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Chandra View of Pulsar Wind Nebulae Torii submitted to ApJ

Chandra View of Pulsar Wind Nebulae Torii submitted to ApJ. Contents: 1. Introduction 2. PWN torus and spin-down luminosity 3. Discussion and application. Aya Bamba ISAS/JAXA -> DIAS (Oct.01). 1. Introduction. Chandra discovered torii and jets of pulsar wind nebulae !!.

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Chandra View of Pulsar Wind Nebulae Torii submitted to ApJ

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  1. Chandra View of Pulsar Wind Nebulae Torii submitted to ApJ Contents: 1. Introduction 2. PWN torus and spin-down luminosity 3. Discussion and application Aya Bamba ISAS/JAXA -> DIAS(Oct.01)

  2. 1. Introduction Chandra discovered torii and jets of pulsar wind nebulae !! What is the origin of torus ? Related to termination shock of pulsar wind ? 1/2 Edot 4pchPext rs = rs: termination shock radius Edot: spin-down energy c: light speed h: filling factor Pext: external pressure Objectives: To understand the relation between torus and termination shock. Correlation between torus radius and spin-down energy ?

  3. 2. Correlation between torus and termination shock 2.1. Torus radius Ng+04, Ng+08 developed the fitting method of 2-dimensional images of PWNe double torii -> torus information radius, angle, width, …. Crab Successfully determined parameters for ~10 PWNe Vela

  4. Our samples • 11 samples from Ng & Romani (04, 08), and Romani+05 • The radii are converted to physical size • with the latest distance estimation

  5. 2.2. Spin-down energy vs. torus radius clear correlation with correlation factor of 0.82 linear fit -> rejected due to too small errors

  6. With larger errors artificial error: delta(log r) = 0.3 log r = 0.57±0.22 log Edot – 22.3±8.0

  7. 3. Discussion (1): The origin of the correlation ? log r = 0.57±0.22 log Edot – 22.3±8.0 dependency is consistent with the termination shock ! 1/2 Pext 1.6x10-9 [g cm-2s-1] 1/2 h 1 r/rs = 1.9 (1.2-3.0) If we assume log r ~ 0.5 log Edot 1/2 Edot 4pchPext rs = (kT=1keV, n=1 cm-3) Torus radius is roughly same to that of termination shock. The origin of dispersion of delta (log r) = 0.3 delta (r) ~ factor 2 delta (Pext) ~ 40% dispersion Naturally explained by the dispersion of the external pressure

  8. Discussion (2): New method for Edot estimation log r = 0.57±0.22 log Edot – 22.3±8.0 With torus radius, we can estimate Edot without period and period derivative ! -> good Edot estimator ?? example: G0.9+0.1 One of the bright PWN No pulsation has been found In the GC region -> distance known

  9. In the case of G0.9+0.1 Gaensler+01 discovery of small-scale PWN size: 5” x 8” -> radius ~ 4 arcsec = 0.16 pc @ 8.5 kpc -> Edot = 5.3 x 1037 ergs/s one of the most energetic pulsar ! Camilo+09 (arxiv: 0906.3289) discovered pulsation at 2 GHz ! P=52ms, Pdot=1.5557x10-13s/s -> Edot=4.5x1037ergs/s Our method is valid for G0.9+0.1. We can try it with DEM L241 (Bamba+06), HESSJ1813 (Gotthelf+09),…

  10. Summary • Chandra discovered torus structure surrounding pulsars. • The spin-down luminosity and the torus radius have • very strong correlation (corr. factor = 0.82). • The relation can be written as • log r = 0.57±0.22 log Edot – 22.3±8.0 • The dispersion of the data set is ~40% • if it is due to the external pressure dispersion. • The relation is a good Edot estimator without P and Pdot.

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