MUSE Analysis of Gas around Galaxies (MAGG) - V. Linking ionized gas traced by C IV and Si IV absorbers to Ly emitting galaxies at z 3.0-4.5

We study the connection between Ly aemitters (LAEs) and metal-enriched ionized gas traced by C IV absorption at redshift z approximate to 3-4 in 28 quasar fields with high-resolution spectroscopy from the MUSE Analysis of Gas Around Galaxies survey. In a sample of 220 C IV absorbers, we identify 143 LAEs connected to C IV gas within a line-of-sight separation +/- 500 km s(-1), equal to a detection rate of 36 +/- 5 per cent once we account for multiple LAEs connected to the same absorber. The luminosity function of LAEs associated with absorbers has an approximate to 2.4 higher normalization than the field. The analysis of the LAE-C IV correlation function suggests that metal-enriched gas arises both in the haloes of the LAEs and from locations not connected to galaxies. C IV absorbers with higher equivalent width are more often associated with LAEs and C IV systems are twice less likely, especially at low equivalent width, to be found near LAEs than strong H I absorbers. The covering fraction in groups is up to approximate to 3 times larger than for isolated galaxies. Similar results are found using Si IV as tracer of ionized gas. We propose three components to model the gas environment of LAEs: (i) the circumgalactic medium of galaxies, accounting for the strongest correlations between absorption and emission; (ii) overdense gas filaments connecting galaxies, driving the excess of LAEs at a few times the virial radius and the modulation of the luminosity and cross-correlation functions for strong absorbers; (iii) an enriched and more diffuse medium, accounting for weaker C IV absorbers farther from galaxies.