Volume 512, March-April 2010
|Number of page(s)||22|
|Section||Cosmology (including clusters of galaxies)|
|Published online||23 March 2010|
VLT/VIMOS spectroscopy in the GOODS-south field: Part II
European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany e-mail: email@example.com
2 Max-Planck-Institut fur extraterrestrische Physik, Giessenbachstrasse 2, 85748 Garching, Germany
3 National Optical Astronomy Observatory, PO Box 26732, Tucson, AZ 85726, USA
4 INAF – Osservatorio Astronomico di Trieste, via G.B. Tiepolo 11, 40131 Trieste, Italy
5 Institute for Advanced Studies in Basic Sciences, PO Box 45159-1159, Zanjan 45159, Iran
6 Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
Accepted: 21 December 2009
Context. We present the full data set of the VIsible Multi-Object Spectrograph (VIMOS) spectroscopic campaign of the ESO/GOODS program in the Chandra Deep Field South (CDFS), which complements the FORS2 ESO/GOODS spectroscopic campaign.
Aims. The ESO/GOODS spectroscopic programs are aimed at reaching signal-to-noise ratios adequate to measure redshifts for galaxies with AB magnitudes in the range ~24-25 in the B and R band using VIMOS, and in the z band using FORS2.
Methods. The GOODS/VIMOS spectroscopic campaign is structured in two separate surveys using two different VIMOS grisms. The VIMOS Low Resolution Blue (LR-Blue) and Medium Resolution (MR) orange grisms have been used to cover different redshift ranges. The LR-Blue campaign is aimed at observing galaxies mainly at 1.8 < z < 3.5, while the MR campaign mainly aims at galaxies at z < 1 and Lyman Break Galaxies (LBGs) at z > 3.5.
Results. The full GOODS/VIMOS spectroscopic campaign consists of 20 VIMOS masks. This release adds 8 new masks to the previous release (12 masks, Popesso et al. 2009, A&A, 494, 443). In total we obtained 5052 spectra, 3634 from the 10 LR-Blue masks and 1418 from the 10 MR masks. A significant fraction of the extracted spectra comes from serendipitously observed sources: ~21% in the LR-Blue and ~16% in the MR masks. We obtained 2242 redshifts in the LR-Blue campaign and 976 in the MR campaign for a total success rate of 62% and 69% respectively, which increases to 66% and 73% if only primary targets are considered. The typical redshift uncertainty is estimated to be 0.00084 (~255 km s-1) for the LR-Blue grism and 0.00040 (~120 km s-1) for the MR grism. By complementing our VIMOS spectroscopic catalog with all existing spectroscopic redshifts publicly available in the CDFS, we compiled a redshift master catalog with 7332 entries, which we used to investigate large scale structures out to z 3.7. We produced stacked spectra of LBGs in a few bins of equivalent width (EW) of the Ly-α and found evidence for a lack of bright LBGs with high EW of the Ly-α. Finally, we obtained new redshifts for 12 X-ray sources of the CDFS and extended-CDFS.
Conclusions. After the completion of the two complementary ESO/GOODS spectroscopic campaigns with VIMOS and FORS2 at VLT, the number of spectroscopic redshifts in CDFS/GOODS field increased dramatically, in particular at z 2. These data provide the redshift information indispensable to achieve the scientific goals of GOODS, such as tracing the evolution of galaxy masses, morphologies, clustering, and star formation.
Key words: large scale structure of Universe / catalogs / surveys / galaxies: evolution / galaxies: high-redshift / cosmology: observations
Based on observations made at the European Southern Observatory, Paranal, Chile (ESO program 171.A-3045 The Great Observatories Origins Deep Survey: ESO Public Observations of the SIRTF Legacy/HST Treasury/Chandra Deep Field South.)
Catalogs and data products are available in electronic form at http://archive.eso.org/cms/eso-data/data-packages
Appendices are only available in electronic form at http://www.aanda.org
© ESO, 2010
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