Characterization of M51 supernovae remnants with the imaging spectrometer SITELLE

Billy Gamache ( Université Laval )

We present a detailed 3D study of supernova remnants in the nearby spiral M51 using data from the SIGNALS survey obtained with the imaging Fourier transform spectrometer SITELLE at the Canada-France-Hawaii telescope. Data cubes covering the entire galaxy with a sampling of 0.32′′ /pixel were gathererd in three spectral ranges: SN3 (R = 5000 for Hα, [NII]λλ6548,84 and [SII]λλ6717,31), SN2 (R = 1000 for Hβ and [OIII]λλ4959, 5007) and SN1 (R = 1000 for [OII]λ3727). The relatively high spectral resolution of the SN3 cube allows a precise, spatially resolved measurement of the velocity dispersion of each object. While most of the SNRs were known from previous surveys based on imagery and long-slit spectroscopy, we now provide 2D line flux and kinematical maps for all of them and found 18 new candidates. Line ratios other than the traditional [SII]:Hα are presented and discussed. Most of the SNRs show velocity dispersions (σ) in the range 30−80 km/s, which is typical for middle-aged SNRs; in some cases, the approaching and receding caps are resolved. The mean value of the [NII]:Hα of 2.15 ± 0.12. This is significantly higher than usual ratios found in other spiral galaxies, but is expected given the high metallicity of M51. Finally, we compare the properties of SNRs with those of thousands of HII regions included in the same data cubes.