THE POWER SPECTRA OF IRAS GALAXIES AND OF ABELL CLUSTERS

This work measures the power spectra of IRAS galaxies and of Abell clusters by analyzing the 2 Jy IRAS redshift survey and two redshift samples of Abell clusters. In terms of the variance DELTA2(k), we find that the DELTA2(k) of IRAS galaxies obeys a power law DELTA2(k) is-proportional-to k1.3 up to the largest possible wavelength lambda = 2pi/k approximately 100 h-1 Mpc which the survey is able to explore. The DELTA2(k) of Abell clusters has the same slope as that of IRAS galaxies for lambda < 100 h-1 Mpc but has an amplitude about 10 times higher, which supports the ''linear'' biasing mechanism as the origin of rich clusters. At larger wavelengths, the variance of Abell clusters falls more rapidly than the power law. Under the ''linear'' biasing assumption, the DELTA2(k) of IRAS galaxies is well expressed by DELTA2(k) = (k/0.3)1.3/[1 + (k/0.025)-2.7], where k is in h Mpc-1. The fitting formula is taken to be scale-invariant at large wavelengths, which is supported by the recent COBE DMR observation as well as inflation theories. Assuming a biasing factor of 1.5 for IRAS galaxies, we find the Sachs-Wolfe effect with the above variance can correctly produce the temperature quadrupole Q = 6 x 10(-6) observed in the COBE