Detection of Hα emission associated with the z_abs = 2.304 ESDLA towards J0025+1145. Top panels: three individual 2D spectra and the combination of all of them. The quasar trace has been removed over the central region (Δv ∼ 3000 km s⁻¹). The Hα emission corresponds to the remaining blob in the centre of the images, and is quite evident in the combined 2D spectrum. The side panels show the spatial extent of the trace (black) and of the Hα emission (red) obtained by collapsing the 2D data along the wavelength axis. The location of their centroid (horizontal dotted lines) provides a measure of the impact parameter along the slit direction. The fifth panel shows the quasar-subtracted 1D data (in blue) summed over the spatial axis together with a Gaussian fit (in red) to the emission line. The normalised absorption profile of Fe IIλ2260 is shown in the bottom panel for comparison. The absorption seen at v ∼ −1600 km s⁻¹ is due to Fe IIλ2249.