J/ApJ/453/48ivo://CDS.VizieR/J/ApJ/453/48doi:10.26093/cds/vizier.14530048CDSDriver S.P.Windhorst R.A.Griffiths R.E.1997-12-09T19:55:33Z1997-12-09T20:55:30ZCDS support team

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

cds-question@unistra.frgalaxiesphotometrygalaxy-classification-systemsWe present a complete morphologically classified sample of 144 faint field galaxies from the HST Medium Deep Survey with 20.0=<Imag<22.0mag. We compare the global properties of the ellipticals and early- and late-type spirals and find a non-negligible fraction (13/144) of compact blue [(V-I)<1.0mag] systems with r^1/4^ profiles. We give the differential galaxy number counts for ellipticals and early-type spirals independently and find that the data are consistent with no-evolution predictions based on conventional flat Schechter luminosity functions (LFs) and a standard cosmology. Conversely, late-type/irregulars show a steeply rising differential number count with slope ({delta}logN/{delta}m)=0.64+/-0.1. No-evolution models based on the Loveday et al. (1992ApJ...390..338L) and Marzke et al. (1994AJ....108..437M & 1994ApJ...428...43M) local luminosity functions underpredict the late-type/irregular counts by 1.0 and 0.5dex, respectively, at Imag=21.75mag. Examination of the irregulars alone shows that ~50% appear inert and the remainder have multiple cores. If the inert galaxies represent a non-evolving late-type population, then a Loveday-like LF ({alpha}=~-1.0) is ruled out for these types, and an LF with a steep faint end ({alpha}=~-1.5) is suggested. If multiple core structure indicates recent star formation, then the observed excess of faint blue field galaxies is likely a result of et evolutionary processes acting on a steep field LF for late-type/irregulars. The evolutionary mechanism is unclear, but 60% of the multiple-core irregulars show close companions. To reconcile a Marzke-like LF with the faint redshift surveys, this evolution must be preferentially occurring in the brightest late-type galaxies with z>=0.5 at m_I_=21.75mag.1995ApJ...453...48Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/453/48CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/112/359 : Galaxies in the Hubble Deep Field (van den Bergh+ 1996)J/AJ/112/1335 : Hubble Deep Field observations (Williams+ 1996)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/453/48https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/453/48http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/453/48https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/453/48https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/453/48http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/453/48GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/453/48/table2 (A complete catalog of HST field galaxies obtained from the six MDS fields)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/453/48/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/453/48/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/453/48/table2?GETtext/xml+votable180.050000true13.35787512.54477780.005555555555555556HSThttps://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/453/48?format=asciiOpticaldefaultJ/ApJ/453/48/table2A complete catalog of HST field galaxies obtained from the six MDS fieldsMDSMDS field namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDObject identification numbermeta.idintWFPC2WFPC2 CCD number (1=PC, 2, 3, 4=WFC)meta.idintXposOriginal X pixel position on the WFPC2 CCDpixpos.cartesian.x;instr.detfloatYposOriginal Y pixel position on the WFPC2 CCDpixpos.cartesian.y;instr.detfloatRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination signpos.eq.dec;meta.mainnullableImagTotal I_814_ magnitudemagphot.mag;em.opt.IfloatV-ITotal (V-I) colormagphot.color;em.opt.V;em.opt.IfloatSuBrCentral I-band surface brightness within a radius of 0.2"mag.arcsec**-2phot.mag.sb;em.opt.Ifloat(V-I)cCentral (V-I) color within a radius of 0.2"magphot.color;em.opt.V;em.opt.IfloatepsImage ellipticity e=1-a/b, computed from the outermost isophotesrc.ellipticityfloatMtypeGalaxy type (2)src.morph.typeintRadiusAperture radius used to determine the I-band magnitudepixinstr.setupint