J/ApJ/685/235ivo://CDS.VizieR/J/ApJ/685/235doi:10.26093/cds/vizier.16850235CDSPatton D.R.Atfield J.E.2017-11-29T11:48:47Z2010-12-22T15:22:39ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frgalaxiesvisible-astronomysloan-photometryredshiftedspectroscopyWe measure the number of companions per galaxy (N_c_) as a function of r-band absolute magnitude for both the Sloan Digital Sky Survey (DR5) and the Croton and coworkers semianalytic catalog, 2006MNRAS.365...11C, applied to the Millennium Run simulation (Springel et al., 2005Natur.435..629S). For close pairs with projected separations of 5-20kpc/h, velocity differences less than 500km/s, and luminosity ratios between 1:2 and 2:1, we find good agreement between the observations and simulations, with N_c_ consistently close to 0.02 over the range -22<M_r_<-18. For larger pair separations, N_c_(M_r_) instead becomes increasingly steep toward the faint end, implying that luminosity-dependent clustering plays an important role on small scales. Using the simulations to assess and correct for projection effects, we infer that the real-space N_c_(M_r_) for close pairs peaks at about M^*^ and declines by at least a factor of 2 as M_r_ becomes fainter. Conversely, by measuring the number density of close companions, we estimate that at least 90% of all major mergers occur between galaxies which are fainter than L^*^. Finally, measurements of the luminosity density of close companions indicate that L^*^ galaxies likely dominate in terms of the overall importance of major mergers in the evolution of galaxy populations at low redshift.2008ApJ...685..235Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/685/235CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)J/MNRAS/388/1537 : Galaxy pairs from SDSS-DR2 (McIntosh+, 2008)J/AJ/134/2385 : Occulting galaxy pairs in SDSS (Holwerda+, 2007)J/AJ/127/1883 : Merging galaxies in SDSS EDR (Allam+, 2004)http://www.sdss.org/ : SDSS home pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/685/235https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/685/235http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/685/235https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/685/235https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/685/235http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/685/235GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/685/235/table1 (SDSS host galaxies with companions)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/685/235/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/685/235/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/685/235/table1?GETtext/xml+votable180.050000true10.603723114.70510390.0055555555555555566/0 4096 4098 4119 4182 4188 4602 4738 4745 4747 4751 4758 4797 4799 4837 4906 4920 4947 4957 4961 4973 4982 4999 5015 5017 5040 5052 5061 5064 5066 5078 5095 5099 5116 5278 5308 5338 5346 5350 5364 5365 5413 5421 5449 5468 5470 5475 5482 5498 5515 5521 5536 5537 5560 5564 5579 5598 5618 5628 5647 5659 5689 5692 5696 5773 5774 5824 5855 5876 5930 5967 5972 5974 5975 5979 5981 5982 5988 5989 5990 6000 6001 6002 6004 6007 6026 6031 6032 6080 6096 6106 6109 6118 6134 6226 6367 6527 6532 6545 6557 6559 6577 7221 7223 7248 7257 7269 7305 7307 7315 7360 7361 7432 7456 8201 8208 8227 8671 9050 9073 9084 9086 9150 9172 9194 9232 9237 9240 9246 9252 9261 9292 9321 9332 9339 9354 9378 9468 9471 9473 9482 9504 9507 9730 9733 9750 9764 9891 9902 9915 10094 10098 10217 10539 10552 10563 10606 10643 10673 10716 10729 10733 10795 10812 10814 10847 10862 10902 10911 10976 11006 11007 11058 11072 11084 11087 11101 11135 11138 11150 11179 11193 11229 11243 11336 11343 11409 11420 11438 11447 11476 11591 11777 11784 11801 11813 12289 17293 17315 17750 18381 18618 18857 18859 19092 19095 19100 19113 19416 19749 22005 23183 23202 23204 25841 25852 25909 25914 25931 25952 25959 25982 26033 26059 26074 26080 26141 26142 26174 26193 26197 26198 26271 26304 26305 26318 26329 26948 26956 26984 26990 27052 27053 27058 27082 27104 27228 27247 27259 27333 27334 27337 27344 27381 27392 27397 27408 27411 27416 27427 27436 27462 27539 27586 27620 27648 27691 27693 27709 27764 27770 27772 27853 27860 27869 27881 27925 28162 28613 28619 28639 28649 28654 28655 31394 31397 31415 32429 32482 32492https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/685/235?format=asciiOpticaldefaultJ/ApJ/685/235/table1SDSS host galaxies with companionsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRSimbad column added by the CDSmeta.notecharHostHost object identification (SDSS ObjId) (1)meta.id.parentcharRAdegHost right ascension in decimal degrees (J2000)degpos.eq.raDEdegHost declination in decimal degrees (J2000)degpos.eq.decdoublezRedshiftsrc.redshiftdoublerMAGAbsolute SDSS r band magnitude (2)magphys.magAbs;em.opt.RfloatCompCompanion object identification (SDSS ObjId) (1)meta.id;meta.maincharrDistance to the host objectarcsecpos.angDistancefloatnullableDR7Display SDSS-DR7 photometric data of Host and Companionmeta.ref.urlcharSloanDisplay the SDSS data for this galaxymeta.ref.urlchar_RAPosition of companion object (from SDSS-DR7, Cat. II/294) (right ascension part)degpos.eq.ra;meta.main_DEPosition of companion object (from SDSS-DR7, Cat. II/294) (declination part)degpos.eq.dec;meta.main