The power spectrum of the Point Source Catalogue redshift survey

We measure the redshift-space power spectrum P(k) for the recently completed IRAS Point Source Catalogue (PSC) redshift survey, which contains 14 500 galaxies over 84 per cent of the sky with 60-mu m flux greater than or equal to 0.6 Jy. Comparison with simulations shows that our estimated errors on P(k) are realistic, and that systematic errors resulting from the finite survey volume are small for wavenumbers k greater than or similar to 0.03 h Mpc(-1). At large scales our power spectrum is intermediate between those of the earlier QDOT and 1.2-Jy surveys, but with considerably smaller error bars; it falls slightly more steeply to smaller scales. We have fitted families of CDM-like models using the Peacock-Dodds formula for non-linear evolution; the results are somewhat sensitive to the assumed small-scale velocity dispersion sigma(v). Assuming a realistic sigma(v) = 300 km s(-1) yields a shape parameter Gamma similar to 0.25 and normalization b sigma(8) similar to 0.75; if sigma(v) is as high as 600 km s(-1) then Gamma = 0.5 is only marginally excluded. There is little evidence for any 'preferred scale' in the power spectrum or non-Gaussian behaviour in the distribution of large-scale power.