J/A+A/668/A162ivo://CDS.VizieR/J/A+A/668/A162doi:10.26093/cds/vizier.36680162CDSWang H.Canameras R.Caminha G.B.Suyu S.H.Yildirim A.Chirivi G.L.Christensen L.Grillo C.Schuldt S.2023-12-21T16:35:56Z2022-12-15T05:57:09ZCDS support team

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

cds-question@unistra.frgravitational-lensingredshiftedvisible-astronomyWe study the inner structure of the group-scale lens CASSOWARY 31 (CSWA 31) by adopting both strong lensing and dynamical modeling. CSWA 31 is a peculiar lens system. The brightest group galaxy (BGG) is an ultra-massive elliptical galaxy at z=0.683 with a weighted mean velocity dispersion of sigma=432+/-31km/s. It is surrounded by group members and several lensed arcs probing up to =~150kpc in projection. Our results significantly improve previous analyses of CSWA 31 thanks to the new HST imaging and MUSE integral-field spectroscopy. From the secure identification of five sets of multiple images and measurements of the spatially-resolved stellar kinematics of the BGG, we conduct a detailed analysis of the multi-scale mass distribution using various modeling approaches, both in the single and multiple lens-plane scenarios. Our best-fit mass models reproduce the positions of multiple images and provide robust reconstructions for two background galaxies at z=1.4869 and z=2.763. Despite small variations related to the different sets of input constraints, the relative contributions from the BGG and group-scale halo are remarkably consistent in our three reference models, demonstrating the self- consistency between strong lensing analyses based on image position and extended image modeling. We find that the ultra-massive BGG dominates the projected total mass profiles within 20kpc, while the group-scale halo dominates at larger radii. The total projected mass enclosed within Reff=27.2kpc is 1.10^+0.02^_-0.04_*10^13^M_{sun}_. We find that CSWA 31 is a peculiar fossil group, strongly dark-matter dominated towards the central region, and with a projected total mass profile similar to higher-mass cluster-scale halos. The total mass-density slope within the effective radius is shallower than isothermal, consistent with previous analyses of early-type galaxies in overdense environments.2022A&A...668A.162Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/668/A162CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/668/A162https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/668/A162http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/668/A162https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/668/A162https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/668/A162http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/668/A162GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/668/A162/tableb1 (Complete list of measured spectroscopic redshifts)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/668/A162/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/668/A162/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/668/A162/tableb1?GETtext/xml+votable180.050000true140.35723297744618.17151659471050.0055555555555555566/4494https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/668/A162?format=asciiOpticaldefaultJ/A+A/668/A162/tableb1Complete list of measured spectroscopic redshiftsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[354/999906] Source IDmeta.id;meta.mainintRAJ2000[140.34/140.37] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[18.16/18.18] Declination (J2000)degpos.eq.dec;meta.mainzspec[0.17/5.84] Measured spectroscopic redshifts of galaxiessrc.redshift;pos.heliocentricfloatQF[2.0/3.0] Quality flag of measured redshifts (1)meta.code.qual;src.redshiftfloat