The scaling of the redshift power spectrum: observations from the Las Campanas redshift survey

In a recent paper we have studied the redshift power spectrum P-S(k, mu) in three cold dark matter (CDM) models with the help of high-resolution simulations. Here we apply the method to the largest available redshift survey, the Las Campanas Redshift Survey (LCRS). The basic model is to express P-S(k, mu) as a product of three factors P-S(k, mu) = P-R(k)X(1 + beta mu (2))D-2(k, mu). Here mu is the cosine of the angle between the wave vector and the line of sight. The damping function D for the range of scales accessible for an accurate analysis of the LCRS is well approximated by the Lorentz factor D = [I + 1/2(k mu sigma (12))(2)](-1). We have investigated different values for beta (i.e. beta = 0.4, 0.5, 0.6), and measured the real-space power spectrum P-R(k) and the pairwise velocity dispersion sigma (12)(k) from P-S(k, mu) for different values of mu. The velocity dispersion sigma (12)(k) is nearly a constant from k = 0.5-3 h Mpc(-1). The average value for this range is 510 +/- 70 km s(-1). The power spectrum PR (k) decreases with k approximately, with k(-1.7) for k between 0.1 and 4 h Mpc(-1). The statistical significance of the results, and the error bars, are found with the help of mock samples constructed from a large set of high-resolution simulations. A flat, low-density (Ohm (0) = 0.2) CDM model can give a good fit to the data, if a scale-dependent special bias scheme is used which we have called the cluster-underweighted bias (Jing, Mo & Borner).