Please note that the contents of the Abell Catalogue data files are corrected from the tables published in Ap. J. Suppl. 70, 1, 1989 (see this paper for the references mentioned here). The data have also been rearranged into two lines for each cluster to allow easy use with 80 column computer terminal displays (not so much of a problem any more, I admit ...).
There are seven files. The four data files are:
The three files of notes apply only to the southern survey:
The notes files have only three columns: the cluster number, the Southern Sky Survey field number on which the cluster was seen, and the Note. Notes made by Olowin are in upper case type, while those made by Abell and Corwin are in lower case type.
The data files have identical formats. An example with column headings is given below. Note that the northern Abell catalogue does not list xcen, ycen, Abell type, m1, m3, m10, previous listings, or number of plates and observers. The northern catalogue has also had all known errors corrected (Struble and Rood 1987a, Leir 1976 as reported by Struble and Rood 1987a, and Corwin 1972 unpublished).
Note also that many typographical errors in the richness and distance classes are present in the 1989 printed version of the catalogue. These incorrect data are NOT present in the machine-readable version accompanying this file; they were introduced in the printing process. There are also a few incorrect redshifts in the printed version; again, this machine-readable version is correct.
Heinz Andernach has found that the galaxy counts for three clusters (Abell 1254, 1366, and 3741) do not agree with the richness classes given in the original Abell catalogues of 1958 or 1989. The oldest data files still in my possession -- from the 1979 updating of the northern catalogue by Abell and his UCLA students at the time, and from our original files for the southern catalogue -- carry the counts and richness classes given here, so it is not possible to now say which numbers are correct. Examination of the clusters suggests that the counts are wrong, but we urge researchers to exercise their own judgment when working on these particular clusters, or indeed, on any of the clusters.
Heinz has kindly communicated several additional corrections to us; these are also included in the present versions of the files.
| Column | Contents |
| Abell | Running number ("Abell" number) in order of right ascension for 1855 as listed by Abell (1958) for the northern clusters (1 to 2712) and in order of right ascension for 1950 for the southern clusters (2713 to 4076). The supplementary southern clusters are numbered from S1 to S1174. |
| Position (1950) | Right Ascension and Declination for 1950 of the apparent cluster center. When the cluster was found in more than one field, a mean position is listed. For the southern clusters, Abell and Corwin used overlays positioned with respect to SAO stars to estimate the position, while Olowin calculated positions from his measured rectangular coordinates. Thus, Olowin's positions were given double weight when means were taken. Abell estimated the positions of the northern clusters with respect to BD stars on the BD charts. |
| Field | The Southern Sky Survey Field number in which the cluster is located. For clusters found in two or more fields, the field given is the one in which the cluster is closest to the plate center. |
| xcen, ycen | Rectangular coordinates in millimeters of the apparent cluster center, referred to the CENTER of the Southern Sky Survey Field given in the previous column. The field centers are defined by the crosses near the edges of the plates. The positive x direction is to the east (left) and the positive y direction is to the north (top). These are in the same sense as the rectangular coordinates given by Lauberts (1983) in the ESO/Uppsala Catalogue, and are listed to facilitate location of the cluster on the 5 x 5 degree ESO 1.0-m Schmidt portion of the Southern Sky Survey. Abell and Corwin measured rectangular coordinates from the left and bottom edges of the plates, so the xcen and ycen from their data are calculated assuming that the plate center is 164 millimeters from the left and bottom crosses on the plates (they also measured the crosses). Olowin referred his rectangular coordinates directly to the plate center as defined by the crosses, so no transformation is necessary for his data. |
| Abell Type | Cluster classification in Abell's system: I = irregular, R = regular, IR and RI = intermediate. ":" indicates a mean type with differences between estimates of two steps, or an uncertain type estimate; "?" indicates a mean type with differences between estimates of three steps, or a questionable type estimate. |
| Bautz-Morgan Type | Classification in the Bautz-Morgan system (Bautz and Morgan 1970). ":" indicates a mean type with differences between estimates of two steps, or an uncertain type estimate; "?" indicates a mean type with differences between estimates of three or more steps, or a questionable type estimate. For the northern catalogue, these types are primarily from Leir and van den Bergh (1977). Other sources for the northern catalogue are Bautz and Morgan (1970), Bautz (1972), Corwin (1974), Kristian et al. (1978), Sandage et al. (1976), and White (1978). |
| Count | Number of cluster members between m3 and m3+2, corrected for background contamination using a) the "universal" luminosity function from Rainey (1976) for the southern clusters and b) local background counts for the northern clusters. The southern counts are corrected to the system of the northern catalogue (see text). |
| m1 | Weighted mean total V magnitude estimate for the first-ranked cluster member. NO GALACTIC EXTINCTION CORRECTION HAS BEEN APPLIED. ":" indicates a mean magnitude with a standard deviation of more than +-0.5 mag, or an uncertain magnitude estimate. "?" indicates a mean magnitude with a standard deviation of more than +-1.0 mag, or a questionable magnitude estimate. "*" indicates that the magnitude estimate is for a known or probable foreground object. |
| m3 | Weighted mean total V magnitude estimate for the third-ranked cluster member, again UNCORRECTED for galactic extinction. Uncertainty symbols as for m1. |
| m10 | Weighted mean total V magnitude estimate for the tenth-ranked cluster member, again UNCORRECTED for galactic extinction. Uncertainty symbols as for m1 and m3. |
| Column | Contents |
| Position (2000) | RA and Dec of the apparent cluster center precessed to the equinox of 2000. |
| Previous Listings | Sources of previous listings: B = Braid and MacGillivray (1978), D = Duus and Newell (1977), d = Dressler (1980), K = Klemola (1969), O = Olowin (1987), Q = Quintana and White (1980 and private communication), Rose (1976), S = Sersic (1974), and s = Snow (1970). Even though all questionable cases of cross identification were checked on the Southern Sky Survey, there remain a few uncertain cases. These are given in the Notes to the Catalogue. |
| xll, yll | Rectangular coordinates of the apparent cluster center, referred to the south-east (lower left) edge of the Southern Sky Survey Field given in the first line. The field edges are defined by the crosses near the edges of the plates; thus, it is possible for these coordinates to be negative. Olowin's data were transformed assuming that the plate center is 164 millimeters from the crosses. For the northern catalogue, the coordinates in these columns are taken from Sastry and Rood (1971), and are again referred to the lower left (south east) corner of the Palomar Sky Survey prints. |
| l and b | Galactic coordinates of the apparent cluster centers, calculated from the 1950 equatorial coordinates. |
| z | Cluster redshift from the lists by Struble and Rood (1987b, northern Abell clusters), Huchra's 1986 collection of published redshifts (Huchra, private communication), Fairall (1985), Corwin (1981; see also Corwin and Emerson 1982), Couch and Newell (1981 and private communication), Noonan (1981), and Spinrad (private communication). The redshift is in parentheses if it is more than 0.3 dex from the expected redshift for the cluster's m10. Redshifts from Huchra's list and from Fairall (1985) were determined by selecting all galaxies with known redshifts within one Abell radius of the cluster center, rejecting discordant redshifts, and averaging the remainder. |
| R | Richness class as defined by Abell (1958). For the northern catalogue, this is Abell's original richness class. |
| D | Distance class corresponding to Abell's (1958) criteria. For the northern clusters, this is Abell's original distance class from his m10. For the southern catalogue, these are from the m10A's listed in the next column. |
| m10A | Magnitude for the tenth-ranked cluster member in Abell's (1958) system, corrected for galactic extinction following Abell's formula. For the northern Abell catalogue, this is Abell's original magnitude. For the southern catalogue, these were transformed from the m10 on the first line (see text). |
| Number and Observers | Number of fields in which the cluster was found, and the observer's initial (A = Abell, C = Corwin, O = Olowin). |
Abell RA (1950) Dec Field xcen ycen Ab Type B-M Count m1 m3 m10
No. (2000) Lists xll yll l b z R D m10A nObs
3743 21 3.4 -27 19 F464 -25 147 IR II-III ( 65) 16.0 17.3 19.2
21 6.8 -27 6 BDORs 189 311 19.28 -40.46 (.1136) 1 5 17.2 1O
3744 21 4.3 -25 41 F530 -142 -35 IR: II-III 70? 13.1: 13.5 14.5:
21 7.5 -25 28 306 129 21.41 -40.22 1 2 14.5 2C
3745 21 4.3 -47 37 F235 35 130 R II-III 96: 18.0? 18.2? 18.8:
21 8.0 -47 24 129 294 352.22 -42.35 2 5 17.2 1C,1O,1A
3746 21 5.1 -36 13 F402 -75 -64 R II 44 15.6 16.7 18.2
21 8.3 -36 0 239 100 7.66 -42.30 0 5 17.1 1O,1C
3747 21 5.4 -43 42 F286 50 70 IR I-II 44: 12.7 13.4 15.0
21 9.1 -43 29 114 234 357.52 -42.74 0 3 15.0 1O
3748 21 6.0 -78 26 F026 14 81 IR III 50 17.1 17.7 18.8
21 12.2 -78 13 KOS 150 245 314.46 -33.44 .1907 1 5 17.0 1O
3749 21 6.9 -46 1 F286 62 -55 IR III 55 15.7 16.4 17.6
21 11.1 -45 48 102 109 354.34 -43.01 1 5 17.0 1O
3750 21 10.6 -49 48 F235 87 10 R II-III: 99 17.7 18.0 18.5
21 14.6 -49 35 77 174 349.11 -43.21 2 5 17.1 1C
Latest update: 14 January 2014