J/ApJ/741/122ivo://CDS.VizieR/J/ApJ/741/122doi:10.26093/cds/vizier.17410122CDSOwers M.S.Nulsen P.E.J.Couch W.J.2017-07-10T13:23:55Z2017-07-10T14:16:53ZCDS support team

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

cds-question@unistra.frredshiftedgalaxiesspectroscopygalaxy-clustersWe present evidence for the existence of substructure in the "relaxed appearing" cold front clusters Abell 2142 and RXJ1720.1+2638. The detection of these substructures was made possible by comprehensive multi-object optical spectroscopy obtained with the Hectospec and DEep Imaging Multi-Object Spectrograph instruments on the 6.5m MMT and 10m Keck II telescope, respectively. These observations produced 956 and 400 spectroscopically confirmed cluster members within a projected radius of 3Mpc from the centers of A2142 and RXJ1720.1+2638, respectively. The substructure manifests itself as local peaks in the spatial distribution of member galaxies and also as regions of localized velocity substructure. For both Abell 2142 and RXJ1720.1+2638, we identify group-scale substructures which, when considering the morphology of the cold fronts and the time since pericentric passage of a perturber estimated from the cold front radii, could plausibly have perturbed the cluster cores and generated the cold fronts observed in Chandra images. The results presented here are consistent with cold fronts being the result of merger activity and with cold fronts in relaxed appearing clusters being due to minor merger activity.2011ApJ...741..122Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/741/122CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)VII/193 : The CfA Redshift Catalogue, Version June 1995 (Huchra+ 1995)VII/165 : Measured Redshifts of Abell Clusters of Galaxies (Andernach 1991)VII/177 : Redshifts & Velocity Dispersions for Abell Clusters (Struble+ 1991)VIII/43 : Radio survey of clusters of galaxies (Andernach+ 1978)J/MNRAS/416/2840 : The 2M++ galaxy redshift catalogue (Lavaux+, 2011)J/ApJ/384/404 : Redshifts of rich clusters of galaxies (Postman+ 1992)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/741/122https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/741/122http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/741/122https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/741/122https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/741/122http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/741/122GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/741/122/zcat (Spectroscopic redshifts in A2142 and RX J1720.1+2638)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/741/122/zcat?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/741/122/zcat?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/741/122/zcat?GETtext/xml+votable180.050000true239.0364530627.235901110.0055555555555555566/8671 9354 9376 32500https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/741/122?format=asciiOpticaldefaultJ/ApJ/741/122/zcatSpectroscopic redshifts in A2142 and RX J1720.1+2638recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClmeta.id;meta.datasetcharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.maincz[2639/1162416] Spectroscopic redshiftkm/ssrc.redshift;pos.heliocentricdoublee_cz[3/1009] Uncertainty in czkm/sstat.errorfloatInstInstrument for cz (Keck/DEIMOS, MMT/Hectospec, SDSS)instr.setupcharSDSSCross-match with SDSS-DR7 catalog within 1.5"meta.ref.urlintnullable