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An X-Ray Atlas of Groups of Galaxies
A search was conducted for a hot intragroup medium in 109 low-redshiftgalaxy groups observed with the ROSAT PSPC. Evidence for diffuse,extended X-ray emission is found in at least 61 groups. Approximatelyone-third of these detections have not been previously reported in theliterature. Most of the groups are detected out to less than half of thevirial radius with ROSAT. Although some spiral-rich groups do contain anintragroup medium, diffuse emission is restricted to groups that containat least one early-type galaxy.
| Tidally Triggered Star Formation in Close Pairs of Galaxies. II. Constraints on Burst Strengths and Ages
Galaxy-galaxy interactions rearrange the baryons in galaxies and triggersubstantial star formation; the aggregate effects of these interactionson the evolutionary histories of galaxies in the universe are poorlyunderstood. We combine B- and R-band photometry and optical spectroscopyto estimate the strengths and timescales of bursts of triggered starformation in the centers of 190 galaxies in pairs and compact groups.Based on an analysis of the measured colors and EW(Hα), wecharacterize the preexisting and triggered populations separately. Thebest-fitting burst scenarios assume stronger reddening corrections forline emission than for the continuum and continuous star formationlasting for >~100 Myr. The most realistic scenarios require aninitial mass function that is deficient in the highest mass stars. Thecolor of the preexisting stellar population is the most significantsource of uncertainty. Triggered star formation contributessubstantially (probably >~50%) to the R-band flux in the centralregions of several galaxies; tidal tails do not necessarily accompanythis star formation. Many of the galaxies in our sample have bluercenters than outskirts, suggesting that pre- or nonmerger interactionsmay lead to evolution along the Hubble sequence. These objects wouldappear blue and compact at higher redshifts; the older, redder outskirtsof the disks would be difficult to detect. Our data indicate thatgalaxies with larger separations on the sky contain weaker, and probablyolder, bursts of star formation on average. However, confirmation ofthese trends requires further constraints on the colors of the olderstellar populations and on the reddening for individual galaxies.
| The UZC-SSRS2 Group Catalog
We apply a friends-of-friends algorithm to the combined Updated ZwickyCatalog and Southern Sky Redshift Survey to construct a catalog of 1168groups of galaxies; 411 of these groups have five or more members withinthe redshift survey. The group catalog covers 4.69 sr, and all groupsexceed the number density contrast threshold, δρ/ρ=80. Wedemonstrate that the groups catalog is homogeneous across the twounderlying redshift surveys; the catalog of groups and their membersthus provides a basis for other statistical studies of the large-scaledistribution of groups and their physical properties. The medianphysical properties of the groups are similar to those for groupsderived from independent surveys, including the ESO Key Programme andthe Las Campanas Redshift Survey. We include tables of groups and theirmembers.
| Compact groups in the UZC galaxy sample
Applying an automatic neighbour search algorithm to the 3D UZC galaxycatalogue (Falco et al. \cite{Falco}) we have identified 291 compactgroups (CGs) with radial velocity between 1000 and 10 000 kms-1. The sample is analysed to investigate whether Tripletsdisplay kinematical and morphological characteristics similar to higherorder CGs (Multiplets). It is found that Triplets constitute lowvelocity dispersion structures, have a gas-rich galaxy population andare typically retrieved in sparse environments. Conversely Multipletsshow higher velocity dispersion, include few gas-rich members and aregenerally embedded structures. Evidence hence emerges indicating thatTriplets and Multiplets, though sharing a common scale, correspond todifferent galaxy systems. Triplets are typically field structures whilstMultiplets are mainly subclumps (either temporarily projected orcollapsing) within larger structures. Simulations show that selectioneffects can only partially account for differences, but significantcontamination of Triplets by field galaxy interlopers could eventuallyinduce the observed dependences on multiplicity. Tables 1 and 2 are onlyavailable in electronic at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.125.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/391/35
| Supernovae in isolated galaxies, in pairs and in groups of galaxies
In order to investigate the influence of environment on supernova (SN)production, we have performed a statistical investigation of the SNediscovered in isolated galaxies, in pairs and in groups of galaxies. 22SNe in 18 isolated galaxies, 48 SNe in 40 galaxy members of 37 pairs and211 SNe in 170 galaxy members of 116 groups have been selected andstudied. We found that the radial distributions of core-collapse SNe ingalaxies located in different environments are similar, and consistentwith those reported by Bartunov, Makarova & Tsvetkov. SNe discoveredin pairs do not favour a particular direction with respect to thecompanion galaxy. Also, the azimuthal distributions inside the hostmembers of galaxy groups are consistent with being isotropics. The factthat SNe are more frequent in the brighter components of the pairs andgroups is expected from the dependence of the SN rates on the galaxyluminosity. There is an indication that the SN rate is higher in galaxypairs compared with that in groups. This can be related to the enhancedstar formation rate in strongly interacting systems. It is concludedthat, with the possible exception of strongly interacting systems, theparent galaxy environment has no direct influence on SN production.
| The Tully-Fisher Relation as a Measure of Luminosity Evolution: A Low-Redshift Baseline for Evolving Galaxies
We use optical rotation curves to investigate the R-band Tully-Fisherproperties of a sample of 90 spiral galaxies in close pairs, covering arange of luminosities, morphological types, and degrees of tidaldistortion. The galaxies follow the Tully-Fisher relation remarkablywell, with the exception of eight distinct ~3 σ outliers. Althoughmost of the outliers show signs of recent star formation, gasdynamicaleffects are probably the dominant cause of their anomalous Tully-Fisherproperties. Four outliers with small emission-line widths have verycentrally concentrated line emission and truncated rotation curves; thecentral emission indicates recent gas infall after a close galaxy-galaxypass. These four galaxies may be local counterparts to compact, bluegalaxies at intermediate redshift. The remaining galaxies have anegligible offset from the reference Tully-Fisher relation, but ashallower slope (2.6 σ significance) and a 25% larger scatter. Weargue that triggered star formation is a significant contributor to theslope difference. We characterize the nonoutlier sample with measures ofdistortion and star formation to search for third-parameter dependencein the residuals of the TF relation. Severe kinematic distortion is theonly significant predictor of TF residuals; this distortion is not,however, responsible for the slope difference from the referencedistribution. Because the outliers are easily removed by sigma clipping,we conclude that even in the presence of some tidal distortion,detection of moderate (>~0.5 mag in rest-frame R) luminosityevolution should be possible with high-redshift samples the size of this90-galaxy study. The slope of the TF relation, although difficult tomeasure, is as fundamental for quantifying luminosity evolution as thezero-point offset. Some observations reported in this paper wereobtained at the Multiple Mirror Telescope Observatory, a facilityoperated jointly by the University of Arizona and the SmithsonianInstitution.
| The intragroup medium in loose groups of galaxies
We have used the ROSAT PSPC to study the properties of a sample of 24X-ray-bright galaxy groups, representing the largest sample examined indetail to date. Hot plasma models are fitted to the spectral data toderive temperatures, and modified King models are used to characterizethe surface brightness profiles. In agreement with previous work, wefind evidence for the presence of two components in the surfacebrightness profiles. The extended component is generally found to bemuch flatter than that observed in galaxy clusters, and there isevidence that the profiles follow a trend with system mass. We deriverelationships between X-ray luminosity, temperature and optical velocitydispersion. The relation between X-ray luminosity and temperature isfound to be LX~T4.9, which is significantlysteeper than the same relation in galaxy clusters. These results are ingood agreement with pre-heating models, in which galaxy winds raise theinternal energy of the gas, inhibiting its collapse into the shallowpotential wells of poor systems.
| Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
In this paper we describe the Nearby Optical Galaxy (NOG) sample, whichis a complete, distance-limited (cz<=6000 km s-1) andmagnitude-limited (B<=14) sample of ~7000 optical galaxies. Thesample covers 2/3 (8.27 sr) of the sky (|b|>20deg) andappears to have a good completeness in redshift (97%). We select thesample on the basis of homogenized corrected total blue magnitudes inorder to minimize systematic effects in galaxy sampling. We identify thegroups in this sample by means of both the hierarchical and thepercolation ``friends-of-friends'' methods. The resulting catalogs ofloose groups appear to be similar and are among the largest catalogs ofgroups currently available. Most of the NOG galaxies (~60%) are found tobe members of galaxy pairs (~580 pairs for a total of ~15% of objects)or groups with at least three members (~500 groups for a total of ~45%of objects). About 40% of galaxies are left ungrouped (field galaxies).We illustrate the main features of the NOG galaxy distribution. Comparedto previous optical and IRAS galaxy samples, the NOG provides a densersampling of the galaxy distribution in the nearby universe. Given itslarge sky coverage, the identification of groups, and its high-densitysampling, the NOG is suited to the analysis of the galaxy density fieldof the nearby universe, especially on small scales.
| Arcsecond Positions of UGC Galaxies
We present accurate B1950 and J2000 positions for all confirmed galaxiesin the Uppsala General Catalog (UGC). The positions were measuredvisually from Digitized Sky Survey images with rms uncertaintiesσ<=[(1.2")2+(θ/100)2]1/2,where θ is the major-axis diameter. We compared each galaxymeasured with the original UGC description to ensure high reliability.The full position list is available in the electronic version only.
| The I-Band Tully-Fisher Relation for SC Galaxies: 21 Centimeter H I Line Data
A compilation of 21 cm line spectral parameters specifically designedfor application of the Tully-Fisher (TF) distance method is presentedfor 1201 spiral galaxies, primarily field Sc galaxies, for which opticalI-band photometric imaging is also available. New H I line spectra havebeen obtained for 881 galaxies. For an additional 320 galaxies, spectraavailable in a digital archive have been reexamined to allow applicationof a single algorithm for the derivation of the TF velocity widthparameter. A velocity width algorithm is used that provides a robustmeasurement of rotational velocity and permits an estimate of the erroron that width taking into account the effects of instrumental broadeningand signal-to-noise. The digital data are used to establish regressionrelations between measurements of velocity widths using other commonprescriptions so that comparable widths can be derived throughconversion of values published in the literature. The uniform H I linewidths presented here provide the rotational velocity measurement to beused in deriving peculiar velocities via the TF method.
| A Dual-Transition Survey of CO in the Coma Cluster of Galaxies
We present CO (1-0) and (2-1) observations of 33 galaxies in theComa/Abell 1367 supercluster made with the IRAM 30 m telescope. Inaddition, we observed four of the galaxies with the 15 m JCMT, at CO(2-1). The indicative molecular gas mass correlates strongly with thedust mass, and a stronger relationship is seen between the far-infraredand CO surface brightnesses than between the simple luminosities.Comparison of CO (2-1) spectra from IRAM and JCMT allows an estimate ofthe size of the CO emission region, which varies between 10% and 100% ofthe size of the optical disk, contrary to earlier estimates that the COis contained within the optical half-light radius. There is a slightsuggestion that starburst galaxies have a lower ratio of brightnesstemperatures, T_b(2-1)/T_b(1-0), than other galaxies.
| 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.
| The 3-D structure of the Coma-A 1367 supercluster: Optical spectroscopy of 102 galaxies
Optical spectroscopy of 117 CGCG galaxies, 102 of which are projected inthe direction of the Coma-A 1367 supercluster, is reported. These newmeasurements, added to those found in the literature, bring to 1068 thenumber of CGCG galaxies in this region with available redshift, out of atotal of 1085 objects with m_p<= 15.7. We use these data to infer the3-D structure of the Coma supercluster. Based on observations obtainedwith the Loiano telescope belonging to the University of Bologna, Italy,and with the G. Haro telescope of the INAOE, Mexico.
| On the local radio luminosity function of galaxies. II. Environmental dependences among late-type galaxies
Using new extensive radio continuum surveys at 1.4 GHz (FIRST and NVSS),we derive the distribution of the radio/optical and radio/NIR luminosity(RLF) of late-type (Sa-Irr) galaxies (m_p<15.7) in 5 nearby clustersof galaxies: A262, Cancer, A1367, Coma and Virgo. With the aim ofdiscussing possible environmental dependences of the radio properties,we compare these results with those obtained for relatively isolatedobjects in the Coma supercluster. We find that the RLF of Cancer, A262and Virgo are consistent with that of isolated galaxies. Conversely weconfirm earlier claims that galaxies in A1367 and Coma have their radioemissivity enhanced by a factor ~ 5 with respect to isolated objects. Wediscuss this result in the framework of the dynamical pressure sufferedby galaxies in motion through the intra-cluster gas (ram-pressure). Wefind that the radio excess is statistically larger for galaxies in fasttransit motion. This is coherent with the idea that enhanced radiocontinuum activity is associated with magnetic field compression. TheX-ray luminosities and temperatures of Coma and A1367 imply that thesetwo clusters have significantly larger intracluster gas density than theremaining three studied ones, providing a clue for explaining the higherradio continuum luminosities of their galaxies. Multiple systems in theComa supercluster bridge (with projected separations smaller than 300kpc) have radio luminosities significantly larger than isolatedgalaxies. Table~1 is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html}
| Groups of galaxies. III. Some empirical characteristics.
Not Available
| Environments of Redshift Survey Compact Groups of Galaxies
Redshift survey compact groups (RSCGs) are tight knots of N >= 3galaxies selected from the CfA2+SSRS2 redshift survey. The selection isbased on physical extent and association in redshift space alone. Wemeasured 300 new redshifts of fainter galaxies within 1 h^-1 Mpc of 14RSCGs to explore the relationship between RSCGs and their environments.Thirteen of 14 RSCGs are embedded in overdense regions of redshiftspace. The systems range from a loose group of five members to an Abellcluster. The remaining group, RSCG 64, appears isolated. RSCGs areisolated and distinct from their surroundings to varying degrees, as arethe Hickson compact groups. Among the 13 embedded RSCGs, three aredistinct from their general environments (RSCG 9, RSCG 11, and RSCG 85).
| 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.
| Testing the physical reality of binaries and compact groups. Properties of early-type galaxies in groups with diffuse X-ray emission
We present data on the stellar kinematics of the brightest ellipticalsin HCG 62, HCG 68, NGC 2300 groups. Moreover, we report on ASCA GIS aswell as optical observations of the early-type member of the pair K 416(NGC 5480/5481) similar, in many respects, to the dominant pair in theNGC 2300 group. The kinematics of HCG 62a/b and HCG 68a/b indicate thatthey are not interacting pairs. HCG 62a is instead possibly interactingwith HCG 62c, as suggested by their morphology (see Mendes de Oliveiraand Hickson 1994), In contrast to the results for the NGC 2300/2276group, ASCA observations indicate a significant absence of hot gas inthe K 416 system. Whether the NGC 2300 multiplet is viewed as a loosegroup or as a massive E+S pair, it is clear that similar morphologicalentities do not always show similar X-ray properties. Under thehypothesis that diffuse X-ray emission marks the group potential, weconsider the possibility that K 416 is an unbound encounter. In thisscenario, morphological distortions are indicative of the ongoinginteraction, but are only circumstantially correlated with the physicalreality of a pair/multiplet as a bound system. Based on observationsobtained at 1.93m telescope of Observatoire de Haute Provence operatedby INSU.
| Galaxies with a UV excess in which supernovae have been observed.
Not Available
| Early spectra of the supernova 1987F
Spectroscopy is presented of the peculiar Type II supernova 1987F,sometimes called the `Type I Seyfert imposter'. This supernova differedfrom others of Type II in the slow evolution in its light curve and thestrengths and profiles of the spectral lines. The time covered is 1987April 2 to June 8, when the spectrum of the supernova evolved from asimple nearly featureless blue continuum with superimposed narrowemission lines of HI, HeI, [NII], [OIII], and [SII] to a complicatedcombination of broad and narrow emission components in HI and HeI plusthe wide features identified by earlier authors as being caused by FeII.Using a simple model of an expanding spherical shell with absorption forthe broad Hα and Hβ lines, an expansion speed of ~8000 kms^-1 is estimated for the outer surface of the shell. This expansionvelocity, combined with the mean density of the shell derived threeways, predicts a mass of ~0.2 M_ for the ejected hydrogen above thephotosphere. The He abundance appears to be enhanced in this object. Theunusual light curve indicates a total luminous energy of ~10^51 erg.After 50d, its shape can be fitted either by a model using a shockwaveexpanding into circumstellar material, by 56Ni-->56Co-->^56Fedecay with a reddening and radiative transfer dependent mass of 0.8 to2.6 M_ for the ^56Ni, or both. Such a high amount of ^56Ni suggests thatother mechanisms are involved. Possible processes leading to SN 1987Fare explored and the suggested link between this object and AGNs is alsobriefly discussed.
| The Intragroup Medium in Poor Groups of Galaxies
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJ...456...80M&db_key=AST
| On the question of radio emission of spiral galaxies in groups of galaxies
It has been shown that the radio emission properties of spiral galaxies,if the other conditions are the same, are determined rather by thepresence of the close neighbours than by space density of galaxiesaround them. The rate of occurence of radio sources and their radioluminosities among the spiral members of groups of galaxies depend onthe projected seperation between them and their nearest neighbour. Theshorter this seperation the higher the probability of radio emission.
| Type "IIn" Supernovae: A Search for Radio Emission
We have conducted a search using the Very Large Array for radio emissionfrom members of Schlegel's (1990) proposed supernova subclass, Type IIn,which show optical characteristics indicative of shock interaction withdense circumstellar matter. None has been detected to upper limits of<~ 0.2 mJy. We compare the corresponding radio luminosity upperlimits for these supernovae to the radio luminosities for known Type Mradio supernovae. Although broadly similar optically to the unusual TypeIIn SNs 1988Z and 1986J, none of the observed supernovae could be nearlyas radio luminous. We find that the radio behavior of most Type IInsupernovae may not be significantly different from that of other morenormal Type II supernovae. It therefore appears that optical spectraalone are not sufficient to predict radio luminosity and thatintrinsically radio luminous supernovae, such as SNs 1988Z and 1986J,are quite rare.
| 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.
| A ^12^CO(1-0) survey of spiral galaxies in the region of the Coma supercluster.
We present observations of the ^12^CO(J=1-0) line at 2.6mm of 65galaxies located in the Coma supercluster region: 33 actually belong tothe Coma supercluster while 32 are either foreground or backgroundobjects. These data have been obtained using the NRAO 12m telescope atKitt Peak (United States), and for four galaxies, using the IRAM 30mtelescope at Pico Veleta (Spain). Out of these 65 galaxies, 54 had neverbeen observed in the CO(1-0) line; 49 have been detected by us, of which37 are new detections. We give molecular gas masses deduced from the COline integrated intensities, and upper limits for the 16 undetectedobjects, computed with a Galactic conversion factorN(H_2_)=2.3x10^20^I(CO) and H_0_=75km/s/Mpc.
| Automated surface photometry for the Coma Cluster galaxies: The catalog
A homogeneous photometry catalog is presented for 450 galaxies withB25.5 less than or equal to 16 mag located in the 9.8 deg x9.8 deg region centered on the Coma Cluster. The catalog is based onphotographic photometry using an automated surface photometry softwarefor data reduction applied to B-band Schmidt plates. The catalogprovides accurate positions, isophotal and total magnitudes, major andminor axes, and a few other photometric parameters including rudimentarymorphology (early of late type).
| A Study of Ultraviolet Objects near the North Galactic Pole with FAUST
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ...450..137B&db_key=AST
| Galaxy Properties at the North Galactic Pole. I. Photometric Properties on Large Spatial Scales
A two-color study of the galaxies detected on POSS-I in a 289 squaredegree region centered on the North Galactic Pole is presented. We use avariety of mapping techniques to characterize the large-scale spatialdistribution of galaxies. The depth and sample size of this new surveyallows, for the first time, the isolation of large photometricsubsamples of galaxies in high- and low-density environments on thescale of superclusters. Our principal finding is a statisticallysignificant difference between the mean photometric properties of thesesubsamples in the sense that galaxies in the high-density Coma andfilament environments have redder colors and larger concentrationindices than galaxies drawn from low-density interfilament regions.These results are in accord with the known morphology-density relation.Thus, appropriately chosen photometric and morphological parameters, inconcert with a galaxy surface density map, can be used to selectstructures from the projected galaxy distribution which correspond toregions of high density. An illustration of this point is our discoveryof a concentration of blue galaxies identified in our maps near the coreof the Coma cluster. This feature is comprised of early-type galaxieswhich exhibit signs of current or recent star formation. These resultsare predicated on relations between morphological type and photometricparameters derived from APS scans of POSS-I. We therefore discuss theimage calibration procedures used to compile our catalog of physicallysignificant photometric parameters. We demonstrate the morphologicaltype dependence among quantities such as mean color and imageconcentration index, and the lack of such a dependence for mean surfacebrightness.
| The spatial distribution of supernovae in paired and interacting galaxies
In order to investigate the location of supernovae (SNe) in paired andinteracting galaxies, the 54 supernovae discovered up to May 1993 in 14Isolated Pairs of Galaxies and the 32 Interacting Systems were taken asa sample and studied. The whole sample of SNe, as well as a subsampleformed of type II, and Ib SNe, whose progenitors are young massivestars, do not appear in any one particluar direction with respect to thecompanion. On paired and interacting galaxies, the radial distributionof type Ib and II SNe peaks more toward the galaxy centers than it doesin isolated galaxies, indicating an enhanced Star Formation Rate (SFR)around the nuclei and in the inner disks. The distribution of SNIaappear similar in both samples, confirming that their progenitors arenot the same as those of SNII and IB. The SN rates are related to galaxyluminosity and, as expected, the discovery of SNe is twice more frequentin the brighter galaxy of the pair than in fainter ones. We did not findany relation between the locations of SNe in parent galaxies, the totalStar Formation activity and the kinematics of paired and interactinggalaxies.
| Distribution of supernovae relative to spiral arms and H II regions
We have studied the association of supernovae in spiral galaxies withsites of recent stars formation -- sprial arms and H II regions. It isshown that supernovae (SNe) of Types Ia, Ib, and II exhibitconcentration to spiral arms and their distributions over the distanceto the nearest spiral arm do not differ significantly. This result isconfirmed by a Kolmogorov-Smirnov test comparison with the distancedistributions, expected if SNe are distributed randomly inside the modelgalaxy. SNe of types Ib and II show a strong concentration towards H IIregions, while distribution of SNe Ia can be explained by chancesuperposition. All studied distributions of SNe Ib and II show strikingsimilarity, which suggests that their progenitors are massive stars withsimilar ages and initial masses. The association of SNe Ia with spiralarms suggests that their progenitors in spiral galaxies are likely to beintermediate mass stars.
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