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arXiv · 1109.2868

Unraveling the Geometry of the Crab Nebula's "Inner Ring"

Martin C. Weisskopf·Ronald F. Elsner·Jeffery J. Kolodziejczak·Stephen L. O'Dell·Allyn F. Tennant
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Abstract

Chandra images of the Crab Nebula resolve the detailed structure of its "inner ring", possibly a termination shock where pulsar-accelerated relativistic particles begin to emit X radiation. Analysis of these images finds that the center of the ellipse-presumably a circular ring in projection-lies about 0.9" (10 light-days at 2 kpc) from the pulsar's image, at a position angle of about 300{\deg} (East of North). This analysis also measures properties of the ellipse: The position angle of the semi-major axis is about 210{\deg} (East of North); the aspect ratio, 0.49. In a simple-albeit, not unique-de-projection of the observed geometry, a circular ring is centered on the axis of symmetry of the pulsar wind nebula. This ring is not equatorial but rather lies near +4.5{\deg} latitude in pulsar-centered coordinates. Alternative geometries are briefly discussed.

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Martin C. Weisskopf, Ronald F. Elsner, Jeffery J. Kolodziejczak, Stephen L. O'Dell, Allyn F. Tennant. 2011-09-13. Unraveling the Geometry of the Crab Nebula's "Inner Ring". https://doi.org/10.1088/0004-637x%2F746%2F1%2F41

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