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J/A+A/520/A42     Galaxy groups in the VIMOS-VLT Deep Survey   (Cucciati+, 2010)

The VIMOS-VLT Deep Survey: the group catalogue. Cucciati O., Marinoni C., Iovino A., Bardelli S., Adami C., Mazure A., Scodeggio M., Maccagni D., Temporin S., Zucca E., De Lucia G., Blaizot J., Garilli B., Meneux B., Zamorani G., Le Fevre O., Cappi A., Guzzo L., Bottini D., Le Brun V., Tresse L., Vettolani G., Zanichelli A., Arnouts S., Bolzonella M., Charlot S., Ciliegi P., Contini T., Foucaud S., Franzetti P., Gavignaud I., Ilbert O., Lamareille F., McCracken H. J., Marano B., Merighi R., Paltani S., Pella R., Pollo A., Pozzetti L., Vergani D., Perez-Montero E. <Astron. Astrophys. 520, A42 (2010)> =2010A&A...520A..42C
ADC_Keywords: Surveys ; Clusters, galaxy ; Redshifts ; Velocity dispersion Keywords: galaxies: clusters: general - large-scale structure of Universe - galaxies: high-redshift - galaxies: evolution - galaxies: statistics Abstract: We present a homogeneous and complete catalogue of optical galaxy groups identified in the VIMOS-VLT Deep Survey (VVDS). We use mock catalogues extracted from the Millennium Simulation to study the potential systematics that might affect the overall distribution of the identified systems, and also to asses how well galaxy redshifts trace the line-of-sight velocity dispersion of the underlying mass overdensity. We train on these mock catalogues the adopted group-finding technique (the Voronoi-Delaunay Method, VDM), to recover in a robust and unbiased way the redshift and velocity dispersion distributions of groups and maximize the level of completeness (C) and purity (P) of the group catalogue. We identify 318(/144) VVDS groups with at least 2(/3) members within 0.2≤z≤1.0, globally with C=60% and P=50%. We use the group sample to study the redshift evolution of the fraction fb of blue galaxies (U-B≤1) within 0.2≤z≤1 in both groups and in the whole ensemble of galaxies irrespectively of their environment. Description: We have compiled a homogeneous catalogue of optical galaxy groups identified in the VVDS-02h field (0.7x0.7deg2) by means of the VDM algorithm, in the range 0.2≤z≤1.0. We give the coordinates (RA, DE and z) and a few properties (velocity dispersion, number of galaxy members) of the so-found groups. We also list the galaxies that belong to these groups (ID, RA, DE, z, quality of redshift measurement). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table4.dat 68 318 Location and properties of groups within 0.2≤z≤1 table5.dat 73 904 Id and location of galaxies in the groups listed in Table 4
See also: III/250 : The VIMOS VLT deep survey (VVDS-DEEP) (Le Fevre+ 2005) http://cencosw.oamp.fr : VVDS database Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
8- 10 I3 --- GrID Group ID 14 A1 --- n_GrID [*] Detection with only flag 3-4 galaxies (1) 18- 25 F8.5 deg RAdeg Right ascension in decimal degrees (J2000) (2) 30- 37 F8.5 deg DEdeg Declination in decimal degrees (J2000) (3) 44- 49 F6.4 --- z Redshift (4) 53- 54 I2 --- Ngal Number of galaxies 58- 61 I4 km/s sigma Velocity dispersion (5) 68 A1 --- HPDet [H] High purity detection (6)
Note (1): "*" indicates that the group has been detected also if using only the galaxies with the highest redshift measurement quality (flag 3 and 4, i.e. ≥95% confidence) Note (2): Median value of the the Right ascension of the galaxies in the group Note (3): Median value of the the Declination of the galaxies in the group Note (4): Median value of the the redshift of the galaxies in the group Note (5): sigma=0 means that the mean redshift measurement error in VVDS is higher than the estimated sigma (see the paper for more details) Note (6): "H" means that the group has been detected also when running the algorithm with high purity parameter set (see the paper for more details)
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
2- 10 I09 --- GalID Galaxy ID (CENCOS database) (1) 18- 25 F8.5 deg RAdeg Right ascension in decimal degrees (J2000) 31- 38 F8.5 deg DEdeg Declination in decimal degrees (J2000) 43- 48 F6.4 --- z Redshift 55- 56 I2 --- q_Zz Flag for quality redshift measurement (2) 64- 66 I3 --- GrID ID of the group to which the galaxy belongs(3) 72- 73 I2 --- Ngal Number of galaxies in the group
Note (1): The galaxy ID refers to the public VVDS release at http://cencosw.oamp.fr; see also Cat. III/250 Note (2): The flag indicates the likelihood with which the redshift of the galaxy has been estimated as follows: 1 = around 50% 2 = around 80% 3 = around 97% 4 = around 99% 9 = around 50%, only one emission line 2x = when one of the above-mentioned flags is preceded by the digit "2", it means that it is a secondary object in the slit. For more details see Le Fevre et al. (2005A&A...439..845L, Cat. III/250) Note (3): It corresponds to the group ID in the first column of table 4.
Acknowledgements: Olga Cucciati, olga.cucciati(at)oamp.fr References: Le Fevre et al., 2005A&A...439..845L, Cat. III/250
(End) Olga Cucciati [LAM, France], Patricia Vannier [CDS] 06-Aug-2010
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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