J/AJ/123/3018 Redshifts of radio-selected poor clusters (Miller+, 2002)
Redshifts for a sample of radio-selected poor clusters.
Miller N.A., Ledlow M.J., Owen F.N., Hill J.M.
<Astron. J. 123, 3018 (2002)>
=2002AJ....123.3018M 2002AJ....123.3018M
ADC_Keywords: Clusters, galaxy ; Radio sources ; Redshifts
Keywords: galaxies: active - galaxies: clusters: general -
galaxies: distances and redshifts
Abstract:
Multifiber optical spectroscopy has been performed on galaxies in the
vicinity of strong, nearby radio galaxies. These radio galaxies were
selected from the 3CR and B2 catalogs based on their exclusion from
the Abell catalog, which is puzzling given the hypothesis that an
external medium is required to confine the radio plasma of such
galaxies. Velocities derived from the spectra were used to confirm the
existence of groups and poor clusters in the fields of most of the
radio galaxies. We find that all radio galaxies with classical
Fanaroff-Riley type I morphologies prove to reside in clusters,
whereas the other radio galaxies often appear to be recent
galaxy-galaxy mergers in regions of low galaxy density. These findings
confirm the earlier result that the existence of extended X-ray
emission combined with a statistical excess of neighboring galaxies
can be used to identify poor clusters associated with radio galaxies.
Description:
The complete sample is composed of 25 radio galaxies drawn from the
3CRR (Laing, Riley, & Longair, 1983MNRAS.204..151L 1983MNRAS.204..151L) and Wall & Peacock
(1985, Cat. J/MNRAS/216/173) catalogs, plus 24 additional radio
galaxies drawn from the B2 catalog (Colla et al., 1970 & 1972, Cat.
VIII/36). The B2 sources are generally of lower radio luminosity but
were added because the declination range of that survey made them
excellent targets for observation at Kitt Peak. The radio galaxies
were required to be nearby (z<0.06 for the 3CRR and Wall & Peacock
galaxies, z<0.04 for the B2 galaxies) and not members of Abell
clusters. We report on a subset of 25 of these radio galaxies in this
paper. The remainder were unobservable because of declination limits
of the telescope (six sources) and observing time lost because of
weather. The full sample of radio galaxies and comments on their
properties may be found in Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 93 49 3C and B2 non-Abell cluster radio galaxies
refs.dat 69 13 References
table2.dat 116 369 3C/B2 cluster member velocities
table3.dat 117 95 Foreground and background galaxy velocities
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See also:
VIII/36 : The Second Bologna Survey (Colla+ 1970-1974)
J/MNRAS/216/173 : Bright extragalactic radio sources at 2.7 GHz (Wall+, 1985)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Source Radio galaxy name
17- 18 I2 h RAh Right ascension (J2000.0)
20- 21 I2 min RAm Right ascension (J2000.0)
23- 24 I2 s RAs Right ascension (J2000.0)
26 A1 --- DE- Declination sign (J2000.0)
27- 28 I2 deg DEd Declination (J2000.0)
30- 31 I2 arcmin DEm Declination (J2000.0)
33- 34 I2 arcsec DEs Declination (J2000.0)
37- 41 F5.3 --- z Redshift
43- 45 A3 --- Obs [Yes No] Indicates whether spectroscopic
observations of the radio galaxy field are
included in this paper
46 A1 --- n_Obs [ab] Note on Obs (1)
49- 85 A37 --- Com Radio morphology and brief comments
88- 93 A6 --- Refs References for the radio morphology,
in refs.dat file
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Note (1): Notes as follows:
a = Below declination limit of telescope
b = Above declination limit of telescope
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference code
4- 22 A19 --- BibCode BibCode
24- 48 A25 --- Aut Author's name
50- 69 A20 --- Com Comments
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Byte-by-byte Description of file: table2.dat table3.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Source Radio galaxy name (G1) (1)
14- 15 I2 h RAh Galaxy right ascension (J2000.0) (G1)
17- 18 I2 min RAm Galaxy right ascension (J2000.0) (G1)
20- 23 F4.1 s RAs Galaxy right ascension (J2000.0) (G1)
25 A1 --- DE- Galaxy declination sign (J2000.0) (G1)
26- 27 I2 deg DEd Galaxy declination (J2000.0) (G1)
29- 30 I2 arcmin DEm Galaxy declination (J2000.0) (G1)
32- 33 I2 arcsec DEs Galaxy declination (J2000.0) (G1)
36- 40 I5 km/s cz ? This study heliocentric velocity from
cross-correlation of emission lines
42- 44 I3 km/s e_cz ? rms uncertainty on cz
45 A1 --- n_cz [c] Note on cz (2)
47- 51 I5 km/s cz2 ? Prior studies heliocentric velocity,
as reported in NED
53- 55 I3 km/s e_cz2 ? rms uncertainty on cz2
56 A1 --- n_cz2 [a] a: Velocity data from Ledlow et al.,
1996AJ....112..388L 1996AJ....112..388L
58-117 A60 --- EmLines Emission lines present (3)
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Note (1): In original table2, 1651+351 was misprint for 1615+351.
Note (2): Member of an identified cluster from the ROSAT All-Sky Survey,
RX J1652.6+4011 (Boehringer et al., 2000, Cat. J/ApJS/129/435).
The cluster is also in the Abell catalog, as Abell 2235.
Note (3): If in parentheses, the reported velocity is based on
cross-correlation of the absorption lines.
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Global notes:
Note (G1): Identification of galaxies in Simbad:
In table 2, [MLO2002] B2 HHMM+DD JHHMMSS.s+DDMMSS or
[MLO2002] 3C NNN JHHMMSS.s+DDMMSS
In table 3, [MLO2002] JHHMMSS.s+DDMMSS
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History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 24-Apr-2003