J/A+A/435/781 Redshifts of galaxies in 21 EIS cluster fields (Olsen+, 2005)
Multi-object spectroscopy of low redshift EIS clusters.
III. Properties of optically selected clusters.
Olsen L.F., Benoist C., da Costa L., Hansen L., Joergensen H.E.
<Astron. Astrophys. 435, 781 (2005)>
=2005A&A...435..781O 2005A&A...435..781O
ADC_Keywords: Clusters, galaxy ; Galaxies, photometry ; Redshifts ;
Velocity dispersion
Keywords: galaxies: clusters: general - cosmology: observations -
galaxies: distances and redshifts - galaxies: photometry
Abstract:
We have carried out an investigation of the properties of
low redshift EIS clusters using both spectroscopy and imaging data.
We present new redshifts for 738 galaxies in 21 ESO Imaging Survey
(EIS) Cluster fields. We use the "gap"-technique to search for
significant overdensities in redshift space and to identify
groups/clusters of galaxies corresponding to the original EIS matched
filter cluster candidates. In this way we spectroscopically
confirm 20 of the 21 cluster candidates with a matched-filter
estimated redshift zMF=0.2. We have now obtained spectroscopic
redshifts for 34 EIS cluster candidates with zMF=0.2 (see also
Hansen et al., 2002, Cat. J/A+A/388/1; Olsen et al., 2003,
Cat. J/A+A/409/439. Of those we spectroscopically confirm 32
with redshifts ranging from z=0.064 to 0.283.
We find that: 1) the velocity dispersions of the systems range from
sigmav≤130km/s to sigmav=1200km/s, typical of galaxy groups to rich
clusters; 2) richnesses corresponding to Abell classes R≤1; and 3)
concentration indices ranging from C=0.2 to C=1.2. From the analysis
of the colours of the galaxy populations we find that 53% of the
spectroscopically confirmed systems have a "significant" red
sequence. These systems are on average richer and have higher velocity
dispersions. We find that the colour of the red sequence galaxies
matches passive stellar evolution predictions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 49 738 List of galaxy redshifts
table5.dat 94 32 Properties of the confirmed EIS clusters and groups
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See also:
J/A+A/388/1 : Redshifts of five EIS clusters (Hansen+, 2002)
J/A+A/409/439 : Redshifts of 11 EIS clusters (Olsen+, 2003)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Sequential identification number for this table
6- 7 I2 h RAh Right ascension J2000
9- 10 I2 min RAm Right ascension J2000
12- 17 F6.3 s RAs Right ascension J2000
19 A1 --- DE- Declination sign J2000
20- 21 I2 deg DEd Declination J2000
23- 24 I2 arcmin DEm Declination J2000
26- 30 F5.2 arcsec DEs Declination J2000
35- 39 F5.2 mag Imag EIS I magnitude
43- 48 F6.4 --- z Measured redshift
49 A1 --- Notes [e:] e=emission line(s) (1)
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Note (1): The note is:
e = we identified emission line(s);
: = an uncertain measurement, where no features could be identified.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Sequential identification number for this table
5- 7 A3 --- --- [EIS]
8- 18 A11 --- Name EIS cluster name (JHHMM+DDMM)
21- 22 I2 --- Memb Number of member galaxies
24- 28 F5.3 --- z Mean redshift
30- 33 I4 km/s sigma Velocity dispersion
36- 38 I3 km/s E_sigma Upper error of sigma
41- 43 I3 km/s e_sigma Lower error of sigma
46- 49 F4.1 --- Rich Lambda-richness
52- 55 F4.2 --- CI Concentration index
58- 63 F6.3 mag V-Ip ?=-9.999 V-I from photometric analysis
64 A1 --- n_V-Ip [ab] Note when no data (1)
67- 70 F4.1 % sgp ?=-9.9 Significance of detected photometric
sequence
71 A1 --- n_sgp [ab] Note when no data (1)
74- 79 F6.3 mag V-Is ?=-9.999 V-I from spectroscopic analysis
80 A1 --- n_V-Is [ab] Note when no data (1)
82- 85 F4.1 % sgs ?=-9.9 Significance of spectroscopic sequence
86 A1 --- n_sgs [ab] Note when no data (1)
88- 93 F6.3 mag Scatter ?=-9.999 Scatter of spectroscopic sequence
94 A1 --- n_Scatter [ab] Note when no data (1)
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Note (1): Note when no photometric data as follows:
a = no sequence was found
b = V-I is not available
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Acknowledgements: Lisbeth Fogh Olsen, olsen(at)obs-nice.fr
(End) Lisbeth Fogh Olsen [Obs. Nice], Patricia Vannier [CDS] 22-Feb-2005