2022MNRAS.516.6055R

We present observations of the optical and X-ray emission from the Galactic supernova remnant W51C. From [S II] Fabry-Pérot interferometry and H α and [S II] images we detect filaments that are part of the optical counterpart of the supernova remnant. We obtain the kinematic distance to W51C, showing that it is one of the shortest distances reported in the literature. We also estimate other physical properties such as the velocity of the shock induced in the cloudlets emitted at optical wavelengths and the electron density of those cloudlets. From XMM-Newton observatory archival data, we obtain images of the diffuse X-ray emission of this supernova remnant. The spectrum of the X-ray emission is explored to estimate X-ray parameters such as luminosity and temperature of the hot plasma in the supernova remnant. We fit a thermal model with a plasma temperature of 1.4 keV for an X-ray thermal luminosity of 2.0 × 10³⁶ erg s^–1. With the parameters described above we test the model proposed by White & Long to explain the mixed morphology observed in W51C. We obtain an initial energy of the supernova explosion of 8.4 × 10⁵⁰ erg and an age of 13 000 yr. The derived initial energy is typical of supernova remnants, but in disagreement with respect to older estimations that found higher values and suggested that W51C was the result of the explosion of two supernovae.