The luminosity function of Lyα emitters at 2.3 z

We have used VIsible MultiObject Spectrograph Integral-Field Unit (VIMOS-IFU) obser- vations centred on a radio galaxy at z = 2.9 to search for Lyemitters within a comov- ing volume of � 10 4 Mpc 3 . We find 14 Lyemitters with flux > 1.4 × 10 −20 W m −2 , yielding a comoving space density of 0.0018 +0.0006 −0.0005 Mpc −3 . We fit a Schechter luminos- ity function which agrees well with previous studies both at similar redshift (z � 3.4) and higher redshift (z � 5.7). We therefore find no evidence for evolution in the properti es of Lyemitters between 3 < z < 6, although our sample is small. By summing the star- formation rates of the individual Lyemitters we find a total cosmic star-formation rate den- sity ofSF R = 6.7 ± 0.5 × 10 −3 M⊙yr −1 Mpc −3 . Integrating over the luminosity function for the combined Lysurveys at z � 3.4 and accounting for the difference in obscuration between the Lyline and the UV-continuum yields an estimate ofSF R � 2.2 × 10 −2 M⊙yr −1 Mpc −3 , in line with previous multi-colour and narrow-band surveys of high-redshift