J/A+A/479/927 Group of galaxies in SDSS 5 (Tago+, 2008)
Groups of galaxies in the SDSS Data Release 5. A group-finder and a catalogue.
Tago E., Einasto J., Saar E., Tempel E., Einasto M., Vennik J., Muelle V.
<Astron. Astrophys. 479, 927 (2008)>
=2008A&A...479..927T 2008A&A...479..927T
ADC_Keywords: Galaxy catalogs ; Clusters, galaxy ; Galaxies, photometry
Keywords: cosmology: observations - galaxies: clusters: general -
cosmology: large-scale structure of the Universe -
Abstract:
We extract groups of galaxies from the SDSS Data Release 5 to study
the supercluster-void network and environmental properties of groups
therein. Groups of galaxies as density enhancements can be used to
determine the luminosity density field of the supercluster-void
network.
We use a modified friends-of-friends (FoF) method with slightly
variable linking lengths in transverse and radial directions to
eliminate selection effects and to reliably find as many groups as
possible. To determine the scaling of the linking length we calibrated
group sizes and mean galaxy number densities within groups by shifting
nearby groups to larger distances.
Our final sample contains 17143 groups in the equatorial (E), and
33219 groups in the northern (N) part of the DR5 survey. The mean
sizes and velocity dispersions of our groups practically do not change
with their distance. This means that the selection effects have been
properly taken into account when generating the group catalogue.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3a.dat 109 17143 Sample E groups (dr5Egr)
table3b.dat 109 33219 Sample N groups (dr5Ngr)
table3c.dat 155 129985 Sample E galaxies (dr5Egal)
table3d.dat 155 257078 Sample N galaxies (dr5Ngal)
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See also:
J/AN/327/365 : Clusters and groups of galaxies in 2dF (Tago+, 2006)
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file: table3a.dat table3b.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Group Group identification number
7- 9 I3 --- Ngal Richness (number of member galaxies)
11- 22 F12.8 deg RAdeg Right Ascension in decimal degrees, J2000
(mean of member galaxies)
24- 34 F11.8 deg DEdeg Declination in decimal degrees, J2000
(mean of member galaxies)
36- 43 F8.4 Mpc Dist Comoving distance (mean of member galaxies
corrected for CMB), in Mpc/h
45- 50 F6.4 Mpc Size Maximum projected linear size, in Mpc/h
52- 61 F10.6 km/s sigma rms radial velocity (velocity dispersion)
63- 70 F8.6 Mpc Rvir Virial radius (projected harmonic mean),
in Mpc/h
72- 83 E12.7 10+10solLum Lmain Luminosity of main galaxy (1)
85- 96 E12.7 10+10solLum LgrObs Observed total group luminosity (1)
98-109 E12.7 10+10solLum LgrEst Estimated total group luminosity (1)
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Note (1): In units of 1010L☉/h2.
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Byte-by-byte Description of file: table3c.dat table3d.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Group Group identification number
7- 9 I3 --- Ngal Group richness
11- 16 I6 --- Galaxy Galaxy identification number
18- 23 F6.2 Mpc Dist Co-moving distance corrected for CMB
25- 31 F7.2 Mpc SX Supergalactic X coordinate, in Mpc/h
33- 39 F7.2 Mpc SY Supergalactic Y coordinate, in Mpc/h
41- 46 F6.2 Mpc SZ Supergalactic Z coordinate, in Mpc/h
48- 57 F10.6 deg RAdeg Right ascension in decimal degrees, J2000.0
59- 67 F9.6 deg DEdeg Declination in decimal degrees, J2000.0
69- 78 F10.6 deg lambda SDSS lambda coordinate
80- 89 F10.6 deg eta SDSS eta coordinate
91- 96 F6.3 mag umag SDSS u magnitude
98-103 F6.3 mag gmag g magnitude
105-110 F6.3 mag rmag r magnitude
112-117 F6.3 mag imag i magnitude
119-124 F6.3 mag zmag z magnitude
126-134 F9.6 mag Kcorr K correction (+ evol) in r band
136-142 F7.3 mag rMAG Absolute magnitude in r band
144-155 E12.7 10+10solLum L(r) Luminosity in r band
(in units of 1010L☉/h2)
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Acknowledgements:
Erik Tago, erik(at)aai.ee
(End) Patricia Vannier [CDS] 20-Dec-2007