MUSE spectroscopy of the ULX NGC 1313 X-1: a shock-ionised bubble, an X-ray photoionised nebula, and two supernova remnants

Understand

The presence of large ionised gaseous nebulae found around some ultraluminous X-ray sources (ULXs) provides the means to assess the mechanical and radiative feedback of the central source, and hence constrain the efficiency and impact on the surroundings of the super-Eddington regime powering most of these sources.

• NGC 1313 X--1 is an archetypal ULX which has been reported to be surrounded by abnormally high [O I]$\lambda$6300/H$\alpha >$ 0.1 ratios and for which high-resolution spectroscopy in X-rays has hinted the presence of powerful outflows.
• We report observations taken with the Multi-Unit Spectroscopic Explorer of NGC 1313 X--1 in order to confirm the presence of a nebula inflated by the winds, investigate its main sources of ionisation and estimate the mechanical output of the source.
• We detect a bubble of 452 $\times$ 266\,pc in size, roughly centred around the ULX, which shows clear evidence for shock ionisation in the outer edges.