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Galaxy interactions - poor starburst triggers. III. A study of a complete sample of interacting galaxies
We report on a study of tidally triggered star formation in galaxiesbased on spectroscopic/photometric observations in the optical/near-IRof a magnitude limited sample of 59 systems of interacting and merginggalaxies and a comparison sample of 38 normal isolated galaxies. From astatistical point of view the sample gives us a unique opportunity totrace the effects of tidally induced star formation. In contrast toresults from previous investigations, our global UBV colours do notsupport a significant enhancement of starforming activity in theinteracting/merging galaxies. We also show that, contrary to previousclaims, there is no significantly increased scatter in the colours ofArp galaxies as compared to normal galaxies. We do find support formoderate (a factor of ~ 2-3) increase in star formation in the verycentres of the interacting galaxies of our sample, contributingmarginally to the total luminosity. The interacting and in particularthe merging galaxies are characterized by increased far infrared(hereafter FIR) luminosities and temperatures that weakly correlate withthe central activity. The LFIR/LB ratio however,is remarkably similar in the two samples, indicating that truestarbursts normally are not hiding in the central regions of the FIRluminous cases. The gas mass-to-luminosity ratio in optical-IR ispractically independent of luminosity, lending further support to thepaucity of true massive starburst galaxies triggered byinteractions/mergers. We estimate the frequency of such cases to be ofthe order of ~ 0.1% of the galaxies in an apparent magnitude limitedsample. Our conclusion is that interacting and merging galaxies, fromthe global star formation aspect, generally do not differ dramaticallyfrom scaled up versions of normal, isolated galaxies. No drastic changewith redshift is expected. One consequence is that galaxy formationprobably continued over a long period of time and did not peak at aspecific redshift. The effects of massive starbursts, like blowoutscaused by superwinds and cosmic reionization caused by starburstpopulations would also be less important than what is normally assumed.Based on observations collected at the European Southern Observatory, LaSilla, Chile.
| Total magnitude, radius, colour indices, colour gradients and photometric type of galaxies
We present a catalogue of aperture photometry of galaxies, in UBVRI,assembled from three different origins: (i) an update of the catalogueof Buta et al. (1995) (ii) published photometric profiles and (iii)aperture photometry performed on CCD images. We explored different setsof growth curves to fit these data: (i) The Sersic law, (ii) The net ofgrowth curves used for the preparation of the RC3 and (iii) A linearinterpolation between the de Vaucouleurs (r(1/4) ) and exponential laws.Finally we adopted the latter solution. Fitting these growth curves, wederive (1) the total magnitude, (2) the effective radius, (3) the colourindices and (4) gradients and (5) the photometric type of 5169 galaxies.The photometric type is defined to statistically match the revisedmorphologic type and parametrizes the shape of the growth curve. It iscoded from -9, for very concentrated galaxies, to +10, for diffusegalaxies. Based in part on observations collected at the Haute-ProvenceObservatory.
| CO and HI in a southern sample of interacting galaxies. I. The data
Using SEST, the Parkes antenna and the Australia Telescope CompactArray, we have made a survey of the ^12CO(1-0) and HI emission of anoptically-selected sample of ~60 southern interacting and merginggalaxies. In this paper we present the data and determine global massesof neutral gas (in molecular and atomic form) for the observed galaxies.We have detected HI in 26 systems and found that these galaxies haveless than 15% of their gas in molecular form. Figure 3 in its entirelyis only available in electronic form at CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| The Catalog of Southern Ringed Galaxies
The Catalog of Southern Ringed Galaxies (CSRG) is a comprehensivecompilation of diameters, axis ratios, relative bar position angles, andmorphologies of inner and outer rings, pseudorings, and lenses in 3692galaxies south of declination -17 deg. The purpose of the catalog is toevaluate the idea that these ring phenomena are related to orbitalresonances with a bar or oval in galaxy potentials. The catalog is basedon visual inspection of most of the 606 fields of the Science ResearchCouncil (SRC) IIIa-J southern sky survey, with the ESO-B, ESO-R, andPalomar Sky surveys used as auxiliaries when needed for overexposed coreregions. The catalog is most complete for SRC fields 1-303 (mostly southof declination -42 deg). In addition to ringed galaxies, a list of 859mostly nonringed galaxies intended for comparison with other catalogs isprovided. Other findings from the CSRG that are not based on statisticsare the identification of intrinsic bar/ring misalignment; bars whichunderfill inner rings; dimpling of R'1pseudorings; pointy, rectangular, or hexagonal inner or outer ringshapes; a peculiar polar-ring-related system; and other extreme examplesof spiral structure and ring morphology.
| A study of a complete sample of interacting galaxies. II. Images, colour distributions and spectra.
We present broadband images, two-colour maps and spectra of a magnitudelimited sample of interacting and merging galaxies.
| Fine structure in the early-type components in mixed pairs of galaxies.
Not Available
| 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.
| Southern Sky Redshift Survey - The catalog
The catalog of radial velocities for galaxies which comprise thediameter-limited sample of the Southern Sky Redshift Survey ispresented. It consolidates the data of observations carried out at theLas Campanas Observatory, Observatorio Nacional, and South AfricanAstronomical Observatory. The criteria used for the sample selection aredescribed, as well as the observational procedures and the techniqueutilized to obtain the final radial velocities. The intercomparisonbetween radial velocity measurements from different telescopes indicatesthat the final data base is fairly homogeneous with a typical error ofabout 40 km/s. The sample is at present 90 percent complete, and themissing galaxies are predominantly objects with very low surfacebrightness for which it is very difficult to obtain optical redshifts.
| A study of a complete sample of interacting galaxies. I - Presentation of the sample and the UBVRIJHK photometry
An investigation is presented on what effects galaxy-galaxy interactionhas on the properties of the involved galaxies. A magnitude limitedsample of interacting galaxies is presented, together with a controlsample of isolated galaxies. The Cousins UBVRI and Johnson JHKphotometry of all galaxies included in the samples is also presented.
| Southern Galaxy Catalogue.
Not Available
| A List of Peculiar Galaxies, Interacting Pairs, Groups and Clusters South of Declination -43°
The coordinates, dimensions and short descriptions of 186 objects aregiven after a search of the Maksutov plate collection in theObservatorio Astronómico, Universidad de Chile, Santiago
| Corrections to the Reference Catalogue of Bright Galaxies (Third List)
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972PASP...84..462C&db_key=AST
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