This paper examines the implications of a nonzero cosmological constant
Λ 0 on the amount of linear
size evolution and the luminosity selection effects usually required in the
interpretation of the angular diameter–redshift
(θ–z) test. This is based on three typical
cases chosen on various plausible assumptions which can be made concerning the
contribution of Λ 0 to the
density of the universe (parametrised by
?0). The results show that a
fairly strong linear size evolution will be required to interpret the
θ–z data of extended steep spectrum quasars
for all three cases, if luminosity effects are neglected. However, this
evolution is significantly steeper in a matter-dominated universe with
?M =
?0 = 1 than in both
the flat universe with ?Λ
= 0·8, ?M
= 0·2 and an open universe with
?M = 0·2,
Λ = 0.
Furthermore, when the luminosity selection effects present in the sample are
considered, a milder size evolution is obtained for the
?M = 1,
?Λ = 0 model while
little or no size evolution is found for the other two cases. There is
therefore no significant difference in our results for an open low density
universe with ?Λ =
0 and a flat universe dominated by
?Λ predicted by
inflation. The present results therefore imply that an open low density
universe with ?M =
0·2 and ?Λ
= 0 is compatible with an inflationary model of the universe with
?M = 0·2 and
?Λ = 0 · 8.
This leads to a contradiction since the universe cannot be open and spatially
closed at the same time (the existence of one should preclude the other).
SNe Ia Redshift in a Nonadiabatic Universe