by the SNR shock while the filaments are probably composed of both shocked wind material and shocked supernova (SN) ejecta. The distribution of filaments may indicate that the SN explosion in 11p2 was asymmetric as in Cassiopeia A. Our results support the suggestion that 11p2 is a remnant of a SN IIL/b interacting with a dense red supergiant wind.'
author:
- 'Bon-Chul Koo'
- 'Dae-Sik Moon'
- 'Ho-Gyu Lee and Jae-Joon Lee'
- Keith Matthews
title: 'and filaments in the Supernova Remnant G11.2$-$0.3: Supernova Ejecta and Presupernova Circumstellar Wind'
---

Introduction
============

G11.2$-$0.3 is a composite-type SNR with a central pulsar wind nebula (PWN) surrounded by a circular shell. The shell is bright both in radio and X-rays, and has an outer diameter of $4'$ and a thickness of $0.'5$ [@gre88; @rob03]. The shell is clumpy with several clumps protruding its outer boundary. The bright radio shell with high circular symmetry indicates that the remnant is young and it is thought to be the best candidate for the possible historical supernova of AD 386 [@ste02]. The PWN with an associated pulsar was discovered at the very center of the remnant in X-rays with [*ASCA*]{}, and later its detailed structure was 