. Introduction “How are cosmic rays accelerated up to TeV?” Basic concept: Diffusive Shock Acceleration (DSA) (Bell 1978; Blandford & Ostriker 1978…) Koyama et al.(1995) Discovery of sync. X-rays from the shell of SN 1006 Next: More direct measurements Spatial and spectral capability of Chandra SN1006: type Ia d=2.18kpc 10 ´ B, E max, distribution of electrons on the shock….. SNRs with sync. X-rays More sample SNRs
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2.1. Chandra Image and spectrum How wide are the non-thermal filaments? 0.3 – 2.0 keV 2.0 – 10.0 keV inward = downstream outward = upstream SN1006 NE shell Energy (keV) 1 5 0.3 thermal extended non-thermal sharp (Bamba et al. 2003)
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2.2. Properties of the Filaments 1. Width of non-thermal X-ray filaments Distance : 2.18 kpc (Winkler et al. 2003) w u = 0.01- 0.1pc w d = 0.06 - 0.4pc Scale length of nonthermal X-rays arcsec upstreamdownstream wdwd counts 0 20 40 0 20 40 2.0 – 10.0 keV wuwu shock 2. Wide band spectrum (SRCUT model) ν roll = (2.6±0.7)×10 17 Hz Reynolds & Keohane (1999)
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u u = 4u d =2890 km/s m.f.p. of e = r g 3.1. Discussion: three time scales 1. t age : The age of SN 1006 ~ 10 3 years 2. t loss : energy loss time scale (synch. loss) 3. t acc : acceleration time scale ~ > 1 dB B -2 shockB up down E max, B
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3.2. From equations to parameters A. Age limited case B. Loss limited case t acc = t age < t loss t loss = t acc < t age w u = K u /u u w d = K d /u d w u = min {K u /u u, (K u t cool ) 1/2 } w d = max {u d t cool, (K d t cool ) 1/2 } unknown parameters: E max, B u, B d, u, d, known parameters: u u, rolloff, w u,w d B d = B u (cos 2 + r 2 sin 2 ) 1/2 lolloff ~ BE 2 d < u Both cases, Restriction of parameters!
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3.2.A. Age limited case: t acc =t age <t loss w u =K u /u u, w d =K d /u d dd w u = 0.01-0.1pc w d = 0.06-0.4pc B d ~ 78 G E max = 22-29TeV d<ud<u uu = 0 o t acc <t loss
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On the other angle…. d ~ 1 B d = 14 – 78 G E max = 22 – 69 TeV uu = 60 o = 30 o dd dd = 90 o uu
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3.2.B. Loss limited case: t acc =t loss <t age w u = min {K u /u u, (K u t cool ) 1/2 } w d = max {u d t cool, (K d t cool ) 1/2 } < 30 o, d ~ u ~ 1 B d = 23 – 85 G, E max ~ 21 – 54 TeV = 30 o uu = 0 o uu dd
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Age limited case; d ~ 1 B d = 14 – 78 G E max = 22 – 69 TeV Loss limited case; < 30 o d ~ u ~ 1 B d = 23 – 85 G E max = 21 – 54 TeV In the future, B d : fully turbulent (Bohm limit) 14 – 85 G B u : 3.5 – 85 G E max : 20 – 70 TeV Anyway, More detailed models Multi-wavelength obs. accurate accel. history CANGAROO suggests B ~ a few G. (Tanimori et al. 2001) 3.3. Given restrictions for SN 1006 shockB updown In age limited case!
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4.1. Application to the other SNR Is SN1006 the lonely SNR with non-thermal filaments? ……No! Vink & Laming (2003) found non- thermal filaments in Cas A Cas A 1 ‘= 1 pc Spatial resolution of Chandra w d =0.024 pc +0.004 -0.003 w u =0.017 pc +0.002 -0.002
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Tycho Hwang et al. (2002) 30“ = 0.3pc w d =0.079 pc +0.012 -0.009 w u =0.015 pc +0.002 -0.002 “filaments with small E.W.” =3.1 +0.3 -0.2 The filament is non-thermal!
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Kepler 30“ = 0.7pc +0.007 -0.006 w d =0.019 pc w u =0.024 pc +0.008 -0.007 w d =0.069 pc +0.017 -0.012 w u =0.038 pc +0.015 -0.011 =2.3 +0.2 -0.2 =2.2 +0.2 -0.2 Energy (keV) 1510 Energy (keV) 1510 Thin & non-thermal Filaments!! =2.3 +0.2 -0.2
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4.2. The scale length vs. radius 251050 Radius of SNR (pc) 10 -2 10 -1 1 Scale length (pc) downstream upstream The scale length is ~ % of the radius. The scale lengths grow larger as the SNRs age. Cas A 30 Dor C RCW 86 SN 1006 Kepler Tycho
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5. Summary 1.Non-thermal and thin filaments are discovered at the outer edge of SN1006. 2.The scale length is very small, w u = 0.01 – 0.1 pc and w d = 0.06 – 0.4 pc. 3.Both in age limited case and loss limited case, we can make restrictions such as; magnetic field in downstream is turbulent. electrons are accelerated to 20 – 70 TeV. 4.We found thin non-thermal filaments in many SNRs. 5.The filaments glow wider as SNRs age older.
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6. Hints for observations of SNRs interacting with MCs G347.3-0.5, W28, RCW 86…. RCW 86 G347.3-0.5 What determines the scale length?
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4. Application to other SNRs Do other SNRs have non-thermal filaments? Cas AKeplerTycho 0.02pc 0.04pc 0.007pc 0.02pc 0.06pc 0.01pc Many SNRs have thin filaments!
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