J/ApJS/109/367 J/ApJS/109/367 4C 23.56 field deep imaging G P Knopp K C Chambers Astrophys. J. Suppl. Ser. 109 367 1997 1997ApJS..109..367K Galaxies, radio Photometry, infrared galaxies: individual (4C 23.56) galaxies: photometry galaxies: structure infrared: galaxies radio continuum: galaxies We 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.

Seq Source sequential number --- RAh Right ascension (2000) h RAm Right ascension (2000) min RAs Right ascension (2000) s DEd Declination (2000) deg DEm Declination (2000) arcmin DEs Declination (2000) arcsec l_U'mag Limit flag on U'mag --- U'mag U' magnitude (3402{AA}) mag e_U'mag rms uncertainty on U'mag mag n_U'mag Note on U'mag number=1 We abbreviate the notes to waveband measurements as s = saturated o = obscured in the wings of a bright source and thus not identified f = failed to meet selection criteria --- l_NB Limit flag on NB --- NB Narrow band magnitude (4229{AA}) in AB magnitude number=2 In the AB-magnitude system, any object with a flat spectrum (F_{nu} prop. to {nu}^0^) has the same magnitude, independent of passband: m_AB_=-2.5log(f_{nu}_) - 48.59 mag e_NB rms uncertainty on NB in AB magnitude number=2 In the AB-magnitude system, any object with a flat spectrum (F_{nu} prop. to {nu}^0^) has the same magnitude, independent of passband: m_AB_=-2.5log(f_{nu}_) - 48.59 mag n_NB Note on NB number=1 We abbreviate the notes to waveband measurements as s = saturated o = obscured in the wings of a bright source and thus not identified f = failed to meet selection criteria --- l_Vmag Limit flag on Vmag --- Vmag V magnitude (5457{AA}) mag e_Vmag rms uncertainty on Vmag mag n_Vmag Note on Vmag number=1 We abbreviate the notes to waveband measurements as s = saturated o = obscured in the wings of a bright source and thus not identified f = failed to meet selection criteria --- l_Imag Limit flag on Imag --- Imag I magnitude (8300{AA}) mag e_Imag rms uncertainty on Imag mag n_Imag Note on Imag number=1 We abbreviate the notes to waveband measurements as s = saturated o = obscured in the wings of a bright source and thus not identified f = failed to meet selection criteria --- l_K'mag Limit flag on K'mag --- K'mag K' magnitude (21100{AA}) mag e_K'mag rms uncertainty on K'mag mag n_K'mag Note on K'mag number=1 We abbreviate the notes to waveband measurements as s = saturated o = obscured in the wings of a bright source and thus not identified f = failed to meet selection criteria --- Class Classification number=3 Our tentative object classifications are abbreviated as follows: FS = field star UG = unidentified galaxy E = elliptical S = spiral Im = irregular RG = 4C 23.56 --- James Marcout, Patricia Bauer CDS 1997Oct07 UNKNOWN UNKNOWN Prepared via OCR at CDS. J_ApJS_109_367.xml