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The 2dF galaxy redshift survey: clustering properties of radio galaxies
The clustering properties of local, S1.4 GHz>= 1 mJy,radio sources are investigated for a sample of 820 objects drawn fromthe joint use of the Faint Images of the Radio Sky at 20 cm (FIRST) and2dF Galaxy Redshift surveys. To this aim, we present 271 newbJ<= 19.45 spectroscopic counterparts of FIRST radiosources to be added to those already introduced in our previous paper.The two-point correlation function for the local radio population isfound to be entirely consistent with estimates obtained for the wholesample of 2dFGRS galaxies. From measurements of the redshift-spacecorrelation function ξ(s) we derive a redshift-space clusteringlength s0= 10.7+0.8-0.7 Mpc, while fromthe projected correlation function Ξ(rT) we estimate theparameters of the real-space correlation function ξ(r) =(r/r0)-γ, r0=6.7+0.9-1.1 Mpc and γ= 1.6 +/- 0.1, where h=0.7 is assumed. Different results are instead obtained if we onlyconsider sources that present signatures of active galactic nucleus(AGN) activity in their spectra. These objects are shown to be verystrongly correlated, with r0=10.9+1.0-1.2 Mpc and γ= 2 +/- 0.1, a steeperslope than has been claimed in other recent works. No difference isfound in the clustering properties of radio-AGNs of different radioluminosity. Comparisons with models for ξ(r) show that AGN-fuelledsources reside in dark matter haloes more massive than~1013.4 Msolar, higher than the correspondingfigure for radio-quiet quasi-stellar objects. This value can beconverted into a minimum black hole mass associated with radio-loud,AGN-fuelled objects of MminBH~ 109Msolar. The above results then suggest - at least forrelatively faint radio objects - the existence of a threshold black holemass associated with the onset of significant radio activity such asthat of radio-loud AGNs; however, once the activity is triggered, thereappears to be no evidence for a connection between black hole mass andlevel of radio output.
| An image database. II. Catalogue between δ=-30deg and δ=70deg.
A preliminary list of 68.040 galaxies was built from extraction of35.841 digitized images of the Palomar Sky Survey (Paper I). For eachgalaxy, the basic parameters are obtained: coordinates, diameter, axisratio, total magnitude, position angle. On this preliminary list, weapply severe selection rules to get a catalog of 28.000 galaxies, wellidentified and well documented. For each parameter, a comparison is madewith standard measurements. The accuracy of the raw photometricparameters is quite good despite of the simplicity of the method.Without any local correction, the standard error on the total magnitudeis about 0.5 magnitude up to a total magnitude of B_T_=17. Significantsecondary effects are detected concerning the magnitudes: distance toplate center effect and air-mass effect.
| An extragalactic database. I - The Catalogue of Principal Galaxies
The Catalogue of Principal Galaxies is described, which lists equatorialcoordinates (for the equinoxes 1950 and 2000) and cross-identificationsfor 73,197 galaxies. The 40,932 coordinates have standard deviationssmaller than 10 arcsec. A total of 131,601 names from the 38 most commonsources are listed. In addition, mean data for each object are givenwhen available: 49,102 morphological descriptions, 52,954 apparent majorand minor axes, 67,116 apparent magnitudes, 20,046 radial velocities and24,361 position angles. This information was used for facilitatingproper identification. Finally, distribution options are explained.
| A catalog of morphological types in 55 rich clusters of galaxies
Data are presented from a study of 55 rich clusters of galaxies. Thedata include positions, morphological types, estimated total magnitudes,bulge sizes, and ellipticities for about 6000 galaxies, as determinedfrom high scale photographic plates. Data reduction procedures aredescribed, and a brief analysis of cluster richness, which indicatesthat Abell richness classes are only rough indicators of total clustermembership, is included.
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