J/ApJS/130/237 LCRS loose groups of galaxies (Tucker+, 2000)
Loose groups of galaxies in the Las Campanas Redshift Survey.
Tucker D.L., Oemler A.Jr, Hashimoto Y., Shectman S.A., Kirshner R.P.,
Lin H., Landy S.D., Schechter P.L., Allam S.S.
<Astrophys. J. Suppl. Ser. 130, 237 (2000)>
=2000ApJS..130..237T 2000ApJS..130..237T
ADC_Keywords: Clusters, galaxy ; Galaxy catalogs ; Redshifts
Keywords: catalogs - galaxies: clusters: general -
galaxies: distances and redshifts -
large-scale structure of universe - surveys
Abstract:
A "friends-of-friends" percolation algorithm has been used to extract
a catalog of δn/n=80 density enhancements (groups) from the six
slices of the Las Campanas Redshift Survey (LCRS). The full catalog
contains 1495 groups and includes 35% of the LCRS galaxy sample. A
clean sample of 394 groups has been derived by culling groups from the
full sample that either are too close to a slice edge, have a crossing
time greater than a Hubble time, have a corrected velocity dispersion
of zero, or contain a 55"-'orphan' (a galaxy with a mock redshift that
was excluded from the original LCRS redshift catalog due to its
proximity to another galaxy, i.e., within 55").
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 183 1495 LCRS Groups Catalogue
table3.dat 76 7621 LCRS Group Members
table7.dat 93 54 LCRS Group-Abell Cluster Matches
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See also:
VII/203 : Las Campanas Redshift Survey (LCRS) (Shectman+ 1996)
VII/4 : Abell and Zwicky Clusters of Galaxies (Abell+ 1974)
J/AJ/119/2598 : LCRS galaxies u'g'r'i'z' photometry (Sowards-Emmerd+, 2000)
J/ApJS/123/41 : LCRS radio galaxies (Machalski+, 1999)
J/ApJS/137/117 : Las Campanas Distant Cluster Survey, LCDCS (Gonzales+, 2001)
J/MNRAS/327/588 : Las Campanas/AAT Rich Cluster Survey (Pimbblet+, 2001)
J/AN/321/101 : Compact groups of galaxies in LCRS (Allam+, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- SubG [a-f] Group subdivision (G1)
4- 6 I3 --- Group Group identification
7 A1 --- f_Group [*] Flag indicates group is a member of the
clean sample
9- 10 I2 h RAh Group barycenter Right Ascension (B1950)
12- 13 I2 min RAm Group barycenter Right Ascension (B1950)
15- 19 F5.2 s RAs Group barycenter Right Ascension (B1950)
21 A1 --- DE- Group barycenter Declination (1950)
22- 23 I2 deg DEd Group barycenter Declination (1950)
25- 26 I2 arcmin DEm Group barycenter Declination (1950)
28- 31 F4.1 arcsec DEs Group barycenter Declination (1950)
34- 39 F6.4 --- z Group redshift (1)
44- 48 F5.1 km/s LOS Group line-of-sight velocity dispersion
52- 56 F5.1 km/s e_LOS Formal standard error in LOS
60- 61 I2 --- NLCRS Observed number of LCRS galaxies comprising
the group (2)
64- 67 F4.2 Mpc RadP The mean pairwise separation, in Mpc/h (3)
70- 73 F4.2 Mpc e_RadP Estimated rms error in RadP, in Mpc/h (3)
76- 79 F4.2 Mpc RadH The harmonic radius, in Mpc/h (3)
82- 85 F4.2 Mpc e_RadH Estimated rms error in RadH, in Mpc/h (3)
88- 91 F4.2 --- CTime The crossing time as a fraction of the Hubble
time (H0), in H0-1
94- 97 F4.2 --- e_CTime The estimated rms error CTime as a fraction of
the Hubble time (H0), in H0-1
100-107 E8.2 solMass MVir Group's virial mass, in solMass/h (3)
110-117 E8.2 solMass e_MVir The estimated rms error in MVir,
in solMass/h (3)
120-127 E8.2 solLum RLum Total group LCRS R-band luminosity,
in solLum/h2 (3)
130-137 E8.2 solLum e_RLum The estimated rms error RLum, solLum/h2 (3)
139-144 F6.2 --- LRat Ratio by which the sum of the luminosities of
NLCRS must be multiplied to obtain an estimate
of the RLum.
147-152 F6.1 Sun M/L Group mass-to-light ratio in LCRS R-band,
in h.solMass/solLum (3)
153-159 F7.1 Sun e_M/L The estimated rms error in M/L,
in h.solMass/solLum (3)
162-164 I3 --- CAbell Group's Abell counts estimate (4)
169-172 F4.1 --- e_CAbell Estimated rms error in CAbell (5)
176-177 I2 --- GType The type of group (6)
180-182 A3 --- RNotes Applicable table notes (7)
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Note (1): Corrected for motion relative to the Cosmic Microwave Background.
Note (2): Including any 55-arcsec-"orphans".
Note (3): Where H0 = h*100 km/s/Mpc.
Note (4): Note that, for Abell clusters in the LCRS, we find that
CAbell = 0.19 C(ACO) + 12, where C(ACO) is the value for the Abell
counts from Abell, Corwin, and Olowin (Cat. VII/4).
Note (5): Based upoPoisson statistics of the observed number of LCRS member
galaxies within a projected distance of 1.5 Mpc/h of the group center.
Note (6):
3 = group is within the borders of a 50-fiber field.
4 = group is within the borders of a 112-fiber field.
5 = group straddles the border of a 50-fiber and a 112-fiber field.
Note (7):
a = The group's crossing time is greater than a Hubble time.
b = The group's barycenter is closer than 2RadP to a slice edge.
c = The group contains at least one 55-arcsec "orphan" with a
faked velocity.
d = The group's line-of-sight velocity dispersion, corrected for galaxy
velocity errors, is less than or equal to 0 km/s.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1 A1 --- SubG [a-f] Group subdivision (G1)
3- 5 I3 --- Group Group identification number
10- 15 F6.4 --- z Group redshift
19- 24 F6.1 km/s LOS Group line-of-sight velocity dispersion
27- 28 I2 --- MemID Group member identification number
31- 32 I2 h RAh Right Ascension (B1950)
34- 35 I2 min RAm Right Ascension (B1950)
37- 41 F5.2 s RAs Right Ascension (B1950)
43 A1 --- DE- Declination (1950)
44- 45 I2 deg DEd Declination (1950)
47- 48 I2 arcmin DEm Declination (1950)
50- 53 F4.1 arcsec DEs Declination (1950)
55- 59 F5.2 mag Rmag Isophotal R-band magnitude
61- 65 F5.2 mag Cenmag The 2-pixel-radius central magnitude (1)
68- 72 I5 km/s HVel Heliocentric velocity
75 A1 --- Type Type of spectrum (2)
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Note (1): Used in star/galaxy separation and in excluding very low surface
brightness objects from the spectroscopic survey.
Note (2): Type of spectrum:
e: strong emission lines
c: continuum with absorption lines
b: both absorption lines and moderate emission lines
m: mock velocity -- galaxy was one of the 55arcsec "orphans" excluded
from the spectroscopic survey due to its proximity to another galaxy
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1 A1 --- SubG [a-f] Table1 subdivision (G1)
3- 5 I3 --- Group Group number
6 A1 --- n_Group [a] Note on Group (1)
8- 9 I2 h RAh Group right ascension (1950.0)
11- 12 I2 min RAm Group right ascension (1950.0)
14- 18 F5.2 s RAs Group right ascension (1950.0)
20 A1 --- DE- Group declination sign (1950.0)
21- 22 I2 deg DEd Group declination (1950.0)
24- 25 I2 arcmin DEm Group declination (1950.0)
27- 30 F4.1 arcsec DEs Group declination (1950.0)
32- 37 F6.4 --- z Group redshift
39- 40 I2 --- Nobs Observed number of galaxies from the LCRS official
spectroscopic sample that lie within the group
42- 44 I3 ---- Cgrp Estimate of the group Abell richness
46- 49 F4.1 --- e_Cgrp rms uncertainty on Cgrp
51- 55 A5 --- Abell Name of the Abell cluster match to the group
57- 58 I2 h RAAh Abell cluster's right ascension (1950.0)
60- 63 F4.1 min RAAm Abell cluster's right ascension (1950.0)
65 A1 --- DEA- Abell cluster's declination sign (1950.0)
66- 67 I2 deg DEAd Abell cluster's declination (1950.0)
69- 70 I2 arcmin DEAm Abell cluster's declination (1950.0)
72- 78 F7.5 --- zA ? Abell cluster's redshift
79 A1 --- r_zA Reference for Abell cluster's redshift (2)
81 I1 --- RA ? Abell cluster's richness class
83 I1 --- DA ? Abell cluster's distance class
85- 87 I3 ---- CA Abell cluster's Abell counts, as measured by ACO
89- 93 F5.2 arcmin Sep Angular separation between the measured group
center and the Abell cluster center as reported
by ACO (3)
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Note (1): a: Includes as a member at least one 55"-orphan with a faked velocity.
Note (2): Redshift references:
b: Abell et al., 1989, Cat. VII/110
c: Ebeling et al., 1996MNRAS.281..799E 1996MNRAS.281..799E;
obtained from the NASA/IPAC Extragalactic Database (NED).
d: Olowin, De Souza, & Chincarini, 1988A&AS...73..125O 1988A&AS...73..125O;
obtained from the NASA/IPAC Extragalactic Database (NED).
e: Ebeling & Maddox, 1995MNRAS.275.1155E 1995MNRAS.275.1155E;
obtained from the NASA/IPAC Extragalactic Database (NED).
f: Dalton et al., 1994, Cat. J/MNRAS/269/151;
obtained from the NASA/IPAC Extragalactic Database (NED).
g: Collins et al., 1995, Cat. J/MNRAS/274/1071;
obtained from the NASA/IPAC Extragalactic Database (NED).
h: Stocke et al., 1991, Cat. IX/15;
obtained from the NASA/IPAC Extragalactic Database (NED).
Note (3): A group-cluster pair was considered a "match" if this angular
separation was less than 12' (∼1h-1*Mpc at the median redshift of
the LCRS).
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Global notes:
Note (G1): Subdividions as follows:
a: LCRS -03° Group, LCLG -03 NNN in Simbad
b: LCRS -06° Group, LCLG -06 NNN in Simbad
c: LCRS -12° Group, LCLG -12 NNN in Simbad
d: LCRS -39° Group, LCLG -39 NNN in Simbad
e: LCRS -42° Group, LCLG -42 NNN in Simbad
f: LCRS -45° Group, LCLG -45 NNN in Simbad
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History:
From ApJS electronic version
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 15-Jan-2001