J/A+A/609/A78ivo://CDS.VizieR/J/A+A/609/A78doi:10.26093/cds/vizier.36090078CDSBarbosa C.E.Arnaboldi A.Coccato L.Gerhard O.Mendes de Oliveira C.,Hilker M.Richtler T.2018-03-12T08:40:08Z2018-01-11T08:17:01ZCDS support team

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

cds-question@unistra.frgalaxiesvisible-astronomyEarly-type galaxies (ETGs) show a strong size evolution with redshift. This evolution is explained by fast "in-situ" star formation at high-z followed by a late mass assembly mostly driven by minor mergers that deposit stars primarily in the outer halo. Aims: We aim to identify the main structural components of the Hydra I cD galaxy NGC 3311 to investigate the connection between the central galaxy and the surrounding stellar halo. We produce maps of the line-of-sight velocity distribution (LOSVD) moments from a mosaic of MUSE pointings covering NGC 3311 out to 25kpc. Combining deep photometric and spectroscopic data, we model the LOSVD maps using a finite mixture distribution, including four non-concentric components that are nearly isothermal spheroids, with different line-of-sight systemic velocities V, velocity dispersions sigma, and small (constant) values of the higher order Gauss-Hermite moments h_3_ and h_4_. The kinemetry analysis indicates that NGC 3311 is classified as a slow rotator, although the galaxy shows a line-of-sight velocity gradient along the photometric major axis. The comparison of the correlations between h_3_ and h_4_ with V{sigma} with simulated galaxies indicates that NGC 3311 assembled mainly through dry mergers. The sigma profile rises to approximately 400$ km/s at 20kpc, a significant fraction (0.55) of the Hydra I cluster velocity dispersion, indicating that stars there were stripped from progenitors orbiting in the cluster core. The finite mixture distribution modeling supports three inner components related to the central galaxy and a fourth component with large effective radius (51kpc) and velocity dispersion (327km/s) consistent with a cD envelope. We find that the cD envelope is offset from the center of NGC 3311 both spatially (8.6kpc) and in velocity ({delta}V=204km/s), but coincides with the cluster core X-ray isophotes and the mean velocity of core galaxies. Also, the envelope contributes to the broad wings of the LOSVD measured by large h_4 values within 10 kpc. The cD envelope of NGC 3311 is dynamically associated with the cluster core, which in Hydra I is in addition displaced from the cluster center, presumably due to a recent subcluster merger.2018A&A...609A..78Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/609/A78CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/589/A139 : Stellar populations of NGC 3311 (Barbosa+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/609/A78https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/609/A78http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/609/A78https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/609/A78https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/609/A78http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/609/A78GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/609/A78/list (List of fits datacubes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/609/A78/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/609/A78/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/609/A78/list?GETtext/xml+votable180.050000true159.1785-27.529350.0055555555555555566/38853https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/609/A78?format=asciiOpticaldefaultJ/A+A/609/A78/listList of fits datacubesNxNumber of pixels along X-axismeta.numberintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainscaleScale of the imagearcsec/pixinstr.scalefloatNyNumber of pixels along Y-axismeta.numberintNzNumber of slicesmeta.numberintObs.dateObservation date (YYYY-MM-DDThh:mm:ss.ss)time.epoch;obscharblambdaLower value of wavelength interval0.1nmem.wlfloatBlambdaUpper value of wavelength interval0.1nmem.wlfloatdlambdaWavelength resolution0.1nmspect.resolutionfloatsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar