Chandra View of

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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 -gt DIAS (Oct.01)
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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 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 ?
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2. Correlation between torus and termination
shock 2.1. Torus radius
Ng04, Ng08
developed the fitting method of 2-dimensional
images of PWNe double torii
-gt torus information radius, angle, width, .
Crab
Successfully determined parameters for 10 PWNe
Vela
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Our samples

• 11 samples from Ng Romani (04, 08), and
  Romani05
• The radii are converted to physical size
• with the latest distance estimation

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2.2. Spin-down energy vs. torus radius
clear correlation with correlation factor of 0.82
linear fit -gt rejected due to too small
errors
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With larger errors
artificial error delta(log r) 0.3
log r 0.570.22 log Edot 22.38.0
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3. Discussion (1) The origin of the correlation ?
log r 0.570.22 log Edot 22.38.0
dependency is consistent with the termination
shock !
If we assume log r 0.5 log Edot
(kT1keV, n1 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
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Discussion (2) New method for Edot estimation
log r 0.570.22 log Edot 22.38.0
With torus radius, we can estimate Edot without
period and period derivative !
-gt good Edot estimator ??
example G0.90.1
One of the bright PWN No pulsation has been
found In the GC region -gt distance known
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In the case of G0.90.1
Gaensler01 discovery of small-scale PWN
size 5 x 8 -gt radius 4 arcsec
0.16 pc _at_ 8.5 kpc
-gt Edot 5.3 x 1037 ergs/s
one of the most energetic pulsar !
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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 0.570.22 log Edot 22.38.0
• 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.