摘要：Context.In recent years, Lyαnebulae have been routinely detected around high redshift, radio-quiet quasars thanks to the advent of the highly sensitive integral field spectrographs. Constraining the physical properties of the Lyαnebulae is crucial for a full understanding of the circum-galactic medium (CGM). The CGM acts both as a repository for intergalactic and galactic baryons as well as a venue of feeding and feedback processes. The most luminous quasars are privileged test-beds to study these processes, given their large ionising fluxes and dense CGM environments in which they are expected to be embedded.Aims.We aim to characterise the rest-frame ultraviolet (UV) emission lines in the CGM around a hyper-luminous, broad emission line, radio-quiet quasar atz ∼ 3.6, which exhibits powerful outflows at both nuclear and host galaxy scales.Methods.We analyse VLT/MUSE observations of the quasar J1538+08 (Lbol = 6 × 1047erg s−1), and we performed a search for extended UV emission lines to characterise its morphology, emissivity, kinematics, and metal content.Results.We report the discovery of a very luminous (∼2 × 1044erg s−1), giant Lyαnebula and a likely associated extended (75 kpc) CIV nebula. The Lyαnebula emission exhibits moderate blueshift (∼440 km s−1) compared to the quasar systemic redshift and a large average velocity dispersion (σ¯v∼ 700 km s−1) across the nebula, while the CIV nebula shows average velocity dispersion ofσ¯v∼ 350 km s−1. The Lyαline profile exhibits a significant asymmetry towards negative velocity values at 20−30 kpc south of the quasar and is well parametrised by the following two Gaussian components: a narrow (σ ∼ 470 km s−1) systemic one plus a broad (σ ∼ 1200 km s−1), blueshifted (∼1500 km s−1) one.Conclusions.Our analysis of the MUSE observation of J1538+08 reveals metal-enriched CGM around this hyper-luminous quasar. Furthermore, our detection of blueshifted emission in the emission profile of the Lyαnebula suggests that powerful nuclear outflows can propagate through the CGM over tens of kiloparsecs.
