2019MNRAS.489.3042A

We have carried out optical observations of the northeastern part of the supernova remnant IC 443 using the Canada-France-Hawaii Telescope imaging spectrograph SITELLE. The observations consist of three multispectral cubes covering an 11' x 11' area allowing the investigation of both the spatial and spectral variation of nine emission lines: [O II] λλ3726 + 3729, [O III] λλ4959, 5007, H β, H α, [N II] λλ6548, 6583, and [S II] λλ6716, 6731. Extinction measurement from the H α/ H β shows significant variation across the observed region with E(B - V) = 0.8-1.1. Electron density measurements using [S II] lines indicate densities ranging from 100 up to 2500 cm^–3. Models computed with the shock modelling code MAPPINGS are presented and compared with the observations. A combination of complete shock model and truncated ones is required in order to explain the observed spectrum. The shock velocities found in IC 443 are between 20 and 150 km s^–1, with 75 km s^–1 being the most prominent velocity. The pre-shock number density varies from 20 to 60 cm^–3. A single set of abundances close to solar values combined with varying shock parameters (shock velocity, pre-shock density, and shock age) is sufficient to explain the great variation of line intensities observed in IC 443. Despite the relatively modest spectral resolution of the data (R ∼ 1500 at H α), we clearly separate the red and blue velocity components of the expanding nebula, which show significant morphological differences.