J/ApJS/109/367      4C 23.56 field deep imaging (Knopp+ 1997)

Deep imaging of the field of the high-redshift radio source 4C 23.56 Knopp G.P., Chambers K.C. <Astrophys. J. Suppl. Ser. 109, 367 (1997)> =1997ApJS..109..367K 1997ApJS..109..367K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Photometry, infrared Keywords: galaxies: individual (4C 23.56) - galaxies: photometry - galaxies: structure - infrared: galaxies - radio continuum: galaxies Abstract: We present deep infrared and optical imaging of a 1.25arcmin2 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 Lyα line, compared to an expected number of at most three foreground [O II] emitters that could mimic Lyα 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. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table4 100 116 Photometry of 4C 23.56 field sources -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4 -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- Seq [1/117]+ Source sequential number 5- 6 I2 h RAh Right ascension (J2000) 8- 9 I2 min RAm Right ascension (J2000) 11- 15 F5.2 s RAs Right ascension (J2000) 18- 19 I2 deg DEd Declination (J2000) 21- 22 I2 arcmin DEm Declination (J2000) 24- 27 F4.1 arcsec DEs Declination (J2000) 29 A1 --- l_U'mag Limit flag on U'mag 30- 34 F5.2 mag U'mag U' magnitude (3402Å) 36- 39 F4.2 mag e_U'mag ? rms uncertainty on U'mag 41 A1 --- n_U'mag [sof] Note on U'mag (1) 43 A1 --- l_NB Limit flag on NB 44- 48 F5.2 mag NB Narrow band magnitude (4229Å) in AB magnitude (2) 50- 53 F4.2 mag e_NB ? rms uncertainty on NB in AB magnitude (2) 55 A1 --- n_NB [sof] Note on NB (1) 57 A1 --- l_Vmag Limit flag on Vmag 58- 62 F5.2 mag Vmag V magnitude (5457Å) 64- 67 F4.2 mag e_Vmag ? rms uncertainty on Vmag 69 A1 --- n_Vmag [sof] Note on Vmag (1) 71 A1 --- l_Imag Limit flag on Imag 72- 76 F5.2 mag Imag I magnitude (8300Å) 78- 81 F4.2 mag e_Imag ? rms uncertainty on Imag 83 A1 --- n_Imag [sof] Note on Imag (1) 85 A1 --- l_K'mag Limit flag on K'mag 86- 90 F5.2 mag K'mag K' magnitude (21100Å) 92- 95 F4.2 mag e_K'mag ? rms uncertainty on K'mag 97 A1 --- n_K'mag [sof] Note on K'mag (1) 99-100 A2 --- Class Classification (3) -------------------------------------------------------------------------------- Note (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 Note (2): In the AB-magnitude system, any object with a flat spectrum (F_ν prop. to ν0) has the same magnitude, independent of passband: mAB=-2.5log(fν) - 48.59 Note (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 -------------------------------------------------------------------------------- History: Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 07-Oct-1997
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