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|Cluster analysis of extremely high energy cosmic rays in the northern sky|
The arrival directions of extremely high energy cosmic rays (EHECR)above 4x1019 eV, observed by four surface array experimentsin the northern hemisphere, are examined for coincidences from similardirections in the sky. The total number of cosmic rays is 92. Asignificant number of double coincidences (doublet) and triplecoincidences (triplet) is observed on the supergalactic plane within theexperimental angular resolution. The chance probability of suchmultiplets from a uniform distribution is less than 1% if we consider arestricted region within /+/-10 deg of the supergalactic plane. Thoughthere is still a possibility of chance coincidence, the present resultson small angle clustering along the supergalactic plane may be importantin interpreting EHECR enigma. An independent set of data is required tocheck our claims.
|Bright galaxies from WENSS. I. The minisurvey|
A search for bright galaxies associated with radio sources from theWENSS minisurvey has been carried out. A galaxy counterpart was foundfor 402 of almost 10,000 radio sources. Of these a radio and opticallycomplete sample, with a flux density limit at 325 MHz of 30 mJy and alimiting red magnitude of 16, can be constructed, which contains 119galaxies. This paper is the first step of a more general study, in whichwe aim to derive a bright galaxy sample from the entire WENSS survey(which is now available in the public domain) and thus to constructpractically definitive local radio luminosity functions of ellipticaland spiral galaxies. We briefly describe the WENSS minisurvey, and thesteps that are needed for the optical identification of its radiosources. Due to the large numbers of sources involved (over 200,000)completely automated procedures are obviously needed and we discussthese in some detail. It is shown that with modern utilities projects asdescribed here have become quite feasible. Some results (e.g. apreliminary determination of the local radio luminosity function) arepresented. Table 1 is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (22.214.171.124) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
|Kinematical Observations of a Sample of Binary Galaxies|
|A Spectrophotometric Survey of Merging Galaxies|
We present long-slit spectrophotometry of 40 merging or stronglyinteracting galaxy systems in the wavelength range 3650-7100 A. Alongwith optically selected objects, the sample includes 10 ultraluminousIRAS galaxies with evidence of ongoing merger activity. The data show awide variety of phenomena, with spectra resembling those of isolatedelliptical galaxies, early and late-type spiral galaxies, activegalactic nuclei starbursts, and poststarburst systems.
|Spectrophotometric Properties of Merging Galaxies|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ...450..547L&db_key=AST
|A near-infrared imaging survey of interacting galaxies - The small angular-size ARP systems|
Near-IR images of a large sample of interacting galaxies selected fromthe Atlas of Peculiar Galaxies by Arp (1966) have been obtained.Approximately 180 systems have been imaged in at least two, and usuallythree of the standard JHK bands. The survey and the observing and datareduction procedures, are described, and contour plots and aperturephotometry are presented. Future papers will analyze the imaging data bygroupings based on interaction type, stage, and progenitors. The goalsof the analysis are to explore the relationships between galaxyinteractions, activity, and morphology by studying the structure of thenear-IR luminosity distribution, where extinction effects are muchreduced relative to the optical and the major stellar mass component ofgalaxies dominates the observed light.
|Relative velocities of dumbbell galaxies|
A systematic study of a morphologically-selected sample of dumbbellgalaxies is presented. A dumbbell/multiple nuclei subclassificationscheme is introduced. The single-object velocity dispersion of dumbbellcomponents in Abell-type clusters is 436 + or - 88 km/sec, which issignificantly smaller than that of normal cluster galaxies and ofmultiple nuclei systems. A detailed analysis of this sample, taking intoaccount various projection effects, indicates that the two components ofdumbbell pairs are physically associated, and probably in circularorbits around a common center. A relative rotation velocity of 1200km/sec at a separation of 40 kpc is indicated. This translates into asingle-object velocity of 600 km, intermediate between the typicalrotation velocity in the central part of a cD galaxy and that in thecluster-at-large. Furthermore, the rotation curve appears to be risingin this radial range. The data provide direct evidence of the existenceof a dark intracluster medium on a scale of 20-50 kpc.
|The nuclear activity of interacting galaxies|
A search for active galactic nuclei among interacting galaxies isreported. A sample of 167 systems of interacting and asymmetric galaxieswas observed spectrophotometrically in the spectral range 4700-7100 A.The results are compared with a sample of isolated galaxies. It is foundthat (1) there are no Seyfert nuclei in elliptical or dwarf irregulargalaxies of the sample; (2) there is an excess of Seyfert nuclei amonginteracting spirals, but it is only at the 90 percent confidence level;(3) this excess becomes statistically significant (98 percent) when onlystrongly interacting spirals are included (four new Seyfert nuclei arepresented); (4) in the subgroup of galaxies with extreme tidaldistortions, no Seyfert nuclei were found.
|A 21 centimeter line survey of a complete sample of interacting and isolated galaxies|
The paper presents 21 cm line observations of a complete sample ofinteracting and isolated galaxies made with the National Radio AstronomyObservatory 91 and 43 m telescopes and the Arecibo 3035 m telescope. The21 cm line data are combined with a homogeneous set of optical data onangular diameters, axial ratios, magnitudes, and colors, and integralproperties are calculated for the galaxies in both samples. In thispaper, the sample selection procedures, the method of observation, thedata reduction, and the observational errors are described. Thedetection percentages are presented for both samples.
|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.
|Atlas of Peculiar Galaxies|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1966ApJS...14....1A&db_key=AST
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