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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.
| Forbidden O III emission in two magnitude-limited field-galaxy surveys
The paper presents emission-line strengths for 394 galaxies from thefield-galaxy redshift surveys of Kirshner, Oemler, and Schechter (1978)and Kirshner et al. (1983) as part of a study of the nature of field andvoid galaxies. These data are 95 percent complete in their coverage ofthe forbidden O III 5007, 4959 A emission lines. It is found that 8.8 +or - 1.5 percent of a J magnitude-limited data set have forbidden O III5007 A emission equivalent widths greater than 10 A. There is noevidence that the spatial distribution of emission-line galaxies in eachfield differs from that of galaxies without emission. However, there isa significant increase in the fraction of galaxies with strong forbiddenO III emission in the southern fields of the Kirshner, Oemler, andSchechter (1978) survey as compared with the other survey fields. Theresults are consistent with the conclusion that the fraction of galaxieswith emission is larger in the Bootes void than in the general field,but tighter constraints on the void normal galaxy population are neededto improve the statistics.
| The structure of brightest cluster members. II - Mergers
Surface photometry of 342 bright elliptical galaxies in 103 clusters isanalyzed for evidence of mergers. Structural differences betweenbrightest cluster members (BCMs) and normal ellipticals can besummarized as having enlarged characteristic radii and shallow profileslopes (beta greater than -1.7). Profile morphology criteria for theelliptical types gE, D, and cD are outlined. Comparison of observationswith numerical simulations of mergers strongly suggests a past historyof dynamical growth for BCMs. Weak correlations of global clusterproperties to BCMs supports the hypothesis proposed by Merritt (1984)that mergers are important in early subgroups before virialization andformation of a cluster identity.
| A study of field galaxies. I - Redshifts and photometry of a complete sample of galaxies
As a first step towards a redetermination of the luminosity function andspace distribution of field galaxies, data are presented on amagnitude-limited sample of galaxies in eight fields in the north andsouth galactic polar caps. Redshifts, accurate to about 100 km/s havebeen obtained for 164 of 184 galaxies brighter than J=15.0 (Bapproximately equal to 15.5). Magnitudes and colors have also beenmeasured for a large sample of 807 galaxies, complete to J approximatelyequal to 15.7.
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