J/ApJ/805/181ivo://CDS.VizieR/J/ApJ/805/181doi:10.26093/cds/vizier.18050181CDSCibinel A.Le Floc'h E.Perret V.Bournaud F.Daddi E.Pannella M.,Elbaz D.Amram P.Duc P.-A.2017-10-16T10:45:38Z2015-10-20T14:38:35ZCDS support team

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

cds-question@unistra.frgalaxiesphotometryredshiftedgalaxy-classification-systemsAt z>~1, the distinction between merging and "normal" star-forming galaxies based on single band morphology is often hampered by the presence of large clumps which result in a disturbed, merger-like appearance even in rotationally supported disks. In this paper we discuss how a classification based on canonical, non-parametric structural indices measured on resolved stellar mass maps, rather than on single-band images, reduces the misclassification of clumpy but not merging galaxies. We calibrate the mass-based selection of mergers using the MIRAGE hydrodynamical numerical simulations of isolated and merging galaxies which span a stellar mass range of 10^9.8^-10^10.6^M_{sun}_ and merger ratios between 1:1-1:6.3. These simulations are processed to reproduce the typical depth and spatial resolution of observed Hubble Ultra Deep Field (HUDF) data. We test our approach on a sample of real z~=2 galaxies with kinematic classification into disks or mergers and on ~100 galaxies in the HUDF field with photometric/spectroscopic redshift between 1.5<=z<=3 and M>10^9.4^M_{sun}_. We find that a combination of the asymmetry A_MASS_ and M_20,MASS_ indices measured on the stellar mass maps can efficiently identify real (major) mergers with <~20% contamination from clumpy disks in the merger sample. This mass-based classification cannot be reproduced in star-forming galaxies by H-band measurements alone, which instead result in a contamination from clumpy galaxies which can be as high as 50%. Moreover, we find that the mass-based classification always results in a lower contamination from clumpy galaxies than an H-band classification, regardless of the depth of the imaging used (e.g., CANDELS versus HUDF).2015ApJ...805..181Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/805/181CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/261 : GOODS initial results (Giavalisco+, 2004)J/AJ/148/137 : Merging galaxies in COSMOS to z~1 (Lackner+, 2014)J/ApJ/780/34 : H_160_-selected cat. of galaxies in the HUDF (Lundgren+, 2014)J/ApJ/776/71 : ZENS: gal. in groups along the cosmic web. I. (Carollo+, 2013)J/ApJS/207/24 : GOODS-S CANDELS multiwavelength catalog (Guo+, 2013)J/ApJ/768/74 : PHIBSS: CO obs. of star-forming galaxies (Tacconi+, 2013)J/A+A/539/A91 : MASSIV I. Sample properties (Contini+, 2012)J/ApJS/203/24 : Structural param. of galaxies in CANDELS (van der Wel+, 2012)J/ApJ/743/146 : HST/WFC3 observations in HUDF and GOODS-S (Cameron+, 2011)J/ApJ/735/86 : NEWFIRM MBS: photometric catalogs (Whitaker+, 2011)J/ApJ/735/L22 : HUDF galaxy properties at z~2 (Szomoru+, 2011)J/ApJ/706/1364 : SINS survey of high-redshift gal. (Forster Schreiber+, 2009)J/AJ/132/1729 : Hubble Ultra Deep Field BVI-dropout sources (Beckwith+, 2006)J/AJ/132/926 : Galaxies in the Hubble Ultra Deep Field (Coe+, 2006)J/AJ/128/163 : Galaxy morphological classification (Lotz+, 2004)J/ApJS/147/1 : Classification of nearby galaxies (Conselice+, 2003)J/ApJ/588/218 : i*g* photometry of SDSS EDR galaxies (Abraham+, 2003)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/805/181https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/805/181http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/805/181https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/805/181https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/805/181http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/805/181GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/805/181/table1 (Classification of HUDF galaxies)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/805/181/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/805/181/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/805/181/table1?GETtext/xml+votable180.050000true53.16764-27.830370.0055555555555555566/35935https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/805/181?format=asciiOpticaldefaultJ/ApJ/805/181/table1Classification of HUDF galaxiesClassClassification (3)src.classcharf_z[s] Indicates z is a spectroscopic redshiftmeta.codecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[8740/17172] CANDELS number of the galaxy (1)meta.id;meta.mainintf_ID[*] *: strong contamination from neighboring objectsmeta.codecharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainz[1.4/3] Photometric redshiftsrc.redshiftfloatM20MASS[-2.3/-0.6] The M20 mass index from the mass map (2)stat.fit.paramfloate_M20MASS[0.01/0.3] Uncertainty in M20MASSstat.errorfloatAMASS[0.01/0.6] Asymmetry index from the mass map (2)stat.fit.paramfloate_AMASS[0.005/0.2] Uncertainty in AMASSstat.errorfloatPhotPhotometric data used for mass map generation (4)meta.bibcharSimbadSimbad column added by the CDSmeta.ref.urlchar