1996/02/29 by Huan Lin, H. Lin, Robert P. Kirshner +8 · 281 citations
Engineering · Physics and Astronomy · #Absolute magnitude #Astronomical Observations and Instrumentation #Astronomy #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminosity #Luminosity function #Normalization (sociology) #Physics #Redshift #Redshift survey #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.1086/177300
published in The Astrophysical Journal 464, 60 (IOP Publishing) · 41 pages, including 13 postscript figures, uses AASTEX v4.0 style files. Important clarification of R-band definition, plus correction of luminosity densities and updated references. Main conclusions unchanged. Final version to appear in ApJ
arxiv created 1996/04/28 · openalex publication_date 1996/06/01 · arxiv updated 2016/08/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present the r-band luminosity function for a sample of 18,678 galaxies, with average redshift z = 0.1, from the Las Campanas Redshift Survey (LCRS). The luminosity function may be fitted by a Schechter function with M^*^ = -20.29+/-0.02+5 log h, α = -0.70+/-0.05 and φ^*^ = 0.019+/-0.001 h3^ Mpc-3^, for absolute magnitudes -23.0 <= M - 5 log h <= -17.5 and h = H0_/(100 km s-1^ Mpc-1^). Over the same absolute magnitude range, the mean galaxy density is 0.029 +/- 0.002 h3^ Mpc-3^ for a volume extending to cz = 60,000 km s-1^. We compare our luminosity function to that from other redshift surveys; in particular, our luminosity function normalization is consistent with that of the Stromlo-APM survey and is therefore a factor of 2 below the normalization implied by the bJ_ ~ 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 that normalize at bJ_ ~ 20. Also, we show that our faint-end slope α = -0.7, though "shallower" than typical previous values α = - 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, we find that the faint end of the luminosity function is dominated by galaxies with emission lines. Using [O II] λ3727 equivalent width W<SUB>lambda</SUB>_ = 5 A as the dividing line, we find significant differences in the luminosity functions of emission and nonemission galaxies, particularly in their α values; emission galaxies have Schechter parameters M^*^ = -20.03 +/- 0.03 + 5 log h and α = -0.9 +/- 0.1, while non-emission galaxies are described by M^*^ = -20.22 +/- 0.02 + 5 log h and α = -0.3 +/- 0.1. The average [O II] λ3727 equivalent widths do not change significantly with redshift, consistent with a star formation rate that stays constant over the depths sampled by the LCRS. This result holds for galaxies of different luminosities and over the respective redshift ranges that these galaxies may be observed, in particular up to about z = 0.2 for galaxies brighter than M^*^.