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GEMS in a Nutshell:
GEMS tile #58Simulation of a galaxy merger |
Science Questions:
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GEMS has imaged an
area of 900 square minutes of arc on the sky with the Advanced Camera
for Surveys (ACS) on-board Hubble Space telescope. This contiguous field
centred on the Chandra Deep Field South contains roughly 10000 galaxies
down to a depth of 24th magnitude in the R-band. The central part was observed
by the GOODS-project to an even fainter flux-limit, while GEMS mainly concentrates
on the outer regions, the extended Chandra Deep Field South. For those
10000 objects redshifts in the range 0.2<z<1.2 were determined in
the COMBO-17 project, by means of low-resolution spectra using 17 medium
band filters. Those spectra not only provide redshifts but also spectral
energy distributions (SEDs) from 3500 to 9250 Ångstroms. The mosaic
of 9 by 9 ACS pointings in the F606W and F850LP filters will allow us
in combination with the known redshifts to construct a rest-frame B-band
image of all target galaxies with resolutions < 0.1 arcseconds, corresponding
to < 500 parsec in the object's rest-frame. This unique data set including
SED and high resolution morphological information will let us determine
the evolution of galaxy structure over the last half of cosmic history. |