J/ApJS/109/367ivo://CDS.VizieR/J/ApJS/109/367doi:10.26093/cds/vizier.21090367CDSKnopp G.P.Chambers K.C.1998-08-31T17:00:04Z1998-08-31T16:59:10ZCDS support team

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

cds-question@unistra.frradio-galaxiesinfrared-photometryWe present deep infrared and optical imaging of a 1.25arcmin^2^ field centered on the giant (~0.5Mpc) high-redshift (z=2.479) ultra-steep-spectrum radio source 4C 23.56. The optical/infrared continuum morphology of the host galaxy is asymmetric, with strong color gradients and an enormous biconical emission-line nebula. The morphology of 4C 23.56 is best described by a dusty galaxy illuminated by a beam from an active galactic nucleus that is scattered into our line of sight. We determine the K' band number counts in the field to a limit of K'=22.5mag and find a marginally significant excess of objects with K'=19-21mag, compared to other K' band surveys. Spectral energy distributions (SEDs) of 117 objects in the field are constructed from aperture photometry in five bands (U', NB, V, I, and K'). From the SEDS we distinguish three subsets of objects as possible candidates for z~2.48 companions: emission-line galaxies, very red galaxies, and flat-spectrum star-forming galaxies. The field has nine candidate objects with line emission in a narrow band centered on the redshifted Ly{alpha} line, compared to an expected number of at most three foreground [O II] emitters that could mimic Ly{alpha} alpha sources. We find a high density of faint, very red objects with I-K'>4mag in the field, including two with I-K'>6mag.1997ApJS..109..367Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/109/367CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/109/367https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/109/367http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/109/367https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/109/367https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/109/367http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/109/367GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/109/367/table4 (Photometry of 4C 23.56 field sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/109/367/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/109/367/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/109/367/table4?GETtext/xml+votable180.050000true316.802208323.53555560.005555555555555556https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/109/367?format=asciiInfraredRadiodefaultJ/ApJS/109/367/table4Photometry of 4C 23.56 field sourcesl_VmagLimit flag on Vmagmeta.code.errorchare_NB? rms uncertainty on NB in AB magnitude (2)magstat.errorfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/117]+ Source sequential numbermeta.id;meta.mainintprimaryindexedRA2000Right ascension (2000)pos.eq.ra;meta.mainDE2000Declination (2000)pos.eq.dec;meta.mainl_U'magLimit flag on U'magmeta.code.errorcharU'magU' magnitude (3402{AA})magphot.mag;em.opt.Ufloate_U'mag? rms uncertainty on U'magmagstat.errorfloatnullablen_U'mag[sof] Note on U'mag (1)meta.notecharl_NBLimit flag on NBmeta.code.errorcharNBNarrow band magnitude (4229{AA}) in AB magnitude (2)magphot.mag;em.optfloatn_NB[sof] Note on NB (1)meta.notecharVmagV magnitude (5457{AA})magphot.mag;em.opt.Vfloate_Vmag? rms uncertainty on Vmagmagstat.errorfloatnullablen_Vmag[sof] Note on Vmag (1)meta.notecharl_ImagLimit flag on Imagmeta.code.errorcharImagI magnitude (8300{AA})magphot.mag;em.opt.Ifloate_Imag? rms uncertainty on Imagmagstat.errorfloatnullablen_Imag[sof] Note on Imag (1)meta.notecharl_K'magLimit flag on K'magmeta.code.errorcharK'magK' magnitude (21100{AA})magphot.mag;em.IR.Kfloate_K'mag? rms uncertainty on K'magmagstat.errorfloatnullablen_K'mag[sof] Note on K'mag (1)meta.notecharClassClassification (3)src.classchar