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J/A+A/540/A106      SDSS-DR8 groups and clusters of galaxies   (Tempel+, 2012)

Groups and clusters of galaxies in the SDSS DR8. Value-added catalogues. Tempel E., Tago E., Liivamagi L.J. <Astron. Astrophys. 540, A106 (2012)> =2012A&A...540A.106T
ADC_Keywords: Clusters, galaxy ; Galaxy catalogs ; Galaxies, photometry Keywords: catalogs - galaxies: clusters: general - galaxies: groups: general - galaxies: statistics - large-scale structure of Universe - cosmology: observations Abstract: We create a new catalogue of groups and clusters for the SDSS Data Release 8 sample. We add environmental parameters to our catalogue, together with other galaxy parameters (e.g., morphology), missing from our previous catalogues. We use a modified friends-of-friends (FoF) method with a variable linking length in the transverse and radial directions to eliminate selection effects and to find reliably as many groups as possible to track the supercluster network. We use the groups of galaxies as a basis to determine the luminosity density field. We take into account various selection effects caused by a magnitude limited sample. Our final sample contains 576493 galaxies and 77858 groups. The group catalogue is available at and from the Strasbourg Astronomical Data Center (CDS). Description: Galaxy and group/cluster catalogues based on SDSS DR8 data are presented. The tables are also available at File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file dr8gal.dat 430 576493 Galaxy parameters dr8gr.dat 236 77858 Group/cluster parameters
See also: II/306 : The SDSS Photometric Catalog, Release 8 (Adelman-McCarthy+, 2011) J/A+A/514/A102 : SDSS DR7 groups of galaxies (Tago+, 2010) J/A+A/479/927 : Group of galaxies in SDSS 5 (Tago+, 2008) Byte-by-byte Description of file: dr8gal.dat
Bytes Format Units Label Explanations
2- 7 I6 --- ID Unique identification number for galaxies 9- 14 I6 --- IDcl [1/388773] Group/cluster ID number (1) 18- 20 I3 --- Ngal [1/878] Richness of group the galaxy belongs to 22- 28 F7.5 --- z Redshift, corrected to CMB rest frame 30- 37 F8.4 Mpc Dist Co-moving distance of a galaxy (G1) 39- 46 F8.4 Mpc Dist.c Co-moving distance of the group centre (G1) 48- 57 F10.5 deg RAdeg Right ascension of galaxy (J2000) 59- 68 F10.5 deg DEdeg Declination of galaxy (J2000) 70- 79 F10.5 deg GLON Galactic longitude of galaxy 81- 90 F10.5 deg GLAT Galactic latitude of galaxy 92-101 F10.5 deg eta SDSS survey coordinate eta 103-112 F10.5 deg lambda SDSS survey coordinate lambda 114-121 F8.5 mag umag Galactic extinction corrected Petrosian u-magnitude 123-130 F8.5 mag gmag Galactic extinction corrected Petrosian g-magnitude 132-139 F8.5 mag rmag Galactic extinction corrected Petrosian r-magnitude 141-148 F8.5 mag imag Galactic extinction corrected Petrosian i-magnitude 150-157 F8.5 mag zmag Galactic extinction corrected Petrosian z-magnitude 159-167 F9.5 mag uMAG Absolute u-magnitude (G1) 169-177 F9.5 mag gMAG Absolute g-magnitude (G1) 179-187 F9.5 mag rMAG Absolute r-magnitude (G1) 189-197 F9.5 mag iMAG Absolute i-magnitude (G1) 199-207 F9.5 mag zMAG Absolute z-magnitude (G1) 209-217 F9.5 mag kcoru K-correction in u-filter 219-227 F9.5 mag kcorg K-correction in g-filter 229-237 F9.5 mag kcorr K-correction in r-filter 239-247 F9.5 mag kcori K-correction in i-filter 249-257 F9.5 mag kcorz K-correction in z-filter 259-268 F10.5 10+10Lsun Lr r-band observed luminosity (G1) 270-275 F6.3 --- W Weight factor for the galaxy 279-281 I3 --- Rank [1/878] Galaxy rank in its group 283-293 F11.5 --- Den1 ?=-999 Normalised environmental density at 1Mpc/h (G1) 295-305 F11.5 --- Den2 ?=-999 Normalised environmental density at 2Mpc/h (G1) 307-317 F11.5 --- Den4 ?=-999 Normalised environmental density at 4Mpc/h (G1) 319-329 F11.5 --- Den8 ?=-999 Normalised environmental density at 8Mpc/h (G1) 331-341 F11.5 --- Den16 ?=-999 Normalised environmental density at 16Mpc/h (G1) 343-350 F8.4 Mpc Edge Co-moving distance from the survey mask (G1) 352 I1 --- Mph [0/2] Morphology of galaxy, 1=S, 2=E (2) 354-360 F7.5 --- prE Probability of being an early type galaxy 362-381 A20 --- DR8objid Approximative SDSS DR8 photometric objID (3) 383-402 A20 --- DR8spec Approximative SDSS DR8 spectroscopic ID (3) 404-409 I6 --- IDDR7 ID number to link to our previous DR7 cat 411-417 F7.5 --- zobs Observed redshift (without CMB correction) 419-426 F8.4 Mpc Distcor Corrected co-moving distance of galaxy (G1) (in Mpc/h) 430 I1 --- fc [0/5] Number of missing neighbours (fibre collision) (G2)
Note (1): Groups with IDcl>77858 have only 1 galaxy. Note (2): Morphology code is: 0 = unclear; 1 = spiral; 2 = elliptical Note (3): IDs do not match the SDSS-DR8 ones (the 8 rightmost bits of the binary reporesentation were all set to zero, i.e. the correct SDSS-DR8 ID is a number between DR8objid and DR8objid+255).
Byte-by-byte Description of file: dr8gr.dat
Bytes Format Units Label Explanations
3- 7 I5 --- IDcl [1/77858] Group/cluster ID number 11- 13 I3 --- Ngal [2/878] Group richness 15- 21 F7.5 --- zcl Redshift to the group centre 23- 30 F8.4 Mpc Dist.c Co-moving distance to the group centre (G1) 32- 41 F10.5 deg RAdeg Right ascension of group centre (J2000) 43- 52 F10.5 deg DEdeg Declination of group centre (J2000) 54- 63 F10.5 deg GLON Galactic longitude 65- 74 F10.5 deg GLAT Galactic latitude 76- 85 F10.5 deg eta SDSS survey coordinate eta 87- 96 F10.5 deg lambda SDSS survey coordinate lambda 98-105 F8.5 Mpc Size Max linear size of the group in the sky (G1) 107-114 F8.5 Mpc Rvir Virial radius (projected harmonic mean) (G1) 116-123 F8.5 Mpc sigma Extent of the group in the sky (G1) 125-134 F10.4 km/s sigmav rms radial velocity deviation 136-145 F10.5 10+10Lsun Lrobs r-band observed luminosity (G1) 147-156 F10.5 10+10Lsun Lrtot r-band estimated total luminosity (G1) 158-163 F6.3 Mpc Dlink Co-moving linking length (G1) 165-175 F11.5 --- Den1 ?=-999 Environmental density for group at a=1Mpc/h (G1) 177-187 F11.5 --- Den2 ?=-999 Environmental density for group at a=2Mpc/h (G1) 189-199 F11.5 --- Den4 ?=-999 Environmental density for group at a=4Mpc/h (G1) 201-211 F11.5 --- Den8 ?=-999 Environmental density for group at a=8Mpc/h (G1) 213-223 F11.5 --- Den16 ?=-999 Environmental density for group at a=16Mpc/h (G1) 225-232 F8.4 Mpc Edge Minimum distance from survey mask (G1) 235-236 I2 --- fc [0/64] Number of potentially missing fibre collision galaxies (G2)
Global Notes: Note (G1): Throughout this study, the cosmology is defined with H0=100h km/s/Mpc, ΩM=0.27 and ΩΛ=0.73. * Distances are in Mpc/h * distance modulus are in mag+5log10(h) * luminosities are in L/h2 Note (G2): if greater than zero, indicates that the galaxy has a missing (with unknown redshift) neighbour due to a fibre collision.
Acknowledgements: Elmo Tempel, elmo (at) History: * 28-Feb-2012: Original version * 12-Jun-2012: warning added for the DR8objid and DR8spec columns of dr8gal (do not exactly match the DR8 objIDs)
(End) Elmo Tempel [Tartu Obs., Estonia], Patricia Vannier [CDS] 28-Feb-2012
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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