322 Highlights in modern observational cosmology
Large area surveys
- APM (Automatic Plate-measuring Machine, e.g. Maddoxet al1990)—
imaging photographic plates; - CfA survey (Center for Astrophysics, e.g. Huchraet al1990);
LCRS (Las Campanas Redshift Survey, e.g. Shectmanet al1996)—∼ 104
galaxy redshifts, over 700 deg^2 out toz 0 .2; - 2dF survey (2 degree field, e.g. Colless 1999)—∼ 105 redshifts covering
1700 deg^2 ;and - SDSS survey (Sloan Digital Sky Survey: http://www.sdss.org)—∼—∼) 106
redshifts+multicolour imaging (10^4 deg^2 ,mlim22).
The first three surveys have provided the power spectrum of the large-scale
structure, by measuring the correlation function over a wide range of scales (see
L Guzzo, this volume), and the luminosity functions of different galaxy types in
the local universe. The on-going 2dF and SDSS surveys will soon bring these
measurements to an unprecedented level of precision.
Deep, small area surveys
- The LDSS autofib survey (Elliset al1996)—B-band selected redshift survey
down toB24 (z. 0 .7). - The CFRS survey (Lillyet al1995)—I-band selected redshift survey down
toI22 (∼600 galaxies atz.1). - The Keck Survey (Cowieet al1996)—150 galaxy redshifts out toz 1. 5
(22. 5 <B<24). - The CNOC2 surveys (Yeeet al2000)—6000 galaxy redshifts over 1.5 deg^2
area (z. 0 .6).
These surveys have established a clear evolutionary pattern for different galaxy
types out toz∼1 (see section 11.3.3).
Ultra-deep, tiny area surveys
- Hubble Deep Field North and South (e.g. Williamset al1996, Fergusonet
al2000)—5 arcmin^2 ,mlim29 (see later).
11.3.2 Survey strategies and selection methods
When planning an imaging survey (not necessarily in optical or near-IR
wavelengths which are the primary subject here), the balance between thedepth
and thesolid angle, as well as the selection of theobserved bandplay a central
role. These decisions are driven by the nature of the sources under study, as
well as their typical volume density and luminosity, i.e.φ∗andL∗(see (11.21)).
Rare objects, such as quasars or galaxy clusters, require large-area surveys to be
found in sizeable numbers. Large surveys also probe the bright end of the LF