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The Hamburg/RASS Catalogue of optical identifications. Northern high-galactic latitude ROSAT Bright Source Catalogue X-ray sources
We present the Hamburg/RASS Catalogue (HRC) of optical identificationsof X-ray sources at high-galactic latitude. The HRC includes all X-raysources from the ROSAT Bright Source Catalogue (RASS-BSC) with galacticlatitude |b| >=30degr and declination delta >=0degr . In thispart of the sky covering ~ 10 000 deg2 the RASS-BSC contains5341 X-ray sources. For the optical identification we used blue Schmidtprism and direct plates taken for the northern hemisphere Hamburg QuasarSurvey (HQS) which are now available in digitized form. The limitingmagnitudes are 18.5 and 20, respectively. For 82% of the selectedRASS-BSC an identification could be given. For the rest either nocounterpart was visible in the error circle or a plausibleidentification was not possible. With ~ 42% AGN represent the largestgroup of X-ray emitters, ~ 31% have a stellar counterpart, whereasgalaxies and cluster of galaxies comprise only ~ 4% and ~ 5%,respectively. In ~ 3% of the RASS-BSC sources no object was visible onour blue direct plates within 40\arcsec around the X-ray sourceposition. The catalogue is used as a source for the selection of(nearly) complete samples of the various classes of X-ray emitters.
| Arcsecond Positions of UGC Galaxies
We present accurate B1950 and J2000 positions for all confirmed galaxiesin the Uppsala General Catalog (UGC). The positions were measuredvisually from Digitized Sky Survey images with rms uncertaintiesσ<=[(1.2")2+(θ/100)2]1/2,where θ is the major-axis diameter. We compared each galaxymeasured with the original UGC description to ensure high reliability.The full position list is available in the electronic version only.
| A catalogue of spatially resolved kinematics of galaxies: Bibliography
We present a catalogue of galaxies for which spatially resolved data ontheir internal kinematics have been published; there is no a priorirestriction regarding their morphological type. The catalogue lists thereferences to the articles where the data are published, as well as acoded description of these data: observed emission or absorption lines,velocity or velocity dispersion, radial profile or 2D field, positionangle. Tables 1, 2, and 3 are proposed in electronic form only, and areavailable from the CDS, via anonymous ftp to cdsarc.u-strasbg.fr (to130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
| A 20 Centimeter VLA Survey of Abell Clusters of Galaxies. VII. Detailed Radio Images
We present detailed radio images, and models, obtained with the VeryLarge Array at 20 cm for 199 radio galaxies in Abell clusters ofgalaxies.
| Optical Spectroscopy of Radio Galaxies in Abell Clusters II. BL Lacs and FR I Unification
As part of our optical spectroscopic study of radio galaxies in Abellclusters, we report a search for BL Lac phenomena in our sample. As anindicator of possible nonthermal activity in the nuclei of our radiogalaxies, we report D(4000), a measure of the 4000 A break, for 190objects. None of the objects in our sample are found which meet thetions for BL Lac objects both for D(4000) and for weakness of emissionlines. We do find 15 objects which have diluted 4000 A breaks[D(4000)<= 1.8], and these are discussed individually. At least fourof them appear to have weak nonthermal activity which may be related tothe BL Lac phenomena. These results appear to be in conflict with thesimplest BL Lac/FR I unification model. Several ways out of this dilemmaare discussed. Perhaps the most likely change in this model is theinclusion of FR II radio galaxies as part of the parent population of BLLac objects.
| A 20 CM Survey of Abell Clusters of Galaxies. V. Optical Observations and Surface Photometry
We present results from a program of optical imaging of 265 radiogalaxies in rich clusters. Using isophotal surface photometry, weinvestigate the optical properties such as the morphology, surface-brightness profiles, surface-brightness/size relationships,ellipticities, and the frequency of nonelliptical isophotes. The resultsare compared to a "normal" nonradio-selected sample of ellipticalgalaxies from the same clusters. The goal is to determine if the parentpopulation of FR I radio galaxies can be distinguished optically fromradio-quiet galaxies. The results of the analysis are that clusterellipticals are a very homogeneous class of objects. The opticalproperties are consistent with a one-parameter family, where the opticalluminosity is the fundamental parameter. In all tests considered, radio-loud FR I galaxies cannot be distinguished optically from radio-quietgalaxies selected from the same environment. The local density of nearbycompanions (<20 kpc) and the frequency of morphological peculiaritiesor tidal interactions are not statistically different between theradio-loud and quiet samples. There is some suggestion from comparisonto published samples of non-cluster radio galaxies, that the clusterenvironment is not condusive to long-lived tidal interactions, and thatsuch events may be more important to galaxy evolution in poor groups andlower density environments. Such events appear to have little influenceon the formation of FR I radio galaxies in rich clusters. The resultsare consistent with the idea that all elliptical galaxies may at sometime (or many times) contain powerful (rR I) radio sources.
| A 20 CM VLA Survey of Abell clusters of galaxies. 4: The radio sample and cluster properties
This is the fourth in a series of papers describing an in depth study ofa large statistical sample of radio galaxies in Abell clusters. Thissample forms the basis of a detailed optical and radio study of the hostgalaxy properties, environments, and evolutionary models for radiogalaxies as a class of objects. In this paper, we examine the radiodetection statistics as a function of cluster morphological type, galaxyrichness, and spatial location within the cluster distribution. Theserelationships are also parameterized as a funtion of radio power. Thespatial distributions of the radio sources as a function of distancefrom the cluster center indicate that radio galaxies are preferentiallylocated at small radii from the center of the cluster potential. This isobserved as a factor of 2-3 excess over that predicted by a King-modelsurface-density distribution. The excess is higher in the upper radiopower bin. This result is easily explained, however, from the spatialdistribution of the brightest galaxies and the relationship betweenradio and optical luminosity. The sample is divided into richnessclasses 0, 1, and 2, according to Abell's criterion. and in two radiopower ranges. While simple counting shows that richer clusters have moreradio galaxies in both radio power bins, when the detections are scaledto the number of galaxies surveyed in each cluster, no significantcorrelations are found. This result implies that the number of radiogalaxies detected simply scales with the number of galaxies surveyed.The higher galaxy density (and presumably higher ICM gas density) inricher clusters does not appear to affect the rate of radio sourceformation. The clusters are divided into Rood-Sastry and Bautz-Morganmorphological types. While it would appear that the more regularclusters have higher radio detection rates, when the classes arenormalized to the number of galaxies, the radio detection rates arefound to be identical regardless of cluster morphology. In conclusion,it is the optical properties of the host galaxy which most influenceboth the radio detection rate and the radio source properties. Thecluster properties, galaxy density, and spatial location of the galaxydo not significantly affect the observed radio statistics.
| Optical spectroscopy of radio galaxies in Abell clusters. 1: Redshifts and emission-line properties
We present results of a program of optical spectroscopy of radiogalaxies in rich clusters. Redshifts are reported for 268 radio galaxiesor close companions in Abell clusters and 36 objects which turned out tobe foreground or background objects. Absolute line strengths are alsoreported for the 3727 A (O II) line and the (N II)/H alpha complex. Wefind no evidence that the radio activity in our sample of mostly FR Iradio galaxies is associated with emission-line luminosities above thosefound in normal galaxies of the same absolute magnitude and opticaltype. We also find that the radial velocity differences between radiogalaxies and the cluster mean seem mainly to be a function of galaxyabsolute magnitude rather than radio properties.
| The kinematics of Abell clusters
Velocity histograms, galaxy positions, and velocity dispersions arepresented for 69 nearby Abell clusters. The shape of the cumulativedistribution for R = 1 or more clusters does not match the predictionsof standard CDM models for any biasing parameter b. The only modelsconsistent with the median and maximum dispersions of the sample arethose of b about 1.6-2.0 and in which clusters are identified in threedimensions. Velocity dispersions of high-redshift systems appearfundamentally different from those of nearby clusters. The mediandispersion of the subset of 25 cD clusters is similar to that of non-cDsystems. A substantial fraction of the cD galaxies have velocitiessignificantly different from the mean of their parent clusters. Three ofthese have 4 s or more measured redshifts. These last two resultssuggest that the formation of cD galaxies is dominated by the local,rather than global, cluster environment.
| A 20 CM VLA survey of Abell clusters of galaxies. I - Distance class of not greater than 3 clusters
Nearby Abell clusters of distance class of not greater than 3 arestudied based on 20-cm VLA observations, Westerbork Synthesis RadioTelescope results, and Einstein Observatory X-ray data. No significantcorrelation is found between the 20-cm radio power and X-ray luminosity,and no evidence is found that regular-type clusters are statisticallymore likely to be radio loud than irregular-type clusters. A weakcorrelation is noted between X-ray-cooling mass-accretion rates andradio powers for central dominant galaxies in cooling-flow clusters,suggesting that either cooling accretion directly fuels the centralengine and/or cooling flows strongly interact with the radio plasma.
| A proposed program of observations of extragalactic X-ray sources
A method is proposed for observationally testing the hypothesis thatactive galactic nuclei contain a massive black hole which is surroundedby an accretion disk serving as an energy source. An observationalprogram of 64 objects, selected using Aldrovandi's (1981) model, isdescribed. It is suggested that as many current electrophotometricalestimations as possible should be made, and that thespectrophotometrical data should cover the 3700-8000-S wavelength range.
| Radial velocities of galaxies detected in the Arecibo 2380 MHz survey
The Loiano telescope's image tube spectrograph was used to obtain thepreviously unknown radial velocities of 50 galaxies detected during theArecibo 2380 MHz survey of bright galaxies, leading to the determinationof 224 radio-detected galaxy redshifts north of 15 deg. Both a 100km/sec typical standard error and minus 60 plus or minus 20 km/secsystematic zero error are derived for the velocities presented, on thebasis of comparisons with other redshift sources made on a furthersample of 35 galaxies.
| 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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