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 similar to 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: similar to 21% in the LR-Blue and similar to 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 sigma(z) similar or equal to 0.00084 (similar to 255 km s(-1)) for the LR-Blue grism and sigma(z) similar or equal to 0.00040 (similar to 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 similar or equal to 3.7. We produced stacked spectra of LBGs in a few bins of equivalent width (EW) of the Ly-alpha and found evidence for a lack of bright LBGs with high EW of the Ly-alpha. 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 greater than or similar to 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.
The Great Observatories Origins Deep Survey VLT/VIMOS spectroscopy in the GOODS-south field: Part II
ROSATI, Piero;
2010
Abstract
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 similar to 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: similar to 21% in the LR-Blue and similar to 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 sigma(z) similar or equal to 0.00084 (similar to 255 km s(-1)) for the LR-Blue grism and sigma(z) similar or equal to 0.00040 (similar to 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 similar or equal to 3.7. We produced stacked spectra of LBGs in a few bins of equivalent width (EW) of the Ly-alpha and found evidence for a lack of bright LBGs with high EW of the Ly-alpha. 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 greater than or similar to 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.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
