A VLA Survey of Rich Clusters of Galaxies III. The Weaker Sources: Maps and Identifications

1996 ◽  
Vol 49 (5) ◽  
pp. 977 ◽  
Author(s):  
OB Slee ◽  
AL Roy ◽  
H Andernach
Keyword(s):  
Source Parameters ◽  
Angular Size ◽  
Optical Parameters ◽  
Clusters Of Galaxies ◽  
Very Large Array ◽  
Contour Maps ◽  
Optical Images ◽  
Extended Sources ◽  
Abell Cluster ◽  
Right Ascension

We present radio and optical parameters for 737 weak sources in 60 Abell cluster fields observed with the Very Large Array (VLA) using scaled arrays at 1.5 and 4.9 GHz. The measurements extend to a lower 1.5 GHz limit of 1.0 mJy and comprise a complete sample with 1.5 GHz flux density 2.5 ≤ S1.5 −3 sr, and the cluster fields are distributed over 24 h of right ascension and between declinations +35° and −30°. Contour maps of the extended sources at 1.5 GHz are presented and source parameters such as position, angular size and spectral index are tabulated. We also derive the emitted power and linear size for those sources with published redshifts. We try to identify the radio sources with optical images on the Palomar and SERC survey plates and give their accurate optical positions, morphologies and apparent magnitudes.

scholarly journals A VLA Survey of Rich Clusters of Galaxies II. The Stronger Sources: Maps, Polarisations and Identifications

1994 ◽  
Vol 47 (2) ◽  
pp. 145 ◽  
Author(s):  
OB Slee ◽  
AL Roy ◽  
Ann Savage
Keyword(s):  
Flux Density ◽  
Source Parameters ◽  
Angular Size ◽  
Optical Parameters ◽  
Radio Sources ◽  
Very Large Array ◽  
Contour Maps ◽  
Optical Images ◽  
5 Ghz ◽  
Linear Polarisation

We present detailed radio and optical parameters for the stronger radio sources in 58 Abell cluster fields observed with the Very Large Array (VLA) using scaled arrays at 1�5 and 4�9 GHz. These sources comprise a complete sample with 1� 5 GHz flux density :;::20 mJy and cover a combined sky area of 3�5 X 10-5 sr. The cluster fields were distributed over 24 h of RA and between declinations +350 and -300 Contour maps at two frequencies are presented and source parameters such as position, angular size, spectral index, linear polarisation and core flux density are tabulated. We also derive the emitted power and linear size for those sources close to the cluster centres and therefore highly likely to be cluster members. We attempt to identify all these radio sources with optical images on the Palomar and SERC survey plates and give their accurate optical coordinates, morphologies and apparent magnitudes.

80 MHz Survey of Extra-Galactic X-ray Sources

1979 ◽  
Vol 3 (5) ◽  
pp. 332-341 ◽  
Author(s):  
O. B. Slee ◽  
P. J. Quinn
Keyword(s):  
Angular Size ◽  
Virgo Cluster ◽  
Relativistic Electrons ◽  
Clusters Of Galaxies ◽  
Coma Cluster ◽  
Microwave Background ◽  
Significant Information ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Bremsstrahlung Emission

The completion of the Uhuru (Forman et al. 1978) and Ariel V (Cooke et al. 1978) surveys of the sky for X-ray emission has resulted in many proposed identifications with individual galaxies and clusters of galaxies. The X-ray positions are not usually accurate enough to enable a positive identification to be made of the X-ray sources with optical or radio objects, and hence the identification is often based on statistical arguments — viz., the unexpected occurrence of unusual galaxies, radio sources or clusters of galaxies within or near the X-ray error boxes. There is usually no significant information available on the angular size of the X-ray emitter but in two or three cases (e.g. Perseus cluster, Coma cluster and Virgo cluster) the angular resolution is good enough to identify a broad component with dimensions approaching those of the whole cluster. This extended X-ray emission has been ascribed to either inverse Compton scattering of the 3° microwave background by relativistic electrons in the intra-cluster medium or to thermal-bremsstrahlung emission by an optically thin plasma at - 10s K.

scholarly journals Catalogue of Clusters that are Members of Superclusters

1983 ◽  
Vol 104 ◽  
pp. 185-186
Author(s):  
M. Kalinkov ◽  
K. Stavrev ◽  
I. Kuneva
Keyword(s):  
Standard Deviation ◽  
Correlation Coefficient ◽  
The Other ◽  
Clusters Of Galaxies ◽  
Number Of Clusters ◽  
Abell Clusters ◽  
The Mean ◽  
Abell Cluster ◽  
Image Position

An attempt is made to establish the membership of Abell clusters in superclusters of galaxies. The relation is used to calibrate the distances to the clusters of galaxies with two redshift estimates. One is m10, the magnitude of the ten-ranked galaxy, and the other is the “mean population,” P, defined by: where p = 40, 65, 105 … galaxies for richness groups 0, 1, 2 …, and r is the apparent radius in degrees given by: The first iteration for redshift, z1, is obtained from m10 alone: The standard deviation for Eq. (1) is 0.105, the number of clusters with known velocities is 342 and the correlation coefficient between observed and fitted values is 0.921. With zi from Eq. (1), we define Cartesian galactic coordinates Xi = Rih−1 cosBi cosLi, Yi = Rih−1 cosBi sinLi, Zi = Rih−1 sinBi for each Abell cluster, i = 1, …, 2712, where Ri is the distance to the cluster (Mpc), and Ho = 100 h km s−1 Mpc−1.

scholarly journals A Morphological Classification of Clusters of Galaxies from Einstein Images

1982 ◽  
Vol 97 ◽  
pp. 97-106 ◽  
Author(s):  
C. Jones ◽  
W. Forman
Keyword(s):  
Line Emission ◽  
Stellar Systems ◽  
Single Individual ◽  
Clusters Of Galaxies ◽  
Morphological Classification ◽  
Iron Line ◽  
Emission Process ◽  
X Ray ◽  
Extended Sources

The earliest Uhuru observations showed that cluster X-ray sources were not associated with single individual galaxies but were extended sources (Gursky et al. 1971, Kellogg et al. 1972, and Forman et al. 1972). The detection of iron line emission from X-ray spectroscopic observations (Mitchell et al. 1976 and Serlemitsos et al. 1977) showed both that the dominant X-ray emission process was thermal bremsstrahlung and that the gas had been processed through stellar systems before being injected into the intracluster medium.

scholarly journals Diffuse Cluster Radio Sources

1996 ◽  
Vol 175 ◽  
pp. 333-338 ◽  
Author(s):  
L. Feretti ◽  
G. Giovannini
Keyword(s):  
Surface Brightness ◽  
Radio Galaxy ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Rare Phenomenon ◽  
Low Surface Brightness ◽  
Extended Sources ◽  
Formation And Evolution

Diffuse radio sources in clusters remain a poorly understood phenomenon. They are very extended sources (0.4-0.6 Mpc), of low surface brightness and steep spectrum, which cannot be identified with any active radio galaxy. They are a rare phenomenon, as they have been found so far in few clusters of galaxies. This paper reviews the current findings about this kind of sources, and the suggestions about their formation and evolution.

Radio Data on Clusters of Galaxies from the Culgoora Circular Array

1983 ◽  
Vol 5 (1) ◽  
pp. 114-129 ◽  
Author(s):  
O. B. Slee ◽  
Betty C. Siegman
Keyword(s):  
Low Frequency ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Circular Array ◽  
Radio Data ◽  
Contour Maps ◽  
Flux Data ◽  
Intensity Measurements ◽  
Half Power ◽  
Selection Of

The Culgoora circular array (CCA) is a 3-km-diameter ring of 96 reflectors operating at 80, 160 and 327 MHz. It has an effective collecting area of ~ 6000 m2 and achieves angular resolutions (full half-power beamwidths) of 3’.70, 1 ‘.85 and 0’.92 at the three operating frequencies. During the interval 1978-1981 we have used the CCA to make 80 and 160 MHz measurements of a comprehensive selection of radio sources which were detected during various complete surveys of clusters of galaxies (see Table 1). We have combined our low-frequency intensity measurements with other available higher-frequency flux data to compute accurate radio spectra. The 160 MHz contour maps for many of the cluster fields were used to find positions and angular sizes for the associated radio sources.

scholarly journals Spatial Variation of CO Excitation in High-z Galaxies

2012 ◽  
Vol 8 (S292) ◽  
pp. 253-253
Author(s):  
Chelsea E. Sharon ◽  
Andrew J. Baker ◽  
Andrew I. Harris ◽  
Dieter Lutz ◽  
Linda J. Tacconi
Keyword(s):  
Spatial Variation ◽  
Gravitational Lensing ◽  
Early Stage ◽  
High Redshift ◽  
Molecular Gas ◽  
Very Large Array ◽  
Star Forming ◽  
Spatially Extended ◽  
Frequency Coverage ◽  
Extended Sources

AbstractPrevious studies of the molecular gas excitation in high-redshift galaxies have focused on galaxy-wide averages of CO line ratios. However, it is possible that these averages hide spatial variation on sub-galactic scales, disguising the true distribution and conditions of the molecular gas within star-forming galaxies. Even in the pre-ALMA era we have begun to see evidence for spatial variation of CO excitation in both rest-UV selected and submillimeter-selected galaxies at z > 2, aided both by the increased frequency coverage of the Jansky Very Large Array (allowing high-resolution observations of the CO(1–0) line, the best tracer for the coldest molecular gas) and by the benefits of gravitational lensing for spatially extended sources. We show new results for multiple high-redshift systems that reveal spatial and/or spectral variations in CO excitation, including an early-stage merger that has different conditions in its two components, thereby illustrating the need for high spatial and spectral resolution mapping in order to accurately characterize the molecular ISM in high-z galaxies.

Radio Sources in Clusters of Galaxies

1977 ◽  
Vol 4 (1) ◽  
pp. 311-319
Author(s):  
Ian McHardy
Keyword(s):  
High Resolution ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Cluster Centre ◽  
Cluster Of Galaxies ◽  
Abell Cluster ◽  
Statistical Sample

Sixty-five radio sources in the 4C catalogue lie within 0.3 of the radius, Rc, defined by Abell (1958), of the centre of an Abell cluster of galaxies. Statistically few of these are expected to be chance coincidences and hence they provide a well defined statistical sample of sources in rich clusters of galaxies. Over the last 6 years sources from this sample having declinations greater than 10° have been observed with high resolution using the Cambridge One-Mile telescope by Slingo (1974(a) and (b)), Riley (1975) and by myself (1977, in preparation). The number of sources observed and the number expected by chance at different distances from the cluster centre are shown in Table I; the radio positions used are from the 4C catalogue.

scholarly journals A VLA Survey of Rich Clusters of Galaxies. I. Whole-cluster Maps, Source List and Source Statistics

1989 ◽  
Vol 42 (6) ◽  
pp. 633 ◽  
Author(s):  
OB Slee ◽  
RA Perley ◽  
Betty C Siegman
Keyword(s):  
Flux Density ◽  
Clusters Of Galaxies ◽  
Large Array ◽  
Spectral Indices ◽  
Cluster Radius ◽  
Very Large Array ◽  
Cluster Membership ◽  
Cluster Centre ◽  
5 Ghz

We have surveyed 58 fields near rich clusters of galaxies with the Very Large Array using scaled arrays in the B/C and/or C/O configurations at 1�5 GHz and 4�9 GHz. The fields were centred on steep spectrum sources in or near clusters that were earlier surveyed with lower resolution telescopes. The whole-field maps at 1�5 GHz are given and a list of 940 sources with 1�5 GHz flux densities down to -1 mJy is presented. Spectral indices of sources within 5' of the field centres are given. Complete flux-limited samples of sources are used to establish a criterion for cluster membership. Sources with total 1�5 GHz flux density >20 mjy and closer to the cluster centre than 0�28 of the cluster radius (a total of 57 sources) are accepted as cluster members.

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