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The I-Band Tully-Fisher Relation for SC Galaxies: Optical Imaging Data
Properties derived from the analysis of photometric I-band imagingobservations are presented for 1727 inclined spiral galaxies, mostly oftypes Sbc and Sc. The reduction, parameter extraction, and errorestimation procedures are discussed in detail. The asymptotic behaviorof the magnitude curve of growth and the radial variation in ellipticityand position angle are used in combination with the linearity of thesurface brightness falloff to fit the disk portion of the profile. TotalI-band magnitudes are calculated by extrapolating the detected surfacebrightness profile to a radius of eight disk scale lengths. Errors inthe magnitudes, typically ~0.04 mag, are dominated by uncertainties inthe sky subtraction and disk-fitting procedures. Comparison is made withthe similar imaging database of Mathewson, Ford, & Buchhorn, both aspresented originally by those authors and after reanalyzing theirdigital reduction files using identical disk-fitting procedures. Directcomparison is made of profile details for 292 galaxies observed incommon. Although some differences occur, good agreement is found,proving that the two data sets can be used in combination with onlyminor accommodation of those differences. The compilation of opticalproperties presented here is optimized for use in applications of theTully-Fisher relation as a secondary distance indicator in studies ofthe local peculiar velocity field.
| Structure and kinematics of galaxy clusters. I. The redshift catalogue.
An extensive redshift survey has been conducted on a sample of 15 nearby(0.01<~z<~0.05) clusters of galaxies. A total number of 860redshifts were determined by fitting of emission-lines and/orcross-correlation techniques. Of this sample, 735 galaxies are within0.2-0.8Mpc (H_0_=50km/s/Mpc) of the center of clusters. Approximatemorphological types are available for most of the galaxies. A comparisonof the present redshifts with published data allows an extensive erroranalysis. The agreement is excellent with the most modern data, showinga zero point error of 5km/s and an overall consistency of themeasurements and their uncertainties. We estimate our redshifts to havemean random errors around 30km/s. A population analysis of the clusterswill be given in a forthcoming paper.
| Linear clusters of galaxies - A999 and A1016
Redshifts have been measured for galaxies in two of the 'linear'clusters of the sample of Adams, Strom, and Strom (1980), including 44redshifts in A999 and 40 in A1016. From the data, it is concluded thatthe galaxies in A999 are probably drawn from a spherically symmetricdistribution, while those in A1016 probably are not. Both A999 and A1016have mass-to-light ratios lower than typical of other clusters. Theeffect of anisotropy on the determination of cluster masses from thevirial theorem is examined, and it is found that if the shortest axes ofthese clusters are close to the line of sight, the mass-to-light ratiomay be underestimated by about 50 percent. No significant evidence isfound for alignments of individual cluster members with the cluster axisin the convincing linear cluster A1016. There is similarly no evidenceof segregation by luminosity morphological type in A1016.
| Linear clusters of galaxies
Seven linear clusters of galaxies from the catalog of Rood and Sastryhave been studied primarily to determine whether the principal axes ofthe member galaxies exhibit any tendency toward alignment. The majoraxes of galaxies in two of the clusters (Abell 999 and Abell 2197) showa distinct tendency to lie along the cluster major axes. Examination ofall the galaxies in our seven-cluster sample reveals that the major axesof these cluster members tend to lie either along or perpendicular tothe cluster major axis and avoid intermediate position angles. For thissample, there appears to be no correlation between E-galaxy flatteningand cluster shape, a result in contradiction to the recent study byStrom and Strom of ellipticals located in nine clusters of greaterrichness. Significant evidence of mass segregation is found in twoclusters (Abell 179 and Abell 194).
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