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Seyfert Galaxies with Circumnuclear/Nuclear Starbursts
In this paper, we present our preliminary results on Seyfert galaxieswith circumnuclear/nuclear starburst (SB) activity. We have searched therecent available literature and found 76 active galaxies with clearevidence of nuclear SB activity, among which 16 are Seyfert 1s, 51Seyfert 2s, and 9 LINERs. After studying the 51 Seyfert 2s, we find thatthose Seyfert 2s with hidden Seyfert 1 nuclei, have similarInfrared-Radio properties as Seyfert 1 galaxies, and are different from``real'' Seyfert 2s without a hidden Seyfert 1 nucleus. The later aresimilar to starburst galaxies.
| The Active Merging System ESO 202-G23 (Carafe Nebula)
We present the results of observations both in imaging and spectroscopyof the nearby active galaxy ESO 202-G23 (Carafe Nebula). The main resultof this investigation is that the peculiar morphology of the galaxy,formerly attributed to the presence of an asymmetric bar, is produced bythe merging of two galaxies both hosting an active nucleus. Our deep Rimage reveals unexpectedly the presence of a knot (G2), not visible inthe B image, at 3.5 kpc on the northern of the nucleus (G1), classifiedin the literature as a Seyfert 2. A long-slit spectrum provides evidencethat G1 is a Seyfert 1.5 nucleus and that G2 is also a nucleus, showingfeatures typical of a LINER heavily reddened by dust. The presence oftails and plumes in the outermost parts of the galaxy and the double Ushape of the rotation curve of the gas around G1 and G2 strongly supportthe hypothesis of a merger that occurred 106-109years ago, as suggested by the comparison of the current (14Msolar yr-1) and the recent (24 Msolaryr-1) star formation rates. The system ESO 202-G23 is aninfrared bright source(LFIR/Lsolar=2.18×1010) and theIRAS flux ratios suggest a predominantly thermal origin of the infraredemission. The analysis of the IRAS data allows us to obtain someimportant properties concerning both the gas and the dust:Td(warm)~36 K; Md(warm)=4.1×106Msolar Td(cold)~21 K;Md(cold)=(6.9-8.3)×107 MsolarMHI=8.6×109 MsolarMHII=(2.3-4.3)×109 MsolarMgas=(1.1-1.3)×1010 Msolar. Thederived mass-to-light ratio MHI/LB=2.23 and thevalue of the parameter K=vmax/rmax, K(G1)=201,K(G2)=179, indicate that the precursor is not later than Sbc. Based onobservations collected at ESO, La Silla, Chile.
| The merger stage of the ultra-luminous infrared galaxy IRAS 03158+4227
We examine the merger stage of IRAS 03158+4227, one of the most luminousULIRGs from the IRAS 2 Jy sample. Deep optical images are presentedalong with high-resolution NIR images and optical low-resolutionspectra. IRAS 03158+4227 is confirmed as a component of anequal-luminosity binary galaxy with a nuclei separation of 47h75-1 kpc. A long lopsided tail emanating from thecompanion, which harbours an active nucleus, is the most prominentpeculiar feature of the binary. The results of numerical simulationspermit the interpretation of this structure as a product of the tidalinteraction between the two components. If the infrared-activity of IRAS03158+4227 is also dynamically triggered by this process, this wouldimply that the ULIRG phenomenon is not restricted to the final stage ofa binary merger. Alternatively, the system may be a multiple mergerwhere the partner(s) has/have already coalesced.
| Southern Isolated Galaxy Triplets
Seventy-six isolated triple systems of galaxies with declinatiosnδ<-3° were selected using ESO/SERC and POSS-I sky surveydata. The equatorial coordinates, configuration types, angular sizes,component angular separations, component morphological types, totalmagnitudes, and other parameters are reported for each triplet.Radial-velocity estimates are available for all components in 33 of the76 triplets. The median values of the main dynamicalparametersradial-velocity dispersion, mean harmonic radius,absolute magnitudes of member galaxies, and mass-to-luminosityratiosare similar to those obtained earlier for 83 isolatedtriple systems with δ>-3°.
| 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.
| The QDOT all-sky IRAS galaxy redshift survey
We describe the construction of the QDOT survey, which is publiclyavailable from an anonymous FTP account. The catalogue consists ofinfrared properties and redshifts of an all-sky sample of 2387 IRASgalaxies brighter than the IRAS PSC 60-μm completeness limit(S_60>0.6Jy), sparsely sampled at a rate of one-in-six. At |b|>10deg, after removing a small number of Galactic sources, the redshiftcompleteness is better than 98per cent (2086/2127). New redshifts for1401 IRAS sources were obtained to complete the catalogue; themeasurement and reduction of these are described, and the new redshiftstabulated here. We also tabulate all sources at |b|>10 deg with noredshift so far, and sources with conflicting alternative redshiftseither from our own work, or from published velocities. A list of 95ultraluminous galaxies (i.e. with L_60μm>10^12 L_solar) is alsoprovided. Of these, ~20per cent are AGN of some kind; the broad-lineobjects typically show strong Feii emission. Since the publication ofthe first QDOT papers, there have been several hundred velocity changes:some velocities are new, some QDOT velocities have been replaced by moreaccurate values, and some errors have been corrected. We also present anew analysis of the accuracy and linearity of IRAS 60-μm fluxes. Wefind that the flux uncertainties are well described by a combination of0.05-Jy fixed size uncertainty and 8per cent fractional uncertainty.This is not enough to cause the large Malmquist-type errors in the rateof evolution postulated by Fisher et al. We do, however, find marginalevidence for non-linearity in the PSC 60-μm flux scale, in the sensethat faint sources may have fluxes overestimated by about 5per centcompared with bright sources. We update some of the previous scientificanalyses to assess the changes. The main new results are as follows. (1)The luminosity function is very well determined overall but is uncertainby a factor of several at the very highest luminosities(L_60μm>5x10^12L_solar), as this is where the remainingunidentified objects are almost certainly concentrated. (2) Thebest-fitting rate of evolution is somewhat lower than our previousestimate; expressed as pure density evolution with density varying as(1+z)^p, we find p=5.6+/-2.3. Making a rough correction for the possible(but very uncertain) non-linearity of fluxes, we find p=4.5+/-2.3. (3)The dipole amplitude decreases a little, and the implied value of thedensity parameter, assuming that IRAS galaxies trace the mass, isΩ=0.9(+0.45, -0.25). (4) Finally, the estimate of density varianceon large scales changes negligibly, still indicating a significantdiscrepancy from the predictions of simple cold dark matter cosmogonies.
| The Stellar Content of Active Galaxies
We present the results of a long-slit spectroscopic study of 38 activeand four normal galaxies. Stellar absorption features, continuum coloursand their radial variations are analysed in an effort to characterizethe stellar population in these galaxies and detect the presence of afeatureless continuum underlying the starlight spectral component.Spatial variations of the equivalent widths of conspicuous absorptionlines and continuum colours are detected in most galaxies. Star-formingrings, in particular, leave clear fingerprints in the equivalent widthsand colour profiles. We find that the stellar populations in the innerregions of active galaxies present a variety of characteristics, andcannot be represented by a single starlight template. Dilution of thestellar lines by an underlying featureless continuum is detected in mostbroad-lined objects, but little or no dilution is found for most of the20 type 2 Seyferts in the sample. Colour gradients are also ubiquitous.In particular, all but one of the observed Seyfert 2s are redder at thenucleus than in its immediate vicinity. Possible consequences of thesefindings are briefly outlined.
| Chemical Abundance Calibrations for the Narrow-Line Region of Active Galaxies
We investigate two chemical abundance calibrations for the narrow-lineregion (NLR) of active galaxies in terms of three easily observableoptical emission-line ratios, namely, [O iii] lambdalambda4959,5007/Hβ [N ii] lambdalambda6548, 6584/Hα and [O ii]lambda3727/[O iii] lambdalambda4959, 5007. The calibrations are obtainedfrom a grid of models on the assumption that the main processresponsible for the production of these lines is photoionization by a``typical'' active galactic nucleus continuum. The elemental abundancesvary with oxygen, except nitrogen, which is assumed to be a product ofsecondary nucleosynthesis. The calibrations are calculated for the range8.4 <= 12 + log (O/H) <= 9.4 and tested using NLR data for asample of Seyfert galaxies and LINERs that have H ii regions in thevicinity of the nucleus. The gaseous abundances of these H ii regionshave been determined in previous works, and the NLR abundances areobtained on the assumption that they can be extrapolated from those ofthe H ii regions. The calibrations work very well for the Seyfertgalaxies, yielding abundance values that agree with those obtained fromthe H ii regions, and can thus be used for quick estimates of thechemical abundances of the NLRs. For the LINERs, the calibrations yieldlower values than those derived from the corresponding H ii regions,suggesting that the assumptions of the models do not apply for them andthat there are different physical processes at work in the NLR of theLINERs.
| 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.
| A catalogue of spatially resolved kinematics of galaxies: Bibliography
We present a catalogue of galaxies for which spatially resolved data ontheir internal kinematics have been published; there is no a priorirestriction regarding their morphological type. The catalogue lists thereferences to the articles where the data are published, as well as acoded description of these data: observed emission or absorption lines,velocity or velocity dispersion, radial profile or 2D field, positionangle. Tables 1, 2, and 3 are proposed in electronic form only, and areavailable from the CDS, via anonymous ftp to cdsarc.u-strasbg.fr (to130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
| A Survey for H 2O Megamasers in Active Galactic Nuclei. II. A Comparison of Detected and Undetected Galaxies
A survey for H2O megamaser emission from 354 active galaxies hasresulted in the detection of 10 new sources, making 16 known altogether.The galaxies surveyed include a distance-limited sample (coveringSeyferts and LINERs with recession velocities less than 7000 km s-1) anda magnitude-limited sample (covering Seyferts and LINERs with mB <=14.5). In order to determine whether the H2O-detected galaxies are"typical" active galactic nuclei (AGNs) or have special properties thatfacilitate the production of powerful masers, we have accumulated adatabase of physical, morphological, and spectroscopic properties of theobserved galaxies. The most significant finding is that H2O megamasersare detected only in Seyfert 2 and LINER galaxies, not Seyfert 1's. Thislack of detection in Seyfert 1's indicates either that they do not havemolecular gas in their nuclei with physical conditions appropriate toproduce 1.3 cm H2O masers or that the masers are beamed away from Earth,presumably in the plane of the putative molecular torus that hides theSeyfert 1 nucleus in Seyfert 2's. LINERs are detected at a similar rateto Seyfert 2's, which constitutes a strong argument that at least somenuclear LINERs are AGNs rather than starbursts, since starbursts havenot been detected as H2O megamasers. We preferentially detect H2Oemission from the nearer galaxies and from those that are apparentlybrighter at mid- and far-infrared and centimeter radio wavelengths.There is also a possible trend for the H2O-detected galaxies to be moreintrinsically luminous in nuclear 6 cm radio emission than theundetected ones, though these data are incomplete. We find evidence thatSeyfert 2's with very high (NH > 1024 cm-2) X-ray--absorbing columnsof gas are more often detected as H2O maser emitters than Seyfert 2'swith lower columns. It may be that the probability of detecting H2Omaser emission in Seyfert galaxies increases with increasing column ofcool gas to the nucleus, from Seyfert 1's through narrow-line X-raygalaxies to Seyfert 2's.
| Optical Rotation Curves and Linewidths for Tully-Fisher Applications
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114.2402C&db_key=AST
| 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.
| A Survey for H 2O Megamasers in Active Galactic Nuclei. I. Observations
We report an extensive search for 22 GHz H_2_O maser emission fromnearby active galaxies. Our sample includes all Seyfert and LINERgalaxies listed in the Huchra catalog or the Veron-Cetty & Veroncatalog with recessional velocities less than 7000 km s^-1^, and allSeyfert galaxies and LINERs in Huchra's catalog with m_b_ <= 14. Inaddition to these distance- and magnitude-limited samples, we have alsoobserved a number of active galaxies, including radio galaxies, athigher redshift; In all, some 354 galaxies have been surveyed. Ten newH_2_O megamaser sources have been detected, resulting in 16 galaxiesthat are currently known to contain H_2_O masers with isotropicluminosities greater than 20 L_sun_. Of the observed active galaxieswith cz < 7000 km s^-1^, 5.4% have detectable H_2_O megamaseremission. This fraction increases to 11% for those sources with cz <2000 km s^-1^. The newly discovered megamaser sources were monitored onsubsequent observing runs. The strength of the maser features varies forthese sources, as they do for Galactic masers. Three of the galaxieshave sufficient data to test for velocity changes of narrow masercomponents comparable in magnitude to those of the well-studied systemicfeatures in NGC 4258. The maser line in one of these galaxies-NGC2639-is found to have a systematic redward velocity drift of 6.6 +/- 0.4km s^-1^ yr^-1^. No systematic velocity drifts are found for the othertwo sources. We also report large apparent velocity changes in theunusual broad H_2_O emission feature in NGC 1052.
| Circumnuclear Star Formation in Active Galaxies
We study the gas kinematics and chemical abundances in the inner regionsof six galaxies with active galactic nuclei. The galaxies were selectedfor having star-forming regions in rings or spirals within a fewkiloparsecs of the nucleus. The goal of the project is to search for anyconnections between the gas-dynamics, the chemical abundances, and thenuclear activity. Narrowband images have been obtained to map out theionized gas. Medium-dispersion long-slit spectroscopy at severalpositions over the nuclear region has been used to obtain the gaseousvelocity field and distribution of excitation. The H II regions in therings are located near the turnover point of the rotation curves,suggesting association with the inner Lindblad resonance. The nuclearring in the LINER NGC 1326 may be located between the two inner Lindbladresonances, and the inner rings in the Seyfert 2 galaxy NGC 3081 and theLINER/Seyfert 1 NGC 7213 may be associated with the {OMEGA} - κ/4resonance. A warm ionized medium (WIM) is found to pervade the innerregion in all galaxies. There is a correlation between the [NII]/Hα and [S II/Hα ratios and the FWHM of the [N II]λ 6584 emission line in this WIM, indicating that shockscontribute to the ionization of the gas. We show that contamination bythis diffuse emission increases the measured [N II]/Hα and [SII]]Hα ratios at H II regions close to the nuclei and thus mayaccount, in part, for the systematically higher [N II]/Hα and [SII]/Hα found in the present work and by previous authors for near-nuclear H II regions compared with H II regions farther out in the diskof the galaxy. In the present paper, we correct for this contaminationby interpolating the contribution of the WIM at the H II regions andsubtracting it off. Oxygen and nitrogen abundances are obtained for 18 HII regions and are extrapolated to obtain the abundance of the nucleargas, which is found to range from solar to 2 times solar for oxygen andfrom 2 to 4 times solar for nitrogen. Such values are similar to thoseobserved in nonactive galaxies with the same luminosity andmorphological type and do not support the idea that the central regionsof active galaxies have undergone unusual chemical processing.
| Rotation Curves of 967 Spiral Galaxies
We present the rotation curves of 967 southern spiral galaxies, obtainedby deprojecting and folding the raw Hα data originally publishedby Mathewson, Ford, & Buchhorn (1992). For 900 objects, we alsopresent, in figures and tables, the rotation curves smoothed on scalescorresponding to 5%-20% of the optical size; of these, 80 meet objectiveexcellence criteria and are suitable for individual detailed massmodeling, while 820, individually less compelling mainly because of themoderate statistics and/or limited extension, are suitable forstatistical studies. The remaining 67 curves suffer from severeasymmetries, small statistics, and large internal scatter that maylargely limit their use in galaxy structure studies. The deprojectedfolded curves, the smoothed curves, and various related quantities areavailable via anonymous ftp at galileo.sissa.it in the directory/users/ftp/pub/psrot.
| 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.
| Integrated photoelectric magnitudes and color indices of bright galaxies in the Johnson UBV system
The photoelectric total magnitudes and color indices published in theThird Reference Catalogue of Bright Galaxies (RC3) are based on ananalysis of approximately equals 26,000 B, 25,000 B-V, and 17,000 U-Bmultiaperture measurements available up to mid 1987 from nearly 350sources. This paper provides the full details of the analysis andestimates of internal and external errors in the parameters. Thederivation of the parameters is based on techniques described by theVaucouleurs & Corwin (1977) whereby photoelectric multiaperture dataare fitted by mean Hubble-type-dependent curves which describe theintegral of the B-band flux and the typical B-V and U-B integrated colorgradients. A sophisticated analysis of the residuals of thesemeasurements from the curves was made to allow for the random andsystematic errors that effect such data. The result is a homogeneous setof total magnitudes BTA total colors(B-V)T and (U-B)T, and effective colors(B-V)e and (U-B)e for more than 3000 brightgalaxies in RC3.
| The Montreal Blue Galaxy survey. 2: Second list of UV-bright candidates
We present and discuss the second list of the Montreal Blue Galaxysurvey. Following the inspection of 71 plates, we found 237 newcandidates with B less than 15.5. 73 percent of them are also detectedby Infrared Astronomy Satellite (IRAS). Spectrophotometry was carriedout, at medium resolution, for a subset of 40 objects leading to theidentification of three new AGNs and producing 13 new radial velocities.Spectral classification of our candidates confirms our previous findingthat the majority of our candidates are starburst nucleus galaxiessimilar to the objects studied by Balzano in 1983. Our survey is biasedagainst the high excitation starburst H II galaxies and the LINERgalaxies. Metallicities of our galaxies are found to be from log(O/H)=8.4 to 9.0, which suggests galaxies in advanced stages of chemicalevolution.
| 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.
| A catalog of southern groups of galaxies
A catalog of groups of galaxies identified in the southern Galactic capis presented. This catalog was constructed utilizing the group-findingalgorithm developed by Huchra and Geller (1982) to analyze galaxysamples with well-defined selection criteria and complete velocityinformation.
| A comparison of the physical conditions in nuclear, hotspot, and disk H II regions
The physical properties of H II regions situated in galactic nuclei, inregions immediately surrounding the nuclei ('hotspots'), and in thedisks are compared, using optical spectrophotometry and radio-continuumdata. The integrated properties (size, H-alpha luminosity) of the nucleiand hotspots are similar to those of the brightest disk H II regions,but important differences are found in the emission-line spectra,internal structure, and radio properties. Roughly half of the H IIregion and starburst nuclei show evidence for a secondary ionizationcomponent, either an active nucleus or large-scale shocks. This featureis seen both in the line ratios and line profiles. This supports theidea that many spiral nuclei are composite in nature, with a centralLINER or Seyfert-like nucleus surrounded by star-forming regions.
| BV photometry and radial velocities of southern spiral galaxies
Multiaperture photoelectric photometry for 119 southern spiral galaxiesand heliocentric velocities for 98 southern spiral galaxies obtainedfrom image-tube spectrograms are presented. The data were collected in1976, 1977, and 1978 at Cerro Tololo Inter-American Observatory. Themagnitude and (B-V) color index are compared with aperture diameter inorder to determine if the present data correlate with previousmeasurements. The comparison reveals that the data correspond. Theinternal measurement error of the radial velocities is estimated; it isobserved that the internal error for one measurement is 41 km/sec.
| Warmers - The missing link between Starburst and Seyfert galaxies
Recent observational and theoretical work has shown that, as aconsequence of mass loss in the form of stellar winds in the last stagesof their evolution, massive stars can reach effective temperatures ofmore than 100,000 K, being observed as extreme WC or WO Wolf-Rayetstars. In this paper, the effect of these hot stars (which are calledWarmers) on the evolution of metal-rich giant H II regions is examined.It is shown that as a function of age, the emission-line spectrum of theHe II region evolves first into a type 2 Seyfert spectrum and then intoa Liner-type spectrum. It is suggested that many of the active nucleiclassified as type 2 Seyferts and Liners are not associated with anonthermal power source but rather with violent star formation activityat high metal abundance.
| Southern Galaxy Catalogue.
Not Available
| Recognition and classification of galaxies with optical jets
Deep images and spectra are presented for galaxies reported in variouscatalogs to have jets, as well as in a search of the SRC J survey platesin a region near the south galactic pole. Most of these are shown to besuperpositions, polar rings, tidal features, or artifacts of theoriginal plate material. Examples are shown of ten ways that false jetscan be produced, with more detailed case studies for several systems.Based on this experience, several criteria for the brightness, location,and symmetry of genuine optical jets are suggested, which should yieldsurvey samples much less contaminated by 'false alarms' than existingones. Among the objects that remain as optical-jet candidates, ESO0610-23 shows a linear, radial chain of H II regions on the outskirts ofan amorphous system with complex internal structure, UGC 3995 is a closepair of spirals, one of which has a type 2 Seyfert nucleus and apparentknotty jet, and NGC 1598 has the radial features previously reported,but considerable chaotic outer structure as well. Several systems (suchas AM 0207-49 and ESO 2330-38) illustrate the intrinsic difficulty ofseparating jets and tidal tails on morphological grounds alone incertain cases.
| Nuclear activity in two spiral galaxies with jets: NGC 1097 and 1598
The barred spiral galaxies NGC 1097 and 1598 are unusual in being knownto have optical jet-like features aligned with their nuclei; they alsohave conspicuous nuclear emission-line spectra which have been studiedin some detail in an attempt to throw light on the underlying activity.The very nuclei are either classic 'Liners' (NGC1097) or quite similarto 'Liners's (NGC 1598), and are surrounded by giant H II complexes withtypical low excitation H II region spectra. The presence of near solarabundances of N and O in these H II regions, and thus presumably also inthe nuclei themselves, supports power law photoionization models for theexcitation of 'Liners' in general, in preference to available shockmodels. Since 'Liner' spectra are now known to be common in galacticnuclei, it is not clear that these results bear any relation to thejets; but it could be of interest to search for more jets in galaxiescontaining 'Liners' at a deep and uniform level of sensitivity.
| Spectroscopic measures of galaxies, their companions, and peculiar galaxies in the southern hemisphere
Examples of apparent association of galaxies and also of single peculiargalaxies have been drawn from the Catalogue of Southern PeculiarGalaxies and Associations (Arp and Madore, in preparation).Spectroscopic measures are reported for 75 central or peculiar galaxiesand for 97 companion galaxies. Objects are identified by position andillustrated by photographic prints from the UK Schmidt (SRC) survey.Absorption and emission characteristics are tabulated for each spectrum,and heliocentric redshifts are given. The redshifts are calculated to beon the Reference Catalog II system (de Vaucouleurs et al. 1976) towithin plus or minus 50 km/s. The average redshift is repeatable towithin plus or minus 50 km/s. Differential redshifts of objects observedsimultaneously or sequentially can be considerably more accurate.
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