Chandra View of Pulsar Wind Nebulae Torii submitted

Chandra View of Pulsar Wind Nebulae Torii submitted to Ap. J Contents: 1. Introduction 2. PWN torii 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 !! What is the origin of torus ? Related to termination shock of pulsar wind ? rs = Edot 4 pch. Pext 1/2 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.

2. Correlation between torus and termination shock 2. 1. Torus radius Ng+04, Ng+08 PWNe fitted with torus + jet Crab Vela 2 -dimensional fit -> torus information radius, angle, width, …. Successfully determined parameters for ~10 PWNe

Our samples Ø 11 samples from Ng & Romani (04, 08), and Romani+05 ØThe radii are converted to [pc] with the latest distance estimation

2. 2. Spin-down energy vs. torus radius clear correlation with correlation factor of 0. 82 linear fit -> rejected due to too small errors

With larger errors delta(log r) = 0. 3 log r = 0. 57± 0. 22 log Edot – 22. 3± 8. 0

3. Discussion (1): The origin of the correlation ? h r/rs = 1. 9 (1. 2 -3. 0) 1 1/2 Pext 1. 6 x 10 -9 [g cm-2 s-1] 1/2 (k. T=1 ke. V, 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

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: G 0. 9+0. 1 One of the bright PWN No pulsation has been found In the GC region -> distance known

In the case of G 0. 9+0. 1 Gaensler+01 discovery of small-scale PWN size: 5” x 8” -> radius ~ 4 arcsec = 0. 16 pc -> Edot = 5. 3 x 1037 ergs/s one of the most energetic pulsar ! Camilo+09 (arxiv: 0906. 3289) discovered pulsation at 2 GHz ! P=52 ms, Pdot=1. 5557 x 10 -13 s/s -> Edot=4. 5 x 1037 ergs/s Our method is valid for G 0. 9+0. 1.

Summary ØChandra discovered torii structure surrounding pulsars. ØThe spin-down luminosity and the torus radius have very strong correlation (corr. factor = 0. 82). ØThe relation can be written as log r = 0. 57± 0. 22 log Edot – 22. 3± 8. 0 ØThe dispersion of the data set is ~40% if it is due to the external pressure dispersion. ØThe relation is a good Edot estimator without P and Pdot.