The Power Spectrum of Galaxy Clustering in the Las Campanas Redshift Survey

Abstract

The Las Campanas Redshift Survey (LCRS) contains 23697 galaxies, with an average redshift $z=0.1$, distributed over six $1.5\arcdeg$ by $80\arcdeg$ slices in the North and South galactic caps. We have computed the power spectrum $P(k)$ for LCRS galaxies over wavelengths $\hat{I}»=2\ddot{I}€/k=5-400h^{-1}$~Mpc. The LCRS $P(k)$ may be approximated as $\propto k^{-1.8\pm 0.1}$ for small scales $\hat{I}»=5-30h^{-1}$~Mpc, changing to $\propto k^{1\pm 1}$ for large scales $\hat{I}»\approx 200-400h^{-1}$~Mpc. The overall amplitude corresponds to $\ddot{I}{ƒ}_8=1.0\pm 0.1$ in redshift space. Comparisons to the power spectra of other redshift surveys will be presented; the LCRS results agree best with those from the combined Center for Astrophysics and Southern Sky redshift surveys. We find evidence for type- dependent clustering differences in the LCRS, such that galaxies brighter than about $M^{\ast }-1$ appear about 50\% more strongly clustered than those fainter, and that a sample of emission galaxies shows 30\% weaker clustering than the full LCRS sample. On large scales $\hat{I}»\gtrsim 40h^{-1}$~Mpc, we have also fit the LCRS results to various linear CDM models, and find that a number of them could meet the constraints set by the LCRS power spectrum, the Hubble constant range $0.5\lesssim h\lesssim 0.8$, the abundance of galaxy clusters, and the reasonable assumption that LCRS galaxies are roughly unbiased tracers of the mass, relative to the normalization provided by the 4-year COBE DMR data. The possibilites include open CDM or flat non-zero cosmological-constant CDM models with $\hat{I}{\text{c◯}}_0\approx 0.4-0.6$ and shape parameter $\hat{I}“\approx 0.2-0.3$, as well as flat $\hat{I}{\text{c◯}}_0=1$ models with massive neutrino density $\hat{I}{\text{c◯}}_{\hat{I}}½\approx 0.2-0.3$ or a spectral tilt $n\approx 0.7-0.8$. (abridged)

48 pages, including 15 of 16 postscript figures, uses AASTEX v4.0 style files, to appear in ApJ. The full paper is available at http://manaslu.astro.utoronto.ca/~lin/lcrs.html (North America) and http://www.aip.de:8080/~tucker/lcrs-mirror.html (Europe)