The Luminosity Function of Galaxies in the Las Campanas Redshift Survey

We present the $R$-band luminosity function for a sample of 18678 galaxies, with average redshift $z=0.1$, from the Las Campanas Redshift Survey. The luminosity function may be fit by a Schechter function with $M^* = -20.29 \pm 0.02 + 5 \log h$,$\alpha = -0.70 \pm 0.05$,and$\phi^* = 0.019 \pm 0.001
h^3$Mpc$^{-3}$,forabsolutemagnitudes$-23.0 \leq M - 5 \log h \leq -17.5$. We compare our luminosity function to that from other redshift surveys; in particular our normalization is consistent with that of the Stromlo-APM survey, and is therefore a factor of two below that implied by the $b_J\approx 20$ bright galaxy counts. Our normalization thus indicates that much more evolution is needed to match the faint galaxy count data, compared to minimal evolution models which normalize at $b_J\approx 20$. Also, we show that our faint-end slope $\alpha =-0.7$, though ``shallower’’ than typical previous values $\alpha =-1$, results primarily from fitting the detailed shape of the LCRS luminosity function, rather than from any absence of intrinsically faint galaxies from our survey. Finally, using [OII] 3727 equivalent width $W_{\lambda }=5$~\AA \ as the dividing line, we find significant differences in the luminosity functions of emission and non-emission galaxies, particularly in their $\alpha$ values. Emission galaxies have Schechter parameters $M^* = -20.03 \pm 0.03 + 5 \log h$and$\alpha = -0.9 \pm 0.1$, while non-emission galaxies are described by $M^{\ast }=-20.22\pm 0.02+5\log h$ and $\alpha = -0.3 \pm 0.1$. (abridged abstract)