The study of the galaxy properties as
a function of redshifts is an obvious observational tool to constrain
galaxy formation and evolution models. Studying cluster early-type
galaxies up to redshift 0.6 points to
high-formation redshift and passive evolution, with internal gradients
of the stellar populations being caused by metallicity rather than
age. Once the evolution of their stellar populations is calibrated,
early-type galaxies can be used as ``standard candles'' to derive the
parameters of the Universe, providing results compatible with the
(more precise) Supernovae studies. In contrast, massive spiral
galaxies are very similar to local ones up to redshift
~ 1, while strong evolution is observed in low-mass disk
objects.
With the availability of 8 m class telescopes it has been possible to
detect (high redshift) galaxies in their formation, star-bursting
phases. Using galaxy clusters as additional ``gravitational
telescopes'', or deep photometric imaging combined with photometric
redshift preselection, it is possible to follow-up candidate
high-redshift objects spectroscopically and study their global
properties (ages and metallicities). A comparison with low-redshift
starbursts shows that the metal enrichment of high-redshift galaxies
must have happened at redshifts higher than 2.
The main aim of the Fors Deep Field (
FDF) Project is to probe the galaxy evolution up to z~5. Since
1999 photometric observations in the optical have been obtained in
broad-band UBgRI and medium-band z-filters with FORS1/2 at the VLT
telescopes. In addition, narrow-band images centered at 4850, 5300,
8100, 8150, 8230 and 8340 AA were taken to search specifically for
Lyα-galaxies at the redshift of Q 0136-260 and z ~ 5.7. The data
were complemented by J and Ks-observations in the NIR with SofI at the
ESO-NTT. Finally, the FDF was observed with the VLA at 1.6 GHz and 5
GHz. Follow-up spectroscopical observations of about 500 FDF objects
with FORS1/2 at the VLT telescopes have been carried out since 1999.
The Munich Near-IR Cluster Survey
(
MUNICS) is a wide-area,
medium-deep, photometric survey selected in the K' band. It covers an
area of roughly 1 square degree in the K' and J near-IR pass-bands
with complementary optical photometry in the B, V, R, and I bands
covering a subarea of 0.6 square degrees. The resulting object
catalogues were strictly selected in K', having a limiting magnitude
(50 % completeness) of K' approximately 19.5 mag and J
approximately 21 mag, sufficiently deep to detect passively evolving
systems up to a redshift of z <= 1.5 and luminosity of 0.5 L*. The
optical data reach a depth of roughly R approximately 23.5 mag. The
project's main scientific aims are the identification of galaxy
clusters at redshifts around unity and the selection of a large sample
of field early-type galaxies at 0 < z < 1.5 for evolutionary
studies. Further scientific goals are the examination of the nature of
extremely red objects (EROs) and the QSO environments.
The
EDISCS project (ESO Distant Cluster Survey) aims at studying the
evolution of cluster populations over more than 50 % of cosmic time by
comparing the photometric and spectroscopic properties of galaxies in
rich clusters at z~0.5 and z>0.8 with those of galaxies in well
studied nearby clusters. Our samples consist of the most luminous
objects in each redshift band in the external link Las Campanas
Cluster Survey, by far the largest area optical survey for distant
clusters so far completed.
last update:
10/2004, editor of this page: Roberto Philip Saglia
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