Supernova Remnants in the Magellanic Clouds. IX. Multiwavelength Analysis of the Physical Structure of N49

Abstract

We present a multiwavelength analysis of the supernova remnant N49 in the Large Magellanic Cloud. Using high-resolution Hubble Space Telescope WFPC2 images of Hα, [S II], and [O III] emission, we study the morphology of the remnant and calculate the rms electron densities in different regions. We detect an offset of [O III] and Hα emission peaks of about 0.5'' and discuss possible scenarios that could give rise to such high values. The kinematics of the remnant is analyzed by matching individual kinematic features in the echelle spectra obtained at the Cerro Tololo Inter-American Observatory with the morphological features revealed in the WFPC2 images. We detect a narrow Hα emission component and identify it as diffuse preshock recombination radiation, and discrete broad emission features that correspond to the shocked gas in filaments. The overall expansion of the remnant is about 250 km s-1. The dense clouds are shocked up to line-of-sight velocities of 250 km s-1, and the less dense gas up to 300 km s-1. A few cloudlets have even higher radial velocities, reaching up to 350 km s-1. We confirm the presence of the cavity in the remnant and identify the center of explosion. Using archival Chandra and XMM-Newton data, we observe the same trends in surface brightness distribution for the optical and X-ray images. We carry out a spectral analysis of three regions that represent the most significant optical features.