2004A&A...417..487C

This paper presents observations of an extended Lyman-α emission nebula surrounding the galaxy responsible for the Damped Lyman-α Absorption (DLA) line in the spectrum of the quasar Q2233+131. With the Potsdam Multi Aperture Spectrophotometer (PMAS) we measure the properties of the extended Lyα emission in an area of 3''x5'' having a total line flux of (2.8±0.3)x10^–16erg/cm²/s, which at redshift z=3.15 corresponds to a luminosity of (2.4_–0.2^+0.3)x10⁴³erg/s and a size of 23x38kpc. The location of the emission is spatially coincident with the previously detected DLA galaxy, but extends significantly beyond its limb. We argue that the Lyα emission is likely to be caused by an outflow from the DLA galaxy, presumably powered by star formation. In the case of negligible dust extinction, the Lyα luminosity indicates a star-formation rate of 19±10M_☉/yr consistent with that derived from the UV continuum flux from the parent galaxy. The wind velocity indicated by the integral field spectra is of the order of several hundred km/s. We find no indication of emission originating in a rotating disk.