Volume 396, Number 3, December IV 2002
|Page(s)||847 - 855|
|Section||Cosmology (including clusters of galaxies)|
|Published online||05 December 2002|
A VLT/FORS2 spectroscopic survey in the HDF-S*
European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
2 Dipartimento di Astronomia dell'Università di Padova, Vicolo dell'Osservatorio 2, 35122 Padova, Italy
3 INAF – Osservatorio Astronomico di Trieste, via G.B. Tiepolo 11, 40131 Trieste, Italy
4 Space Telescope European Coordinating Facility, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
5 Institut d'Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France
6 INAF – Osservatorio Astronomico di Roma, via dell'Osservatorio 2, Monteporzio, Italy
7 INAF – Osservatorio Astronomico di Brera, via E. Bianchi 46, Merate, Italy
Corresponding author: E. Vanzella, email@example.com
Accepted: 30 September 2002
We report on low-resolution multi-object spectroscopy of 65 objects from to in the HDF-S obtained with the VLT Focal Reducer/low dispersion Spectrograph (FORS2). 18 objects belong to the HDF-S proper, i.e. the WFPC2 deep area. 15 high-redshift galaxies with (10 in the HDF-S proper) have been identified. The spectroscopic redshifts are in good agreement with the photometric ones derived from a minimization technique comparing the observed spectral energy distribution with synthetic libraries and with a new neural network (NN) approach. The dispersion with the former method is whereas the latter provides . No “catastrophic” difference is encountered. The inferred star formation rates of the individual objects range from tens to a few hundreds of yr-1 and the global star formation rate of the Universe at is estimated to be 0.15 yr-1 Mpc-3 with a statistical error of 0.04. Evidence for large-scale structure is found with two groups' redshifts observed at and and a pronounced low redshift peak around . An elliptical galaxy lensing a background object turns out to be at a redshift .
Key words: techniques: spectroscopic / galaxies: evolution / galaxies: formation / galaxies: distances and redshifts
© ESO, 2002
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