| OBSERVATIONS OF THE HAWAII HDF-N FIELD |
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| Spectroscopy of the ACS GOODS Area of the HDF-N |
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Photometric redshift surveys such as the one on the HHDF-N described in
the present website (Capak et al. 2004) can cover large areas---avoiding the
problems of cosmic variance, which can be significant in
areas the size of the ACS-GOODS region---and are useful for determining
the evolution of the luminosity function and
the universal star formation history. However,
spectroscopic redshift surveys are needed to determine
the evolution of clustering
and the environmental dependences of galaxy properties,
such as their X-ray, submillimeter, and radio emission.
Spectroscopic redshifts are also
required for determining the distribution of spectral types,
which may be combined with galaxy morphologies from
the ACS-GOODS observations, and for determining line luminosities,
which provide an alternative way of approaching the
star formation history. Finally, spectroscopic redshifts may be used
to refine photometric redshift estimates and to test what
fraction of photometric redshifts are in error
in a given field. Some classes of sources, such as broad-line AGNs
or sources that have very strong emission lines, frequently have
bad photometric redshifts (Barger et al. 2003),
and spectroscopic measurements can be used to determine how common
such sources are.
This project was funded in part by National Science Foundation grants AST-0071208, AST-0084816, and AST-0084847, and NASA grants HST-GO-09425.03-A, HST-GO-09425.30-A, DF1-2201X, and GO 2-3187B. Any opinions, findings and conclusions or recommendations expressed herein do not necessarily reflect those of the National Science Foundation or NASA. This section of the site describes our spectrocopic work on the ACS-GOODS region and also provides a table of all the published redshift information on this region. We will update this regularly thoghout the upcoming year as further data becomes available. |