J/AJ/118/2014 Nearby poor clusters of galaxies catalog (White+, 1999) ================================================================================ A catalog of nearby poor clusters of galaxies White R.A., Bliton M., Bhavsar S.P., Bornmann P., Burns J.O., Ledlow M.J., Loken C. =1999AJ....118.2014W (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Clusters, galaxy ; Galaxy catalogs ; Redshifts ; Cross identifications Keywords: catalogs - galaxies: clusters: general Abstract: A catalog of 732 optically selected, nearby poor clusters of galaxies covering the entire sky north of -3{deg} declination is presented. The poor clusters, called WBL clusters, were identified as concentrations of three or more galaxies with photographic magnitudes brighter than 15.7, possessing a galaxy surface overdensity of 10^4/3^. These criteria are consistent with those used in the identification of the original Yerkes poor clusters, and this new catalog substantially increases the sample size of such objects. These poor clusters cover the entire range of galaxy associations up to and including Abell clusters, systematically including poor and rich galaxy systems spanning over 3 orders of magnitude in the cluster mass function. As a result, this new catalog contains a greater diversity of richness and structures than other group catalogs, such as the Hickson and Yerkes catalogs. The information on individual galaxies includes redshifts and cross-references to other galaxy catalogs. The entries for the clusters include redshift (where available) and cross-references to other group and cluster catalogs. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table2.dat 110 732 Poor-cluster catalog table3.dat 90 3324 Poor-cluster galaxies table4.dat 19 219 Previous Nomenclature -------------------------------------------------------------------------------- See also: VII/26 : Uppsala General Catalogue of Galaxies (UGC) (Nilson 1973) VII/49 : Galaxies and Clusters of Galaxies (CGCG) (Zwicky, 1968) VII/118 : NGC 2000.0 (Sky Publishing, ed. Sinnott 1988) VII/190 : Zwicky Galaxy Catalog (Zwicky+ 1968) VII/193 : The CfA Redshift Catalogue, Version June 1995 (Huchra+ 1995) VII/213 : Hickson's Compact groups of Galaxies (Hickson+ 1982-1994) Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 7 A7 --- WBL WBL cluster designation (WBL NNN) 9- 10 I2 h RAh Cluster centroid right ascension (B1950.0) 11- 14 F4.1 min RAm Cluster centroid right ascension (B1950.0) 15 A1 --- DE- Cluster centroid declination sign (B1950.0) 16- 17 I2 deg DEd Cluster centroid declination (B1950.0) 18- 19 I2 arcmin DEm Cluster centroid declination (B1950.0) 21- 23 I3 --- Rich Richness (number of CGCG galaxies in each poor cluster) 25- 43 A19 --- Clust. Clustering at {sigma}_46_ (1) 45- 51 F7.5 --- z ? Poor-cluster redshift (2) 53- 55 I3 --- o_z ? Number of galaxy redshifts available from NED 57- 59 A3 --- n_z Notes on z (3) 61- 71 A11 --- ZWCL Zwicky cluster containing the given WBL cluster within its contours 72- 73 A2 --- n_ZWCL [MD ] MD: medium-distant cluster 75- 77 I3 arcmin RZ ? Radius of the Zwicky cluster 79- 82 F4.2 --- fZ ? Distance separating the center of the Zwicky and WBL clusters, in units of the Zwicky cluster radius (4) 84- 87 I4 --- ACO ? Abell cluster cross-correlation (5) 89- 91 I3 --- CfA ? CfA () group cross-correlation (6) 93- 95 I3 --- HCG ? HCG () cross-correlation (7) 98-112 A15 --- Yerkes Yerkes cluster cross-correlation (8) -------------------------------------------------------------------------------- Note (1): An indication of the fate of each individual galaxy at the higher density enhancement ({sigma}_46_). A single zero in this column indicates that a group at {sigma}_21_ fractured into single galaxies at {sigma}_46_ (i.e., the galaxy apertures did not overlap). Combinations of other numbers indicate how many galaxies were in each subcluster at {sigma}_46_, with "0" indicating one or more isolated galaxies. For example, a cluster with 11 members and an 8+0 in this column becomes a group of eight members with three isolated galaxies at {sigma}_46_. A cluster of 11 members and an entry of 4+3+2+0 breaks up into three subclusters of four, three, and two members, with two isolated galaxies at {sigma}_46_. Note (2): Redshift for the cluster, when available, computed as an average of redshifts from the literature obtained through the NASA Extragalactic Database (NED). Note (3): If there is no note, the number of galaxy redshifts were used to compute the cluster redshift. i: there were only two redshifts available and their values differed by more than 1500km/s. n this case, the two galaxies may be close only in projection. The redshift given in this case is the average of the two galaxy redshifts. ii: Of the three or more redshifts available, one was more than 1500km/s from the mean. After removing this discrepant redshift, a new mean was calculated, with all remaining redshifts within 1500km/s from this new mean. iii: Of the three or more redshifts available, at least two discrepant redshifts were present. The redshift listed is then the mean redshift calculated after removing only the most discrepant velocity. A value of 1500km/s was chosen for the cutoff velocity because a "typical" poor cluster has a velocity dispersion of ~500km/s. This criteria is thus analogous to the standard 3{sigma} lipping often used in the literature. Note (4): The radius is that given in the CGCG and is meant to indicate the area on the sky contained within the hand-drawn contours. Zwicky clusters are rarely spherical, so all correlations were verified by eye. Zwicky clusters are also separated into estimated distance classes, with near clusters meant to be in the redshift range 0.0) Note (2): Measure of the number of nearest neighbors to the galaxy at {sigma}_21_ (N21) and {sigma}_46_ (N46). This refers to the number of neighbor galaxies falling within the aperture defining the {sigma}_21_ or {sigma}_46_ threshold. For a galaxy with no nearest neighbor, the aperture radius is 0.084{deg} at {sigma}_21_ and 0.057{deg} at {sigma}_46_. The radius scales as (n+1)^1/2^, where n is the number of nearest neighbors. For an individual galaxy, the higher the number, the more centrally located it is within the poor cluster. Multiple poor-cluster members with high numbers of neighbors indicate a compact cluster. Galaxies with a nearest neighbor number of zero were merged into a cluster because a nearby galaxy possessed many neighbors. The resulting large aperture [{prop.}(n+1)^1/2^] may have overlapped an isolated galaxy in some cases. Note (3): An indication of the fate of each individual galaxy at the higher density enhancement. A blank field indicates that the galaxy became isolated (no neighbors and no overlapping apertures) and therefore was not considered a member of a cluster at {sigma}_46_. Galaxies with the same letters are part of the same poor cluster at {sigma}_46_. WBL designations for these subgroups should include this letter and indicate that it is a {sigma}_46_ cluster. Note (4): Several Zwicky galaxies are actually multiple galaxies and therefore have multiple identifications in NED. In these instances, the average of all redshifts available for the Zwicky galaxy is presented. Note (5): Cross identifications for the galaxies from the NGC, IC (See Cat. ) and UGC (Cat. ) catalogs obtained from NED. For entries that are actually multiple galaxies, all relevant identifications are presented. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 8 A8 --- Name Identification (1) 10- 16 A7 --- WBL WBL designation 18- 19 A2 --- Note [abc ] Note when no WBL poor cluster associated with a Yerkes cluster (2) -------------------------------------------------------------------------------- Note (1): This table cross-references the names of the poor clusters presented here with previous names used in the literature. We also present a direct comparison of the WBL clusters with the Yerkes (AWM (Albert et al., 1977ApJ...211..309A, MKW (Morgan et al., 1975ApJ...199..545M) and WP (White, 1978ApJ...226..591W)) poor clusters. We list every Yerkes poor cluster along with any corresponding WBL cluster. Note (2): a: Cluster galaxies were too faint to be included in the WBL catalog. b: Cluster is too diffuse to meet the galaxy density criterion of the WBL catalog. c: Cluster is south of -3{deg} declination and therefore not included in the WBL catalog. -------------------------------------------------------------------------------- History: From AJ electronic version ================================================================================ (End) James Marcout, Patricia Bauer [CDS] 10-Jan-2000