J/A+A/446/97 NEP Distant Cluster Radio Galaxies (Branchesi+, 2006)
The radio luminosity function of the NEP distant cluster radio galaxies.
Branchesi M., Gioia I.M., Fanti C., Fanti R., Perley R.
<Astron. Astrophys. 446, 97 (2006)>
=2006A&A...446...97B 2006A&A...446...97B
ADC_Keywords: Clusters, galaxy ; Galaxies, radio ; Redshifts ; Morphology
Keywords: galaxies: clusters: general - galaxies: high-redshift -
galaxies: evolution - radio continuum: galaxies -
cosmology: observations - X-rays: galaxies: clusters
Abstract:
A complete sample of 18 X-ray selected clusters of galaxies belonging
to the ROSAT North Ecliptic Pole (NEP) survey has been observed with
the Very Large Array at 1.4GHz in B configuration. These are the most
distant clusters in the X-ray survey with redshift in the range
0.3<z<0.8. Seventy-nine radio sources are detected within half an Abell
radius with an observed peak brightness ≥0.17mJy/beam, except for
three sources, belonging to the same cluster, which have a higher peak
brightness limit of 0.26mJy/beam. The NEP field source counts are in
good agreement with the source counts of a comparison survey, the
VLA-VIRMOS deep field survey, indicating that the NEP sample is
statistically complete. Thirty-two out of the 79 sources are within
0.2 Abell radii, twenty-two of them are considered cluster members
based on spectroscopic redshifts or their optical magnitude and
morphological classification. The cluster radio galaxies are used to
construct the Radio Luminosity Function (RLF) of distant X-ray
selected clusters. A comparison with two nearby cluster RLFs shows
that the NEP RLF lies above the local ones, has a steeper slope at low
radio powers (≤1024W/Hz) and shows no evidence for a break at
about 6x1024W/Hz which is observed in the nearby cluster RLFs. We
discuss briefly the origin and possible explanations of the
differences observed in the radio properties of nearby and distant
clusters of galaxies. The main result of this study is that the RLF of
the distant X-ray clusters is very different from that of the local
rich Abell clusters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 92 79 The Radio Source Catalogue
table3.dat 63 44 Optical counterparts of the radio sources
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See also:
J/A+AS/134/221 : Radio-loud ROSAT sources near NEP (Brinkmann+, 1999)
J/ApJS/93/145 : Radio survey around North Ecliptic Pole (Kollgaard+, 1994)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [NEP]
5- 8 I4 --- NEP Cluster designation, NEP NNNN
10- 14 F5.3 mJy rms Average image noise within half an Abell
radius in mJy/beam
16 A1 --- Src [A-M] Source designation
17 A1 --- OC [*] indicates an optical counterpart in table3
18- 19 I2 h RAh Right ascension (J2000) (1)
21- 22 I2 min RAm Right ascension (J2000) (1)
24- 28 F5.2 s RAs Right ascension (J2000) (1)
30 A1 --- DE- Declination sign (J2000) (1)
31- 32 I2 deg DEd Declination (J2000) (1)
34- 35 I2 arcmin DEm Declination (J2000) (1)
37- 40 F4.1 arcsec DEs Declination (J2000) (1)
43- 46 F4.2 --- Dist Distance from the cluster center in units
of Abell radius
48- 52 F5.2 mJy Sp Bandwidth smearing corrected peak brightness
54- 57 F4.2 mJy e_Sp rms uncertainty on Sp
59- 64 F6.2 mJy SI Integrated flux density (2)
66- 69 F4.2 mJy e_SI rms uncertainty on SI
71- 75 F5.2 arcsec ThetaM ? Beam deconvolved angular sizes for resolved
sources (3)
76 A1 --- --- [x]
77- 81 F5.2 arcsec Thetam ? Beam deconvolved angular sizes for resolved
sources (3)
83- 88 F6.2 deg PA ? Source major axis position angle,
measured from North through East
90- 92 A3 --- Notes Notes relative to the radio morphology (4)
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Note (1): For sources with a multiple structure the coordinates refer to
the radio centroid while for all the others, including complex
morphology sources, the coordinates refer to the position of the
radio peak. Exception is source NEP 2420 D where the radio position
refers to the midpoint between the two brightest peaks.
Note (2): For sources too extended for a multi-gaussian fit the integrated flux
density comes from the AIPS task TVSTAT
Note (3): For multi-component sources the source total size is listed.
For clearly extended sources the size was measured directly on the
radio images from the lowest reliable contour. Details on the source
structure are given in Section 6.1 of the paper.
Note (4): Notes relative to the radio morphology based on the criteria
given at the beginning of Section 4 of the paper. For sources reliably
fitted b y a Gaussian model the following letters are used:
u = unresolved,
ru = partially resolved,
r = resolved,
Multi-component sources or sources too extended for a Gaussian fit
are indicated by "ext".
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [NEP]
5- 8 I4 --- NEP Cluster designation, NEP NNNN
10 A1 --- Src [A-M] Source identification letter
12- 13 I2 h RAh Right ascension (J2000) (1)
15- 16 I2 min RAm Right ascension (J2000) (1)
18- 22 F5.2 s RAs Right ascension (J2000) (1)
24 A1 --- DE- Declination sign (J2000) (1)
25- 26 I2 deg DEd Declination (J2000) (1)
28- 29 I2 arcmin DEm Declination (J2000) (1)
31- 34 F4.1 arcsec DEs Declination (J2000) (1)
36- 39 F4.1 arcsec ORA Offset in right ascension, between optical
and radio coordinates
41- 44 F4.1 arcsec ODE Offset in declination, between optical
and radio coordinates
46- 49 F4.1 mag Rmag ?=- POSS apparent red (R) magnitude
51- 54 F4.1 mag Bmag ?=- POSS apparent red (BJ) magnitude
56 A1 --- S/G [SG] Optical classification Star/Galaxy (2)
58- 62 F5.3 --- z ? Spectroscopically measured redshift.
Typical uncertainty is ≤0.001
63 A1 --- Memb [*] *: radio source is a cluster member
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Note (1): Coordinates of the optical counterpart (J2000), from the
on-line SuperCOSMOS/POSS II red catalogue. The APM/POSS I catalogue
was used for NEP 3130. Exceptions are the coordinates for sources A,
B and C in NEP 5281, which were derived from the I-band image taken
at the UH 2.2m telescope.
Note (2): Optical classification according to SuperCosmos/POSS II
(APM/POSS I catalogue for NEP 3130) as follows:
G = galaxy
S = star-like
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Acknowledgements:
Marica Branchesi, mbranch(at)ira.cnr.it
(End) Patricia Vannier [CDS] 20-Sep-2005