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:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4 100 116 Photometry of 4C 23.56 field sources
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Byte-by-byte Description of file: table4
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Bytes Format Units Label Explanations
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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)
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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
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History: Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 07-Oct-1997