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|The UZC-SSRS2 Group Catalog|
We apply a friends-of-friends algorithm to the combined Updated ZwickyCatalog and Southern Sky Redshift Survey to construct a catalog of 1168groups of galaxies; 411 of these groups have five or more members withinthe redshift survey. The group catalog covers 4.69 sr, and all groupsexceed the number density contrast threshold, δρ/ρ=80. Wedemonstrate that the groups catalog is homogeneous across the twounderlying redshift surveys; the catalog of groups and their membersthus provides a basis for other statistical studies of the large-scaledistribution of groups and their physical properties. The medianphysical properties of the groups are similar to those for groupsderived from independent surveys, including the ESO Key Programme andthe Las Campanas Redshift Survey. We include tables of groups and theirmembers.
|Kinematics of the Hercules supercluster|
The Hercules supercluster consists of the Abell clusters A2147, A2151,and A2152. Previous studies of the kinematics have been confounded bythe difficulty of correctly assigning galaxies to the individualclusters, which are not well separated. Our study has a total of 468available velocities for galaxies in the region, 175 of them new. Thereare 414 galaxies in the supercluster, about three times the number usedin the previous supercluster study. We verify the existence of the threeindividual clusters and compute their individual dynamical parameters.We investigate several techniques for assigning galaxy membership toclusters in this crowded field. We use the KMM mixture-modelingalgorithm to separate the galaxies into clusters; we find that A2152 hasa higher mean velocity than previous studies have reported. A2147 andA2152 also have lower velocity dispersions: 821 and 715 km/s,respectively. The assignment of galaxies to either A2152 or A2147requires velocity and position information. We study the kinematics ofthe supercluster using the two-body formalism of Beers et al. (1982) andconclude that A2147 and A2151 are probably bound to each other and thatthe supercluster as a whole may also be bound. The mass of thesupercluster, if bound, is (7.6 +/- 2.0) 10 exp 15/h M(solar); with thesupercluster luminosity, (1.4 +/- 0.2) 10 exp 13/sq h L(solar), thisyields 0.34 +/- 0.1.
|Total magnitude, radius, colour indices, colour gradients and photometric type of galaxies|
We present a catalogue of aperture photometry of galaxies, in UBVRI,assembled from three different origins: (i) an update of the catalogueof Buta et al. (1995) (ii) published photometric profiles and (iii)aperture photometry performed on CCD images. We explored different setsof growth curves to fit these data: (i) The Sersic law, (ii) The net ofgrowth curves used for the preparation of the RC3 and (iii) A linearinterpolation between the de Vaucouleurs (r(1/4) ) and exponential laws.Finally we adopted the latter solution. Fitting these growth curves, wederive (1) the total magnitude, (2) the effective radius, (3) the colourindices and (4) gradients and (5) the photometric type of 5169 galaxies.The photometric type is defined to statistically match the revisedmorphologic type and parametrizes the shape of the growth curve. It iscoded from -9, for very concentrated galaxies, to +10, for diffusegalaxies. Based in part on observations collected at the Haute-ProvenceObservatory.
|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.
|The complex structure of Abell 2151 (Hercules)|
We analyzed the space distribution of 117 galaxies in an area of 0.9 degradius centered on NGC 6045 in the Hercules cluster in the velocityrange 9000 to 14,000 km/s. By taking advantage of 74 morphologies basedon CCD images, we succeed in isolating a cluster of galaxies with anaverage velocity of 11,467 km/s located to the NE of the assumedcentroid of A2151, where early and late type galaxies share the samedynamical properties. The implications of this result for the nature andidentification of the x-ray source is briefly discussed.
|Dark matter and dynamics in the Hercules Cluster (A2151)|
New 21-cm observations of faint spiral galaxies in the Hercules cluster(A2151) are presented in order to investigate the dynamics throughoutthe cluster core, out to a projected radius of 1.8/h Mpc. The globaldynamical mass of Hercules is calculated using the virial theorem andthe projected mass estimator. These masses lie in the range 3-9 x 10 exp14 solar masses. The importance of subclustering in A2151 by eye isexamined via the statistical test of Dressler & Shectman (1988), andby considering the effects of the detected substructure on the dynamicalmass determination. The clumpy distribution is interpreted as a signthat the galaxies in the cluster have not reached dynamical equilibriumin the gravitational potential.
|Far-infrared properties of cluster galaxies|
Far-infrared properties are derived for a sample of over 200 galaxies inseven clusters: A262, Cancer, A1367, A1656 (Coma), A2147, A2151(Hercules), and Pegasus. The IR-selected sample consists almost entirelyof IR normal galaxies, with Log of L(FIR) = 9.79 solar luminosities, Logof L(FIR)/L(B) = 0.79, and Log of S(100 microns)/S(60 microns) = 0.42.None of the sample galaxies has Log of L(FIR) greater than 11.0 solarluminosities, and only one has a FIR-to-blue luminosity ratio greaterthan 10. No significant differences are found in the FIR properties ofHI-deficient and HI-normal cluster galaxies.
|A catalog of galaxies in Hercules from the Palomar Sky Survey and the Minnesota Automated Plate Scanner|
The development of galaxies catalogs from the Palomar Sky Survey usingthe Minnesota Automated Plate Scanner (APS) is examined. The design andoperation of APS are described. The algorithm used to distinguish starsfrom galaxies is discussed, and the completeness and confusion of thealgorithm as a function of magnitude are estimated. The quality of thephotometric calibration for galaxy magnitudes and surface-brightnessthresholds is evaluated. The relation between the distribution of colorsand morphological types is studied. The luminosity functions forHercules galaxies are calculated and presented. The catalog generatedusing the APS is 80 percent complete; photometry good to 0.23 mag rms ispossible; and J-F colors are good to 0.17 mag rms.
|The Distance to the Hercules Supercluster. II. Application of Tertiary Indicators and an Estimate of the Hubble Constant|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1986ApJS...62..283B&db_key=AST
|The distance to the Hercules supercluster. I - Basic data for 220 galaxies in CGCG field 108.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1986ApJS...62..255B&db_key=AST
|A catalog of radio, optical, and infrared observations of spiral galaxies in clusters|
The results of a major observational program on the luminosities,colors, and gas contents of spiral galaxies in clusters of galaxies arepresented. The data have been used as part of a detailed investigationinto the nature of cluster spirals and for revisions of the distancescale using the infrared Tully-Fisher relation. The observationalstrategies, reduction procedures, and sources or error are brieflydiscussed. The data include 21-cm H I observations, UBVR multiaperturephotometry, and H-band photometry of several hunderd spiral galaxies in10 clusters.
|Gas deficiency in cluster galaxies - A comparison of nine clusters|
The available 21 cm line data in the literature for galaxies in nineclusters is combined with new high-sensitivity observations of 51galaxies in five of the nine clusters in order to test fordiscriminating circumstances between those clusters which show H Ideficiency among their spiral population and those which do not. An H Ideficiency for the complete cluster sample is derived employing acomparison sample of galaxies chosen from the Catalog of IsolatedGalaxies. The deficiency and its radial dependence is summarized foreach cluster and a composite. A comparison of the environments indifferent clusters leads to the conclusion that the occurrence of H Ideficiency is correlated with the presence of a hot X-ray intraclustermedium, and that an ongoing interaction process is active through thecores of X-ray clusters.
|The infrared properties of galaxy clusters - IRAS observations of the Hercules Cluster (Abell 2151)|
A total of 41 sources have been detected at 60 microns to a level of 50mJy in a 1.6 x 0.5 deg field centered on the rich galaxy cluster Abell2151. Twenty-four of these sources can be identified with late-typespiral galaxies of estimated photographic magnitude 17 or brighter.Galaxies classified as E or S0 are notably absent in the infrared data.Within the field, eleven of the IRAS sources cannot be easily identifiedwith galaxies in the Hercules Cluster. If the brightest 60 microncluster source (NGC 6045) is neglected, the integral luminosity functionin the far-infrared can be fitted well with two power laws of slope -1.1and -2.5.
|Inner ring structures in galaxies as distance indicators. IV - Distances to several groups, clusters, the Hercules supercluster, and the value of the Hubble constant|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1983ApJ...266....1B&db_key=AST
|The H I content of galaxies in the Hercules supercluster Evidence for sweeping|
Arecibo observations of the neutral hydrogen content of 52 galaxies inthe Hercules supercluster reveal signs of environmental dependence.Supercluster galaxies are compared with a sample of isolated galaxieswith the same luminosity range, and galaxies found at large distancesfrom the condensation appear to have normal M(H)/L ratios, while thosenear the cluster A2147 have marked deficiencies. The deficienciescontrast with the normal to mildly gas deficient A2151, which indicatesthat gas deficiency of spiral galaxies in Hercules is caused by removaldue to ram pressure of the motion of galaxies through the intraclustermedium. Calculations which take into account the intracluster mediumdensity and velocity dispersion indicate the existence of a sweepingmechanism. Optical data also show that swept galaxies with more markedM(H)/L deficiencies tend to be redder than those with a normal ratio,especially in the case of Zw 108-072 in A2147. Results suggest thatsubstantial galactic evolution may be catalyzed by opportuneenvironmental conditions, and a large number of gas deficienct spiralgalaxies undergo a gas-sweeping stage over a relatively short timescale.
|Spiral galaxies in clusters. II - Neutral hydrogen observations in Cancer, Hercules /A 2151/, and Pegasus I|
H I observations with the 305-m Arecibo telescope are reported of 67spiral galaxies in Abell 2151 (Hercules), Peg I, and the Cancerclusters. Systemic velocities, linewidths, and hydrogen masses arecomputed for the 37 galaxies detected, and upper limits on the H Icontent are derived for nondetections. The H I properties of galaxies inPeg I and Cancer are found to closely resemble those of standard, nearby'field' samples. In particular, the distance-independent qualityMH/L sub pg is in essence identical in these fields andcluster samples. Sensitivity to H I for the more distant Herculescluster is much lower, but the present results reveal only one galaxywith a value of MH/L sub pg higher than expected from thestandard sample, while several are lower than expected. It is not clearwhether this is a result of the higher luminosities of these spirals orof other conditions in the cluster.
|Corrections to the Reference Catalogue of Bright Galaxies (Third List)|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972PASP...84..462C&db_key=AST
|Notes on the Hercules Galaxy Cluster|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971PASP...83..320C&db_key=AST
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