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The Survey for Ionization in Neutral Gas Galaxies. I. Description and Initial Results
We introduce the Survey for Ionization in Neutral Gas Galaxies (SINGG),a census of star formation in H I-selected galaxies. The survey consistsof Hα and R-band imaging of a sample of 468 galaxies selected fromthe H I Parkes All Sky Survey (HIPASS). The sample spans three decadesin H I mass and is free of many of the biases that affect otherstar-forming galaxy samples. We present the criteria for sampleselection, list the entire sample, discuss our observational techniques,and describe the data reduction and calibration methods. This paperfocuses on 93 SINGG targets whose observations have been fully reducedand analyzed to date. The majority of these show a single emission linegalaxy (ELG). We see multiple ELGs in 13 fields, with up to four ELGs ina single field. All of the targets in this sample are detected inHα, indicating that dormant (non-star-forming) galaxies withMHI>~3×107 Msolar are veryrare. A database of the measured global properties of the ELGs ispresented. The ELG sample spans 4 orders of magnitude in luminosity(Hα and R band), and Hα surface brightness, nearly 3 ordersof magnitude in R surface brightness and nearly 2 orders of magnitude inHα equivalent width (EW). The surface brightness distribution ofour sample is broader than that of the Sloan Digital Sky Survey (SDSS)spectroscopic sample, the EW distribution is broader than prism-selectedsamples, and the morphologies found include all common types ofstar-forming galaxies (e.g., irregular, spiral, blue compact dwarf,starbursts, merging and colliding systems, and even residual starformation in S0 and Sa spirals). Thus, SINGG presents a superior censusof star formation in the local universe suitable for further studiesranging from the analysis of H II regions to determination of the localcosmic star formation rate density.
| Ultraluminous X-Ray Sources in Nearby Galaxies from ROSAT High Resolution Imager Observations I. Data Analysis
X-ray observations have revealed in other galaxies a class ofextranuclear X-ray point sources with X-ray luminosities of1039-1041 ergs s-1, exceeding theEddington luminosity for stellar mass X-ray binaries. Theseultraluminous X-ray sources (ULXs) may be powered by intermediate-massblack holes of a few thousand Msolar or stellar mass blackholes with special radiation processes. In this paper, we present asurvey of ULXs in 313 nearby galaxies withD25>1' within 40 Mpc with 467 ROSAT HighResolution Imager (HRI) archival observations. The HRI observations arereduced with uniform procedures, refined by simulations that help definethe point source detection algorithm employed in this survey. A sampleof 562 extragalactic X-ray point sources withLX=1038-1043 ergs s-1 isextracted from 173 survey galaxies, including 106 ULX candidates withinthe D25 isophotes of 63 galaxies and 110 ULX candidatesbetween 1D25 and 2D25 of 64 galaxies, from which aclean sample of 109 ULXs is constructed to minimize the contaminationfrom foreground or background objects. The strong connection betweenULXs and star formation is confirmed based on the striking preference ofULXs to occur in late-type galaxies, especially in star-forming regionssuch as spiral arms. ULXs are variable on timescales over days to yearsand exhibit a variety of long term variability patterns. Theidentifications of ULXs in the clean sample show some ULXs identified assupernovae (remnants), H II regions/nebulae, or young massive stars instar-forming regions, and a few other ULXs identified as old globularclusters. In a subsequent paper, the statistic properties of the surveywill be studied to calculate the occurrence frequencies and luminosityfunctions for ULXs in different types of galaxies to shed light on thenature of these enigmatic sources.
| The 1000 Brightest HIPASS Galaxies: H I Properties
We present the HIPASS Bright Galaxy Catalog (BGC), which contains the1000 H I brightest galaxies in the southern sky as obtained from the H IParkes All-Sky Survey (HIPASS). The selection of the brightest sourcesis based on their H I peak flux density (Speak>~116 mJy)as measured from the spatially integrated HIPASS spectrum. The derived HI masses range from ~107 to 4×1010Msolar. While the BGC (z<0.03) is complete inSpeak, only a subset of ~500 sources can be consideredcomplete in integrated H I flux density (FHI>~25 Jy kms-1). The HIPASS BGC contains a total of 158 new redshifts.These belong to 91 new sources for which no optical or infraredcounterparts have previously been cataloged, an additional 51 galaxiesfor which no redshifts were previously known, and 16 galaxies for whichthe cataloged optical velocities disagree. Of the 91 newly cataloged BGCsources, only four are definite H I clouds: while three are likelyMagellanic debris with velocities around 400 km s-1, one is atidal cloud associated with the NGC 2442 galaxy group. The remaining 87new BGC sources, the majority of which lie in the zone of avoidance,appear to be galaxies. We identified optical counterparts to all but oneof the 30 new galaxies at Galactic latitudes |b|>10deg.Therefore, the BGC yields no evidence for a population of``free-floating'' intergalactic H I clouds without associated opticalcounterparts. HIPASS provides a clear view of the local large-scalestructure. The dominant features in the sky distribution of the BGC arethe Supergalactic Plane and the Local Void. In addition, one can clearlysee the Centaurus Wall, which connects via the Hydra and Antlia Clustersto the Puppis Filament. Some previously hardly noticable galaxy groupsstand out quite distinctly in the H I sky distribution. Several newstructures, including some not behind the Milky Way, are seen for thefirst time.
| Oxygen and nitrogen abundances in nearby galaxies. Correlations between oxygen abundance and macroscopic properties
We performed a compilation of more than 1000 published spectra of H IIregions in spiral galaxies. The oxygen and nitrogen abundances in each HII region were recomputed in a homogeneous way, using the P-method. Theradial distributions of oxygen and nitrogen abundances were derived. Thecorrelations between oxygen abundance and macroscopic properties areexamined. We found that the oxygen abundance in spiral galaxiescorrelates with its luminosity, rotation velocity, and morphologicaltype: the correlation with the rotation velocity may be slightlytighter. There is a significant difference between theluminosity-metallicity relationship obtained here and that based on theoxygen abundances determined through the R23-calibrations.The oxygen abundance of NGC 5457 recently determined using directmeasurements of Te (Kennicutt et al. \cite{Kennicutt2003})agrees with the luminosity-metallicity relationship derived in thispaper, but is in conflict with the luminosity-metallicity relationshipderived with the R23-based oxygen abundances. The obtainedluminosity-metallicity relation for spiral galaxies is compared to thatfor irregular galaxies. Our sample of galaxies shows evidence that theslope of the O/H - MB relationship for spirals (-0.079± 0.018) is slightly more shallow than that for irregulargalaxies (-0.139 ± 0.011). The effective oxygen yields wereestimated for spiral and irregular galaxies. The effective oxygen yieldincreases with increasing luminosity from MB -11 toMB -18 (or with increasing rotation velocity fromVrot 10 km s-1 to Vrot 100km s-1) and then remains approximately constant. Irregulargalaxies from our sample have effective oxygen yields lowered by afactor of 3 at maximum, i.e. irregular galaxies usually keep at least1/3 of the oxygen they manufactured during their evolution.Appendix, Tables \ref{table:refero}, \ref{table:referV}, and Figs.\ref{figure:sample2}-\ref{figure:sample5} are only available inelectronic form at http://www.edpsciences.org}
| Parkes H I observations of galaxies behind the southern Milky Way. I. The Hydra/Antlia region (l~ 266o to 296o)
As part of our program to map the large-scale distribution of galaxiesbehind the Milky Way, we used the Parkes 210 ft (64 m) radio telescopefor pointed \normalsize H \footnotesize I observations of a sample oflow surface-brightness (due to heavy obscuration) spiral galaxiesselected from the deep optical Zone of Avoidance (ZOA) galaxy catalog inthe Hydra/Antlia region (Kraan-Korteweg \cite{Kraan-2000a}). Searching asimultaneous velocity range of either 300 to 5500 km s-1 or300 to 10 500 km s-1 to an rms level of typically 2-4 m Jyresulted in detections in 61 of the 139 pointings, leading to a total of66 detections (an additional detection was made in a reference position,and two other pointings revealed two and four independent signalsrespectively). Except for 2 strong \normalsize H \footnotesize Iemitters identified in the shallow Zone of Avoidance \normalsize H\footnotesize I survey (Henning et al. \cite{Henning}), all \normalsizeH \footnotesize I detections are new. An analysis of the properties ofthe observed and detected galaxies prove that pointed \normalsize H\footnotesize I observations of highly obscured galaxies allow thetracing of a population of nearby, intrinsically large and bright spiralgalaxies that otherwise would not be recovered. The new data identifieda previously unrecognized nearby group at l ~ 287. o5, b ~-9. o5, V ~ 1700 km s-1, the continuation of theHydra/Antlia filament on the opposite side of the Galactic plane, andhelped to delimit a distinct void in the ZOA centered at 2000 kms-1. Tables 1 and 2 are also available in electronic form atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/391/887
| Radio continuum morphology of southern Seyfert galaxies
We present radio observations for 29 southern Seyfert galaxies selectedfrom a volume limited sample with cz<3600 km s(-1) , and declinationdelta <0{(deg} ) r. Objects with declination -30{(deg} }r
| Catalogue of HI maps of galaxies. I.
A catalogue is presented of galaxies having large-scale observations inthe HI line. This catalogue collects from the literature the informationthat characterizes the observations in the 21-cm line and the way thatthese data were presented by means of maps, graphics and tables, forshowing the distribution and kinematics of the gas. It containsfurthermore a measure of the HI extension that is detected at the levelof the maximum sensitivity reached in the observations. This catalogueis intended as a guide for references on the HI maps published in theliterature from 1953 to 1995 and is the basis for the analysis of thedata presented in Paper II. The catalogue is only available inelectronic form at the CDS via anonymous ftp 130.79.128.5 orhttp://cdsweb.u-strasbg.fr/Abstract.html
| 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.
| Parameters of 2447 Southern Spiral Galaxies for Use in the Tully-Fisher Relation
I-band luminosities, rotational velocities, and redshifts of 1092 spiralgalaxies have been measured by CCD photometry and Hα spectroscopyusing the 1 m and 2.3 m telescopes at Siding Spring Observatory,respectively. The results are tabulated. Luminosity profiles andHα rotation curves are given for the galaxies. When these resultsare combined with similar data for 1355 spiral galaxies publishedpreviously (Mathewson, Ford, & Buchhorn, hereafter Paper I), itprovides a large, uniform, and unique data set with which to measure,via the Tully-Fisher relation, the peculiar velocities of galaxies inthe local universe to a distance of 11,000 km s^-1^ (Mathewson &Ford). Taking advantage of the opportunity for publishing this data inmachine-readable form, in the CD-ROM, we have also included similar datafor the 1355 galaxies in Paper I.
| 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.
| 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.
| The local metallicity-surface brightness relationship in galactic disks
We present the results of a first attempt to employ multiaperture masksto obtain spectrophotometry of H II regions in nearby galaxies. A totalof 97 H II regions in six southern spiral galaxies were observed using acombination of multiaperture masks and conventional long-slitspectrophotometry. The oxygen abundances derived from the multiaperturemask observations using the empirical abundance diagnosticR23 are shown to be consistent with those from long-slitspectra and generally show better reproducibility and object definition.Although the number of objects that can be observed simultaneously withthis particular system is still quite limited compared with eitherimaging spectrophotometry or fiber-fed spectrographs, the spectralresolution offered and high throughput in the blue help makemultiaperture spectrophotometry a competitive technique for increasingthe sampling of H II regions in both radial distance and luminosity.There is still no clear trend of abundance gradient with either thegalaxy's luminosity or its Hubble type, although the extrapolatedcentral abundance does appear to correlate with galaxy luminosity/mass.In order to avoid difficulty in choosing an appropriate normalizingradius, we instead plot the oxygen abundance against the underlyingI-band surface brightness at the radial distance of the H II region andconfirm the existence of a local metallicity-surface brightnessrelationship within the disks of spiral galaxies. Although the simpleclosed-boc model of galaxy evolution predicts almost the right form ofthis relationship, a more realistic multizone model employingexpnentially decreasing gas infall provides a more satisfactory fit tothe observational data, provided the expected enriched gas return fromdying low-mass stars shedding their envelopes at late epochs is properlytaken into account. This same model, with a star formation law basedupon self-regulating star formation in a three-dimensional disk (Dopita& Ryder 1994), is equally capable of accounting for the observedrelationship between recent massive star formation and stellar surfacebrightness (Ryder & Dopita 1994).
| A Preliminary Classification Scheme for the Central Regions of Late-Type Galaxies
The large-scale prints in The Carnegie Atlas of Galaxies have been usedto formulate a classification scheme for the central regions oflate-type galaxies. Systems that exhibit small bright central bulges ordisks (type CB) are found to be of earlier Hubble type and of higherluminosity than galaxies that do not contain nuclei (type NN). Galaxiescontaining nuclear bars, or exhibiting central regions that are resolvedinto individual stars and knots, and galaxies with semistellar nuclei,are seen to have characteristics that are intermediate between those oftypes CB and NN. The presence or absence of a nucleus appears to be auseful criterion for distinguishing between spiral galaxies andmagellanic irregulars.
| Quantitative Morphology of Bars in Spiral Galaxies
As suggested by numerical simulations, the axis ratio of the bar is afundamental parameter to describe the dynamical evolution of a barredgalaxy. In a first-order approximation considering bars as ellipticalfeatures, visual measurements of bar axis ratios and lengths of 136spiral galaxies were performed on photographs of good linear scale.Despite the limitations affecting such measurements, morphologicalproperties of bars in spirals along the Hubble sequence as well as therelationship between the bar axis ratio and nuclear star formationactivity are studied. It is found that the relative length of bars inearly-type galaxies is, on average, about a factor of 3 larger than thelength observed in late-type spirals. Also, a relation between barlengths and bulge diameters is observed for both early-type andlate-type spirals, confirming results from previous works. Furthermore,although the number of objects is small, there is an apparentcorrelation between the presence of nuclear star formation activity andthe bar axis ratio: about 71% of the starburst galaxies included in thesample have a strong bar (b/a < 0.6). The introduction of thesequantitative parameters in galaxy classification schemes is discussed.
| 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.
| The Variation of the Scalelengths of Galaxies at Different Wavelengths
We develop model profiles of spiral galaxies with different amounts andgeometries of disc absorption and different bulge sizes. These are usedto investigate whether there are any systematic changes in the profilesof absorbed galaxies at different wavelengths, and whether measurementof the scalelength of disc galaxies at different wavelengths can be usedas a test of whether galaxies are optically thick or thin, Using modelswith realistic geometries where the dust vertical scaleheight is lessthan the stars vertical scaleheight, and including a bulge component, wefind very little difference in the B-band and I- or H-band scalelengths,even for optical depths as high as τ_B_ = 20. When we compare thepredictions of our models to our own data and the data in theliterature, we find that the observational uncertainties are greaterthan the predicted effects, rendering this test of optical depthessentially useless. However, our models do predict subtle trends anddifferences in the surface brightness profiles of galaxies when viewedat different wavelengths. With the increasing availability ofnear-infrared arrays, it should be possible to test whether thesepredicted differences are, in fact, seen.
| Galaxy properties in different environments. 1: The sample
This paper presents two galaxy samples, respectively in a high and in alow local density environments, that were generated from the SouthernSky Redshift Survey (SSRS) catalog using objective criteria. Apreliminary comparison of physical properties in these two samplesreveals that galaxies in high-density environments tend to be under ahigher starbursting activity, have a deficiency of the neutral hydrogencontent, present a higher fractional Seyfert population and a higherfraction of barred spirals as well. The present samples are intended tobe used in future spectroscopic observations for more detailedinvestigation.
| On the law of star formation in disk galaxies
The observational relationship between the stellar surface brightnessand the surface brightness in H-alpha in galactic disks is shown to bedetermined by the law of star formation in disk galaxies. Assuming therate of star formation to take a generalized Schmidt power-law formdependent on both the total local matter surface density,sigmag; d sigma*/dt = epsilonsigmaTn, we find that the observations constrain(n + m is greater than 1), and that the best fit is obtained for 1.5 isless than (n + m) is less than 2.5. Both a Schmidt Law of the form dsigma*/dt = epsilon sigmag, and a star-formationlaw of the form d sigma*/dt = epsilon Omegasigmag, where Omega is the angular velocity at the radialpoint considered, seem to be excluded by observations. The observedscatter in the stellar surface brightness versus H-alpha surfacebrigtness versus H-alpha surface relationship can be interpreted as ascatter in the ratio of galaxian age to star-formation efficiency;younger galaxies being more gas-rich, and currently more active informing stars. Finally, we discuss particular forms of the Schmidt Lawgiven by theory. We show that a model having n = 1/3 and m = 5/3, whichgives a particularly good fit to the observations, follows as aconsequence of stochastic self-regulating star formation moderated bycloud-cloud interactions in the disk potential, and by the energeticprocesses associated with the formation of massive stars. This modelsexplicitly includes the secular evolution of the vertical structure ofthe gaseous and stellar components of galactic disks, and the effectofthe galaxian potential.
| The relationship between past and present star formation in galactic disks from CCD surface photometry
We present some results of a major new multiband imaging survey of 34nearby southern spiral galaxies. Images in V, I, H-alpha, and theadjacent red continuum have been obtained using a CCD and focal reduceron the 1.0 and 2.3 m telescopes at Siding Spring Observatory. Surfacephotometry using the GASP software package is used first to derive thedisk orientation parameters, then to provide deprojected radial surfacebrightness profiles for each galaxy in V and I, as well as thecontinuum-subtracted H-alpha, which traces the present-day rate ofmassive star formation. In the outer disk, the H-alpha profile can bereasonably well fitted by an exponential disk, but with a scale lengthmuch longer than the V scale length, which itself tends to be sligtlylonger than the I scale length. An almost universal relationship isobserved in the disk between the H-alpha surface brightness and theI-band surface brightness at a given radius, with any residual offsetfrom the mean trend being a weak function of the morphological type.Thus the rate of massive star formation per unit area in the disk isclosely related to the old stellar mass surface density at each radius,and to the mean H I surface density in the disk as a whole. This formsthe basis for a law of (or rather, a consistent on) massive starformation in the disks of spiral galaxies, one that has a surprisingdegree of independence from both galactic dynamics and molecular gascontent.
| An H-alpha atlas of nearby southern spiral galaxies
We present an atlas of CCD images of 25 nearby southern spiral galaxiestaken through narrow-band (15 A) H-alpha filters, and accompanying redcontinuum (6676 A) images. Most of these galaxies have never previouslybeen imaged in H-alpha and will complement the earlier photographicatlas of Hodge and Kennicutt. We comment on the individual distributionsof the H II regions in relation to the morphology and characteristics ofeach galaxy. Nearly half of the galaxies surveyed exhibit ratherasymmetrical distributions of star formation activity, even though thestellar distributions may be quite regular. Among galaxies possessingboth a strong stellar bar and an encircling inner ring, there appears tobe a decrease in the number of H II regions tracing out the bar as thenumber of H II regions in the ring itself increases, and vice versa. Theimages should prove useful mainly as finding charts for in-depth studiesof the H II region populations, as well as for the purposes ofdetermining abundance gradients and the kinematics of these galaxies.
| The nature of unidentified far-infrared point sources
Sources discovered by the Infrared Astronomical Satellite with spectrathat rise steeply from 60 to 100 microns are a mixed sample of externalgalaxies, condensations in the interstellar medium, and potentiallyunknown astronomical objects. Sources in regions of low total H I columndensity (as determined with the all-sky 21-cm line surveys), and with nonearby cataloged external galaxy, were observed for presence of 20-cmcontinuum emission (with the NRAO VLA), enhanced 21-cm H I line emission(with the NAIC Arecibo 305 m), and molecular line emission (with theNRAO 12 m, HCRO 6 m, and FCRAO 14 m). Based on the CO detection rate, 70percent of our sample are small interstellar molecular clouds. Theremainder are mostly faint external galaxies. The dust column densitiesof the interstellar condensations were determined from the IR flux,using a spherical-cloud model for the radiative transfer of theinterstellar radiation field (ISRF). The CO column densities weredetermined using the large-velocity-gradient model for the excitationand radiative transfer of the rotational transitions. About half of theinterstellar sources have normal dust-to-gas ratios and ISRF heating.Sources with excess infrared emission, compared to the molecular columndensity, are protostellar candidates.
| IRAS CPC Observations of Galaxies - Part One - Catalog and Atlas
. - We present the results of far-infrared imaging observations of 258regions of 12' x9' each centered on a selected individual galaxy, aclose pair, or a compact group of galaxies mapped at 50 and 100 micronwavelength with the CPC instrument of the IRAS satellite. The CPCinstrument has a significantly better resolution than the IRAS Surveyinstrument at these wavelengths, i.e. a round beam with a FWHM of about80" at 50 microns and 95" at 100 microns, respectively, intended to bematched to the diffraction limit of the telescope at 100 microns. Themaps were made using a new algorithm to correct for gain variations,which gives better results than the one used previously for the imagesmade available on tape in 1985. Of 262 objects observed, 167 and 188were detected at 50 and 100 microns, respectively, about 85% of thegalaxies from the same sample listed as detected by the Surveyinstrument in the IRAS Point Source Catalog. For all 55 galaxiesresolved (i.e. with a FWHM major axis diameter exceeding 1.6 times thebeam FWHM and/or extended lower-level emission) by the CPC we alsopresent the averaged maps at 50 and 100 microns. These 55 objectsinclude 35 for which there are no published maps obtained with the IRASSurvey instrument. We rescaled the flux densities of the published CPCmaps using the more accurate IRAS Survey instrument data, since theabsolute flux density calibration of the CPC is only accurate to about+/-60%. We also present images of a triplet of galaxies associated witha single Survey point source, which were resolved into separate sourcesby the CPC.
| Optical studies of star formation in normal spiral galaxies - Radial characteristics
First results of a new, homogeneous CCD imaging survey of nearbysouthern spiral galaxies in V, I, and H-alpha are presented. Ellipticalaperture photometry has been used to determine the deprojected surfacebrightnesses as a function of galactocentric radius, and thus to tracethe past and present star formation behavior. From a sub-sample of ninemainly barred spirals, we find a couple of notable trends. Firstly,nearly all of the barred spirals show evidence of significant levels ofongoing star formation in the bulge, probably fed by gas inflow alongthe bar. Secondly, the disk H-alpha profiles are quite shallow comparedwith the broadband exponential disks, implying a relative insensitivityof the current star formation rate to the surface density of starsalready formed. In both the bulge and the disk, the gas consumptiontimescales are such as to require gas replenishment, e.g., by radialinflow.
| Mean galaxy luminosity classifications
To prepare a catalog of weighted means on the classification system ofvan den Bergh, we have combined eight independent lists of luminosityclass estimates, L. Luminosity class values from each set weretransformed to the standard system and weighted according to the errorsderived through a statistical comparison of L differences betweencatalog pairs. Relations were derived for predicting accidental errorsassociated with galaxy diameter and inclination. In addition, we presentformulas for correcting systematic errors associated with diameter andinclination. Finally, we tabulate a high weight subsample of the meanluminosity classes usable as standards. Most values are tabulated in theThird Reference Catalog of Bright Galaxies.
| A southern sky survey of the peculiar velocities of 1355 spiral galaxies
The paper presents data from photometric and spectroscopic observationsof 1355 southern spiral galaxies and uses them to determine theirdistances and peculiar velocities via the Tully-Fisher (TF) relation.I-band CCD surface photometry was carried out using the 1-m and 3.9-mtelescopes at Siding Spring Observatory. H-alpha rotation curves for 965galaxies and 551 H I profiles are presented. The physical parameters,photometric and velocity data, distances, and peculiar velocities of thegalaxies are presented in tabular form. The mean distance, systemicvelocity, and average peculiar velocity of 24 clusters in the sample aregiven. TF diagrams are presented for each cluster.
| 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.
| An optical catalog of extragalactic emission-line objects similar to quasi-stellar objects
A catalog of 935 galaxies which have optical properties similar to thoseof QSOs is given. A subsidiary table of cross-identifications enablesthe reader to relate the name of a given object to its coordinate name.Most of the objects appear to be nonstellar. The majority, more than700, have redshifts z = 0.2 or less, and have mostly been classified asSeyfert galaxies, N systems, or radio galaxies. The Hubble diagram forall of the objects with z = 0.2 or less is shown. The redshiftdistribution peaks at z = 0.025, but there are about 200 powerful radiogalaxies in the extended tail of the distribution which have z greaterthan 0.2. There is a separate and distinct peak in the redshiftdistribution at z = 0.06.
| A new subclass of Type II supernovae?
Observations of Type II supernovae are reported, focusing on evidencesupporting the need for a new SN subclass. The objects that are likelyto consistute the new subclass are listed and the properties thatseparate these objects from the mass of SN II objects are described.
| Revised supernova rates in Shapley-Ames galaxies
Observations of 855 Shapley Ames galaxies made from November 1, 1980 toOctober 31, 1988, together with improved supernova luminosities, havebeen used to derive the frequency of supernovae of different types, andthe results are presented in tables. From a uniform database of 24supernovae discovered, the following SN rates are found, expressed in SNper century per 10 to the 10th L(B)(solar): SN Ia, 0.3; SN Ib, 0.3; andSN II, 1.0. The present data confirm the relatively high frequency of SNII in late-type galaxies that has been found by many previousinvestigators.
| Radio emission from supernovae. I - One to twelve year old supernovae
All recorded optical supernovae brighter than 14.0 mag from SN 1970A toSN 1981A were observed in May 1982 using VLA at 6 cm. Apart from theknown radio supernovae (SN 1970G, SN 1979C, and SN 1980K), radioemissions were not detected from any of the objects to a limit of about0.5 mJy. Limits on mass-loss rates from the presupernova systems areestablished. It is found that Type Ia Sns originate in systems whichcontain very little circumstellar material at the time of explosion.These systems are very different from those which originate Type Ib Sns.With some exceptions, Type II SNs originate with the high presupernovamass-loss rates expected from red supergiant progenitors with originalmain-sequence masses greater than about 8 solar masses.
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