Open AccessA comparison of the PSCz and Stromlo–APM redshift surveys
Author(s) -
Seaborne M. D.,
Sutherland W.,
Tadros H.,
Efstathiou G.,
Frenk C. S.,
Keeble O.,
Maddox S.,
McMahon R. G.,
Oliver S.,
RowanRobinson M.,
Saunders W.,
White S. D. M.
Publication year - 1999
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1999.02796.x
Subject(s) - physics , astrophysics , redshift , galaxy , redshift survey , correlation function (quantum field theory) , flux (metallurgy) , astronomy , materials science , optoelectronics , dielectric , metallurgy
We present a direct comparison of the clustering properties of two redshift surveys covering a common volume of space: the recently completed IRAS Point Source Catalogue redshift survey (PSCz) containing 14 500 galaxies with a limiting flux of 0.6 Jy at 60 μm, and the optical Stromlo–APM survey containing 1787 galaxies in a region of 4300 deg 2 in the south Galactic cap. We use three methods to compare the clustering properties: the counts‐in‐cells comparison of Efstathiou, the two‐point cross‐correlation function, and the Tegmark ‘null‐buster’ test. We find that the Stromlo variances are systematically higher than those of PSCz, as expected owing to the deficit of early‐type galaxies in IRAS samples. However, we find that the differences between the cell counts are consistent with a linear bias between the two surveys, with a relative bias parameter b rel ≡ b Stromlo b PSCz ≈1.3, which appears approximately scale‐independent. The correlation coefficient R between optical and IRAS densities on scales ∼20 h −1 Mpc is R 0.72 at 95 per cent confidence limit, placing limits on types of ‘stochastic bias’ that affect optical and IRAS galaxies differently.