Quantitative morphology of isolated E/S pairs of galaxies
We present a study of the morphology and geometry for 22 southern E+Spair candidates using high resolution CCD frames obtained at the ESO 2.2m telescope. We find a considerable number of true mixed pairs withabout 13/11 elliptical + spiral pairs in the present sample. Theremaining objects include about 3 'disky' pairs (composed of S0 and Smembers) and 3 'early-type' pairs comprising E and S0 members. Weestimate that between 10 and 25 percent of the pairs in any complete(non-hierarchical) sample will be of the E+S type. This suggests thatmorphological concordance is not the rule among paired galaxies. Wesuggest that interaction phenomena and the alterations they produce ingalaxy forms may explain many of the mixed pairs. Eight early-typecomponents show possible shell structure while 78 percent show anisophotal twisting of greater than 10 deg. Three of these objects andtwo additional pairs may be mergers in progress based upon their chaoticmorphologies. We suggest that the early-type components in many pairscould be merger products. These E+S pairs might then be a transientstage in the coalescence of compact groups.
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A redshift survey toward a proposed void of galaxies suggested by the distribution of Abell clusters
A program of redshift measurements was carried out in a region of thesky in which a relative under-density of Abell clusters had been used toinfer the presence of a large (diameter about 40/h Mpc) void in thegeneral galaxy distribution. The purpose of this study was toinvestigate whether the large-scale distribution of galaxies is tracedby the distribution of rich clusters. Redshifts are presented for 308galaxies in the Zwicky Catalog in a 234 square degree region centered onR.A. about 2h, Decl. about 12 deg of which 229 have been newly measured.These data reveal a pattern of filamentary structure alternating withvoids of characteristic diameter about 25-30/h Mpc, throughout thevolume sampled. While the redshift data reveal an underdensity in thedistribution of galaxies in the general region suggested by the Abellcluster distribution, they do not support the existence there of a 40/hMpc diameter void.
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Observations of binary galaxies at a frequency of 102 MHz
A total of 93 double galaxies from the Karachentsev list was observedwith the large phased array at the Lebedev Physical Institute at 102MHz. The interplanetary oscillation method was used. Two of the galaxieswere found to contain scintillating components with angular dimensionsof less than 1 arcsec and flux densities of more than 1 Jy. Theobservations of double galaxies at low radio frequencies indicate thatgalaxies in pairs are more active than single galaxies.
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Some spectrophotometric data for 31 galaxies from Karchentsev's list
The equivalent widths and relative intensities of the emission lines of31 Karachentsev galaxies are determined on spectra obtained with a 5-mtelescope incorporating a 512-channel scanner. The physical conditionsin the nuclei of the galaxies are analyzed and the relative oxygencontent is defined. The parameters derived are compared to similarparameters of Seyfert, Arakelian, and Markarian galaxies.
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Double galaxy investigations. I - Observations
Redshift information from 240 A/mm spectrograms is presented for 370double arcsec galaxy systems from the Karachentsev (1972) catalog,including all pairs in that catalog with separation less than 80 arcsec.An extensive error discussion utilizing internal and external (21 cm)comparisons provides calibration of systematic error and determines theuncertainty for a typical high weight optical redshift to be plus orminus 65 km/sec. Internal differential redshifts within single spectrausing common lines achieve accuracies of 18-30 km/sec, depending uponseparation, and are available for about 200 pairs. Extensive informationon emission and other properties is also provided.
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