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The Molonglo Southern 4 Jy Sample (MS4). II. ATCA Imaging and Optical Identification
Of the 228 sources in the Molonglo Southern 4 Jy sample (MS4), the 133with angular sizes <35" have been imaged at 5 GHz at 2"-4" resolutionwith the Australia Telescope Compact Array. More than 90% of the samplehas been reliably optically identified, either on the plates of the UKSchmidt Southern Sky Survey or on R-band CCD images made with theAnglo-Australian Telescope. A subsample of 137 sources, the SMS4,defined to be a close southern equivalent of the northern 3CRR sample,was found to have global properties mostly consistent with the northernsample. Linear sizes of MS4 galaxies and quasars were found to beconsistent with galaxy-quasar unification models of orientation andevolution.
| High-frequency radio observations of the Kühr sample and the epoch-dependent luminosity function of flat-spectrum quasars
We discuss our ATCA 18.5 and 22 GHz flux density measurements ofSouthern extragalactic sources in the complete 5 GHz sample of Kühret al. (1981, A&AS, 45, 367). The high frequency (5-18.5 GHz)spectral indices of steep-spectrum sources for which we have 18.5 GHzdata (66% of the complete sample) are systematically steeper than thelow frequency (2.7-5 GHz) ones, with median α^52.7 =0.76, median α18.55 = 1.18(Sν∝ ν-α), and median steepeningΔα = 0.32, and there is evidence of an anti-correlation ofΔα18.55 with luminosity. Thecompleteness of 18.5 GHz data is much higher (89%) for flat-spectrumsources (mostly quasars), which also exhibit a spectral steepening:median α^52.7=-0.14, medianα18.55=0.16 (Sν∝ν-α), and median Δα = 0.19. Takingadvantage of the almost complete redshift information on flat-spectrumquasars, we have estimated their 5 GHz luminosity function in severalredshift bins. The results confirm that their radio luminosity densitypeaks at z_peak ≃ 2.5 but do not provide evidence for deviationsfrom pure luminosity evolution as hinted at by other data sets. Acomparison of our 22 GHz flux densities with WMAP K-band data forflat-spectrum sources suggests that WMAP flux densities may be low by amedian factor of ≃1.2. The extrapolations of 5 GHz counts andluminosity functions of flat-spectrum radio quasars using the observeddistribution of the 5-18.5 GHz spectral indices match those deriveddirectly from WMAP data, indicating that the high frequency WMAP surveydoes not detect any large population of FSRQs with anomalous spectra.
| Gamma-ray emissions of AGN and cosmological standard candles
In this work, we compile a sample which contains 71 GeV Gamma-ray-loudActive Galactic Nuclei (AGNs) (14 BL Lacs and 57 FSRQs), 53 FR I radiogalaxies and 63 FR II radio galaxies. We make a nonlinear least-squarefit to this sample, and find that the best fit value of the Hubbleconstant is H0=71.5±3.8 kms-1Mpc-1 with a reduced χ ~= 2.46 by assumingMv = -23.0 and accepting q0 = 1.0, and thecorresponding regression line has a correlation index R ~= 0.78. Thebest fit value of H0 = 71.5±3.8 kms-1Mpc-1 is in well agreement with H0 =72±8 km s-1 obtained by the Hubble Space TelescopeKey Project. Our results show that the GeV Gamma-ray emissions of AGNscan be used as cosmological standard candles indeed.
| Stellar populations in a complete sample of local radio galaxies
We investigate the nature of the continuum emission and stellarpopulations in the inner 1-3 kpc of a complete sample of 24 southernradio galaxies, and we compare the results with a control sample of 18non-active early-type galaxies. 12 of the radio galaxies are classifiedas Fanaroff-Riley type I (FR I), eight as FR II and four as intermediateor undefined type (FR x). Optical long-slit spectra are used to performspectral synthesis as a function of distance from the nucleus at anaverage sampling of 0.5-1.0 kpc and to quantify the relativecontributions of a blue featureless continuum and stellar populationcomponents of different ages. Our main finding is a systematicdifference between the stellar populations of the radio and controlsample galaxies: the former have a larger contribution from anintermediate-age (1 Gyr) component, suggesting a connection between thepresent radio activity and a starburst which occurred ~1 Gyr ago. Inaddition, we find a correlation between the contribution of the 1-Gyrcomponent and the radio power, suggesting that more massive starburstshave led to more powerful radio emission. A similar relation is foundbetween the radio power and the mean age of the stellar population, inthe sense that stronger nuclear activity is found in younger galaxies.We also find that the stellar populations of FR I galaxies are, onaverage, older and more homogeneous than those of FR IIs. Significantpopulation gradients were found in only four radio galaxies, which arealso those with more than 10 per cent of their total flux at 4020Åcontributed by age components younger than 100 Myr and/or afeatureless continuum (indistinguishable from a 3-Myr-old stellarpopulation).
| Emission lines and optical continuum in low-luminosity radio galaxies
We present spectroscopic observations of a complete subsample of 13low-luminosity radio galaxies selected from the 2-Jy sample of Tadhunteret al. The underlying continuum in these sources was carefully modelledin order to make a much-needed comparison between the emission-line andcontinuum properties of Fanaroff-Riley type Is (FRIs) and those of otherclasses of radio sources. We find that five galaxies in the sample showa measurable ultraviolet (UV) excess: two of these sources are BL Lacs,but in the remaining three galaxies we argue that the most likelycontributor to the UV excess is a young stellar component. Therefore,excluding the BL Lacs, we find that ~30 per cent of the sample showevidence for young stars, which is similar to the results obtained forhigher luminosity samples. We compare our results with far-infraredmeasurements in order to investigate the far-infrared-starburst link.The nature of the optical-radio correlations is investigated in light ofthese new available data and, in contrast to previous studies, we findthat the FRI sources follow the correlations with similar slopes tothose found for the Fanaroff-Riley type IIs. Finally, we compare theluminosities of the emission lines in the FRI and BL Lac sources andfind a significant difference between the [OIII] line luminosities ofthe two groups. Our results are discussed in the context of the unifiedschemes for low-powered radio sources.
| Emission-Line Diagnostics of the Central Engines of Weak-Line Radio Galaxies
A handful of well-studied weak-line radio galaxies (WLRGs) have beentraditionally classified as low-ionization nuclear emission-line regions(LINERs), suggesting that these two groups of active galactic nuclei(AGNs) might be related. In this paper, we present new opticalemission-line measurements for 20 WLRGs, which we supplement withmeasurements for an additional four from the literature. Classifyingthese objects by their emission-line ratios, we find that 50% of theobjects are robustly classified as LINERs, while an additional 25% arelikely to be LINERs. Photoionization calculations show that the spectralenergy distribution of the well-studied WLRG 3C 270 (NGC 4261) is ableto produce the observed emission-line ratios, but only if the UVemission seen by the narrow emission line gas is significantly higherthan that observed, implying AV=2.5-4.2 mag along our line ofsight to the nucleus. From the photoionization calculations, we findthat the emission-line gas must have an ionization parameter between10-3.5 and 10-4.0 and a wide range in hydrogendensity (102-106 cm-3) to reproduce themeasured emission-line ratios, similar to the properties inferred forthe emission-line gas in LINERs. Thus, we find that properties of theemission-line gas as well as the underlying excitation mechanism areindeed similar in LINERs and WLRGs. By extension, the central engines ofaccretion-powered LINERs and WLRGs, which do host an accreting blackhole, may be qualitatively similar.
| A new catalogue of ISM content of normal galaxies
We have compiled a catalogue of the gas content for a sample of 1916galaxies, considered to be a fair representation of ``normality''. Thedefinition of a ``normal'' galaxy adopted in this work implies that wehave purposely excluded from the catalogue galaxies having distortedmorphology (such as interaction bridges, tails or lopsidedness) and/orany signature of peculiar kinematics (such as polar rings,counterrotating disks or other decoupled components). In contrast, wehave included systems hosting active galactic nuclei (AGN) in thecatalogue. This catalogue revises previous compendia on the ISM contentof galaxies published by \citet{bregman} and \citet{casoli}, andcompiles data available in the literature from several small samples ofgalaxies. Masses for warm dust, atomic and molecular gas, as well asX-ray luminosities have been converted to a uniform distance scale takenfrom the Catalogue of Principal Galaxies (PGC). We have used twodifferent normalization factors to explore the variation of the gascontent along the Hubble sequence: the blue luminosity (LB)and the square of linear diameter (D225). Ourcatalogue significantly improves the statistics of previous referencecatalogues and can be used in future studies to define a template ISMcontent for ``normal'' galaxies along the Hubble sequence. The cataloguecan be accessed on-line and is also available at the Centre desDonnées Stellaires (CDS).The catalogue is available in electronic form athttp://dipastro.pd.astro.it/galletta/ismcat and at the CDS via anonymousftp to\ cdsarc.u-strasbg.fr (130.79.128.5) or via\http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/405/5
| The black hole mass of low redshift radiogalaxies
We make use of two empirical relations between the black hole mass andthe global properties (bulge luminosity and stellar velocity dispersion)of nearby elliptical galaxies, to infer the mass of the central blackhole (CM MBH) in low redshift radiogalaxies. Using the mostrecent determinations of black hole masses for inactive early typegalaxies we show that the bulge luminosity and the central velocitydispersion are almost equally correlated (similar scatter) with thecentral black-hole mass. Applying these relations to two large andhomogeneous datasets of radiogalaxies we find that they host black-holeswhose mass ranges from ~ 5*E7 to ~ 6*E9CMMsun (average ~ 8.9). CMMBH is found to be proportional to the mass of the bulge (CMMbulge). The distribution of the ratio CM MBH/CMMbulge has a mean value of 8*E-4 and shows ascatter that is consistent with that expected from the associatederrors. At variance with previous claims no significant correlation isinstead found between CM MBH (or CM Mbulge) andthe radio power at 5 GHz.
| Hi absorption in radio galaxies: effect of orientation or interstellar medium?
A search for Hi absorption has been made in 23 radio galaxies selectedfrom a complete sample. The observations were made with the AustraliaTelescope Compact Array (ATCA), with the Very Large Array (VLA) and forone galaxy with the Westerbork Synthesis Radio Telescope (WSRT). In fivegalaxies Hi absorption was detected. We investigate how the detectionrate is distributed among galaxies with different radio and opticalproperties. Among the Fanaroff-Riley (FR) type I radio galaxies, onlyone object (10 per cent of the total) was detected in Hi absorption. TheHi absorption in these objects is likely to come from a nuclear disc, asfound for other galaxies of this type (e.g. NGC 4261 and Hydra A). Thelow detection rate is consistent with the hypothesis (as suggested byoptical and X-ray data) that the `standard' parsec-scale, geometricallythick torus is not required in low-luminosity radio galaxies. This isconsistent with earlier optical work. In the case of FR type II powerfulradio galaxies, no Hi absorption has been detected in broad-line radiogalaxies, while three out of four narrow-line radio galaxies have beendetected (the one non-detection having quite a high upper limit). All ofthese are compact or small radio galaxies. To first order this isconsistent with the predictions of the unified schemes, assuming thatthe Hi absorption is caused by an obscuring torus. However, theindications of this being the only cause of the absorption are not verystrong. In particular, we find that in two of the three detected objectsthe Hi is blueshifted compared with the systemic velocity. In the thirdgalaxy (PKS 1549-79) two redshift systems (from the optical lines) arefound. The uncertainty in the systemic velocity derived from opticallines is discussed. Finally, by also considering data available in theliterature, we find a tendency for radio galaxies with a strongcomponent of young stellar population and far-infrared emission to showHi absorption. The overall richer interstellar medium that is likely tobe present in these galaxies may be a factor in producing theabsorption.
| New Evidence for the Unified Scheme of BL Lacertae Objects and FR I Radio Galaxies
In this paper, we collect radio and X-ray observations for mostFanaroff-Riley I (FR I) radio galaxies in the Zirbel-Baum radio galaxysample and investigate the distribution of the radio-to-X-ray effectivespectral index, αrx, to test the unified scheme of BLLac objects and FR I radio galaxies. It is found that the range ofαrx for FR I radio galaxies is almost the same as thatfor BL Lac objects, that the distribution of αrxprobably peaks at the same position as BL Lac objects, and that thedistribution of αrx for FR I galaxies is similar tothat for BL Lac objects. These suggest that there exist two subclassesof FR I radio galaxies: one is HBL-like, and the other is LBL-like,corresponding to high-energy-peaked (HBL) and low-energy-peaked (LBL) BLLac objects, respectively. This result is consistent with previous VLAobservations and supports the unified scheme of BL Lac objects and FR Iradio galaxies.
| Structure of the Clusters of Galaxies A 2634, A 1983, and DC 0428-53
The hierarchical and dynamical structure of three clusters of galaxies,A 2634, A 1983, and DC 0428-53, is investigated. Based on their example,we can say that the central cD galaxies play the leading role inclusters, affecting the course of their evolution. Radio and x-raygalaxies are not always part of the substructure. The morphologicalcomposition of various hierarchical subgroups depends on the stage ofevolution. Clusters have a tendency to be oriented in the directiontoward the nearest neighbor.
| Optical surface photometry of radio galaxies. II. Observations and data analysis
Optical imaging observations for 50 radio galaxies are presented. Foreach object isophotal contours, photometric profiles, structuralparameters (position angle, ellipticity, Fourier coefficients), andtotal magnitudes are given. These observations, obtained in the CousinsR band, complement the data presented in a previous paper and are partof a larger project aimed at studying the optical properties of lowredshift (z<= 0.12) radio galaxies (Govoni et al. 1999). Comments foreach individual source are reported.
| The optical properties of low redshift radio galaxies
We present morphological and photometric properties of 79 low redshift(z<=0.12) radio galaxies extracted from two radio flux limitedsamples of radio sources. All objects are imaged in the R band and for asubsample we have also obtained B band images. The sample includessources of both FRI and FRII radio morphological type. Through thedecomposition of the luminosity profiles and the analysis of thestructural profiles (ellipticity, PA, c4) of the galaxies we are able tocharacterize in detail the optical properties of the radio galaxies. Itis found that most of host galaxies are luminous bulge dominated systemssimilar to normal giant ellipticals. Some cases of additional diskcomponents are found whose spheroid-to-disk luminosity ratio is similarto that found in S0 galaxies. The average absolute magnitude is =-24.0 with a clear trend for FRI sources tobe ~ 0.5 mag brighter than FRII galaxies. In about 40% of the objectsobserved we find an excess of light in the nucleus that is attributed tothe presence of a nuclear point source whose luminosity is on average ~1-2% of the total flux of the host galaxy. The luminosity of thesenuclear point sources appears correlated with the core radio power ofthe galaxies. Radio galaxies follow the same mu_e - R_e relationship asnormal elliptical galaxies. The distribution of ellipticity, the amountof twisting and shape of isophotes (boxy, disky) do not differsignificantly from other ellipticals. The evidence for recentinteractions is therefore rather modest. Finally on average radiogalaxies are bluer and have a color dispersion larger than normalelliptical galaxies, and the average color gradient in radio galaxiesappears slightly steeper than in normal ellipticals. These resultssupport a scenario where radio emission is weakly related with theoverall properties and/or the activity have negligible effects on theglobal characteristics of the host galaxy. Based on observationscollected at the European Southern Observatory, La Silla, Chile. Basedon observations collected at the Nordic Optical Telescope, La Palma.
| Kinematics, abundances and origin of brightest cluster galaxies
We present kinematic parameters and absorption line strengths for threebrightest cluster galaxies, NGC 6166, 6173 and 6086. We find that NGC6166 has a velocity dispersion profile which rises beyond 20arcsec fromthe nucleus, with a halo velocity dispersion in excess of 400kms^-1. Allthree galaxies show a positive and constant h_4 Hermite moment. Therising velocity dispersion profile in NGC 6166 thus indicates anincreasing mass-to-light ratio. Rotation is low in all three galaxies,and NGC 6173 and 6086 show possible kinematically decoupled cores. Allthree galaxies have Mg_2 gradients similar to those found in normalbright ellipticals, which are not steep enough to support simpledissipative collapse models, but these could be accompanied bydissipationless mergers which would tend to dilute the abundancegradients. The [Mg/Fe] ratios in NGC 6166 and 6086 are higher than thatfound in NGC 6173, and if NGC 6173 is typical of normal brightellipticals, this suggests that cDs cannot form from late mergers ofnormal galaxies.
| An X-Ray and Optical Investigation of the Environments around Nearby Radio Galaxies
Investigations of the cluster environment of radio sources have notshown a correlation between radio power and degree of clustering.However, it has been demonstrated that extended X-ray luminosity andgalaxy clustering do exhibit a positive correlation. This studyinvestigates a complete sample of 25 nearby (z<=0.06) radio galaxiesthat are not cataloged members of Abell clusters. The environment ofthese radio galaxies is studied in both the X-ray and the optical bymeans of the ROSAT All-Sky Survey (RASS), ROSAT pointed observations,and the Palomar optical Digitized Sky Survey (DSS). X-ray luminositiesand extents are determined from the RASS, and the DSS is used toquantify the degree of clustering via the spatial two-point correlationcoefficient, Bgg. Of the 25 sources, 20 are >=3 σdetections in the X-ray and 11 possessed Bgg's significantlyin excess of that expected for an isolated galaxy. Adding the criterionthat the X-ray emission be resolved, 10 of the radio galaxies do appearto reside in poor clusters with extended X-ray emission suggestive ofthe presence of an intracluster medium. Eight of these galaxies alsopossess high spatial correlation coefficients. Taken together, thesedata suggest that the radio galaxies reside in a low-richness extensionof the Abell clusters. The unresolved X-ray emission from the othergalaxies is most likely associated with active galactic nucleusphenomena. Furthermore, although the sample size is small, it appearsthat the environments of FR I and FR II sources differ. FR I's tend tobe more frequently associated with extended X-ray emission (10 of 18),whereas FR II's are typically point sources or nondetections in theX-ray (none of the seven sources exhibit extended X-ray emission).
| Properties of the ROSAT selected radio sources. I. The sample.
Not Available
| The nature of the optical-radio correlations for powerful radio galaxies
The nature of the optical-radio correlations for powerful radio galaxiesis investigated using spectroscopic observations of a complete sample ofsouthern 2-Jy radio sources. In line with previous work, we find thatsignificant correlations exist between the luminosities of the[OIII]lambda5007, [OII]lambda3727 and Hβ emission lines and the radioluminosity. However, our observations are not easily reconciled with theidea that these correlations are caused by the increase in the power ofthe photoionizing quasar as the jet power increases, with average ISMproperties not changing appreciably with redshift or radio power: notonly do we find that the scatter in the L_[Oiii] versus L_radiocorrelation is significantly larger than in L_[Oii] versus L_radio andL_Hβ versus L_radio correlations, but the ionization state deducedfrom the emission lines does not increase with radio power as predictedby the simple, constant ISM, photoionization model. We conclude that (a)there exists a considerable range in the quasar ionizing luminosity at agiven redshift, and (b) the mean density of the emission-line clouds islarger in the high-redshift/high-power radio sources. The latter densityenhancement may be either a consequence of the increased importance ofjet-cloud interactions or, alternatively, the result of a higherpressure in the confining hot ISM, in the high-redshift objects. Apartfrom the general scatter in the correlations, we identify a distinctgroup of objects with [OIII]lambda5007 luminosities which are more thanan order of magnitude lower than in the general population radiogalaxies at similar redshift. These weak-line radio galaxies (WLRGs) arelikely to be sources in which the central ionizing quasars areparticularly feeble. Deep spectra show that many of the sources in oursample are broad-line radio galaxies (BLRGs). The fact that the BLRGsare observed out to the redshift limit of the survey, overlapping inredshift with the quasars, argues against the idea that BLRGs are simplythe low-radio-power counterparts of high-power, high-redshift quasars.Either there exists a considerable range in the intrinsic luminositiesof the broad-line AGN for a given redshift or radio power, or the BLRGsrepresent partially obscured quasars. The degree of scatter present inthe L_[Oiii] versus L_radio correlation supports the former possibility.
| 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 study of cores in a complete sample of radio sources
The high resolution provided by the Parkes-Tidbinbilla real-timeinterferometer (PTI) has been used to measure the core flux density fora complete sample of radio sources. Lower resolution maps are alreadyavailable for most of these objects together with optical(spectroscopic) data. The new data show that an inverted spectral indexalpha~-0.3 (S~nu^-alpha) could be characteristic of all the nuclei,going from low-luminosity radio galaxies to powerful quasars. Takingthis spectral index into account, the measured flux density does notchange very much, going from a scale of tens of kpc (corresponding tothe low-resolution observations) to the sub-kpc scale of the newobservations. Thus, most of the flux observed in the central regionoriginates in a sub-kpc area. With the new PTI data we obtain a betterestimate of the radio core dominance (R), i.e. the ratio between thecore and the extended radio flux. This parameter is claimed to be a goodindicator of the orientation of the beamed radiation with respect to theline of sight, and hence a very important parameter for testing `unifiedschemes' for active galactic nuclei (AGN). Using this parameter,together with optical spectroscopic information, we find that the radiocore dominance shows different distributions for different radio andoptical characteristics. A statistically significant difference in thedistribution of R is observed between Fanaroff-Riley (FR) I and FR IIradio galaxies, supporting the idea that low-power sources are lessaffected by beaming because they have, on average, a lower Lorentzfactor. Among the FR II radio galaxies, narrow-line radio galaxies(NLRGs) show lower values of R while the broad-line radio galaxies(BLRGs) have the largest R. Moreover, the median value of R for BLRGs islower than for steep-spectrum quasars (SSQ) even after a number ofselection effects are taken into account. This result can be explainedin the framework of unified schemes for AGN assuming that in the BLRGswe are seeing more directly into the nucleus, although not as much as inSSQs.
| The fundamental plane of early-type galaxies: stellar populations and mass-to-light ratio.
We analyse the residuals to the fundamental plane (FP) of ellipticalgalaxies as a function of stellar-population indicators; these are basedon the line-strength parameter Mg_2_ and on UBVRI broad-band colors, andare partly derived from new observations. The effect of the stellarpopulations accounts for approximately half the observed variation ofthe mass-to-light ratio responsible for the FP tilt. The residual tiltcan be explained by the contribution of two additional effects: thedependence of the rotational support, and possibly that of the spatialstructure, on the luminosity. We conclude to a constancy of thedynamical-to-stellar mass ratio. This probably extends to globularclusters as well, but the dominant factor would be here the luminositydependence of the structure rather than that of the stellar population.This result also implies a constancy of the fraction of dark matter overall the scalelength covered by stellar systems. Our compilation ofinternal stellar kinematics of galaxies is appended.
| A Catalog of Stellar Velocity Dispersions. II. 1994 Update
A catalog of central velocity dispersion measurements is presented,current through 1993 September. The catalog includes 2474 measurementsof 1563 galaxies. A standard set of 86 galaxies is defined, consistingof galaxies with at least three reliable, concordant measurements. It issuggested that future studies observe some of these standard galaxies sothat different studies can be normalized to a consistent system. Allmeasurements are reduced to a normalized system using these standards.
| The optical identification status of the 1 Jy radio source catalogue
Optical identifications, magnitudes, redshifts, and polarization datahave been gathered from an extensive literature search to form an updateof the optical data for the radio sources of the 1 Jy catalogue. Of the527 radio sources in the revised catalogue, 97% have opticalcounterparts, and redshifts are given for 90% of the opticallyidentified sources. For all but a few sources, accurate interferometerradio position are provided. References are made to well knowncompilations as well as to individual papers, often supplemented byspecial notes on individual objects.
| The Radio Structures of Southern 2-JY Radio Sources
A subsample of the Wall & Peacock 2-Jy sample of radio sources, withredshift z < 0.7 or unknown and declination δ < + 10^deg^,has been selected and observed in the radio at 6 cm (or information wasobtained from the literature where appropriate) and in the optical withlow- dispersion spectroscopy. Here we present the new radio data. Weobserved 66 sources with the Very Large Array and seven southern sourceswith the Australia Telescope Compact Array. Together with the datacollected from the literature, we now have information about the radiostructure of 107 sources. These data will be discussed along withoptical spectra for the sample in a future paper.
| Optical Spectroscopy of a Complete Sample of Southern 2-JY Radio Sources
We present optical spectra for a complete sample of radio galaxies andquasars comprising all sources from the Wall & Peacock 2.7-GHzsample with redshifts z < 0.7 and declinations δ < +10^deg^; this sample is complete down to a flux density of 2 Jy.Although not all of the 2-Jy sources have spectroscopic redshifts, weargue that most of the unidentified objects are at high redshifts andthat our z < 0.7 sample is largely complete. The optical data will beanalysed in a future paper.
| The structure of southern extragalactic radio sources
The structure of extragalactic radio sources south of declination -30deg that have been imaged at 843 MHz with a resolution of 44 arcsec isreported. The sample includes sources noted in the Molonglo ReferenceCatalogue (MRC) as extended (larger than about 1 arcmin), as well asthose noted as multiple, i.e., within 8 arcmin of a neighbor andpossibly related. The results of observations of 339 sources with eithertime-shared or full 12-hr aperture-synthesis observations are given asradio images and a table of flux densities, positions, and sizes for 383sources. Most of the groups of multiple sources are found to beseparate, unrelated sources, as expected, but some are components oflarger sources. Some of the sources flagged as extended in the MRC arealso groups of unrelated sources, confused in the MRC beam. Such randomassociates are excluded, and a confirmed MRC extended sample of 193sources with flux density greater than 0.4 Jy and size greater than 0.5arcmin is confirmed. The selection effects and completeness for thissample are discussed.
| Flux densities at 8400 MHz for a large sample of radio sources
This paper presents 8400-MHz flux densities for 1194 southern radiosources. The sources were selected from the Parkes 2700-MHz Survey toinclude all those stronger than 0.5 Jy at that survey's findingfrequency of 2700 MHz. The new fluxes have an accuracy of about 8percent, corresponding to 0.05 Jy for a typical source. It isanticipated that the data will be useful in defining the high-frequencyradio spectra of many sources as well as in pinpointing objects withwhich to improve the southern, astrometric absolute reference frame.
| The plane W(Na I) X W(Mg I) - Effects of interstellar Na I in a sample of southern galaxies
Galaxy spectra from a subsample of the Southern Sky Redshift Survey databank were used to study the equivalent width plane for the lines Na Ilambda 5893 A vs Mg I lambda 5175 A. An estimate of how important thecontribution of the interstellar gas for the sodium line is compared tothat of the stellar population. The sample is made up of galaxies withmorphological types from E to Sc and are distributed up to radialvelocities of 25,000 km/s, most of them smaller than 15,000 km/s. Mostearly type galaxies with dust lanes, particularly nearly edge-on So's,present an enhancement of the Na I line. Inclined spiral galaxies tendto present enhanced Na I with respect to face-on spirals. This tendency,previously found in a smaller sample of galaxies limited to V equal toor less than 6000 km/s, is now confirmed for more distant ones. In thelarge velocity sample it shows the global bulge rather than the verynucleus; the persistence of the effect suggests that the scale height ofthe gas layer in the central disk can reach a considerable fraction ofthe bulge radius.
| The stellar content of central dominant galaxies. I - CCD surface photometry
UBVRI CCD surface photometry and color gradients are presented for 10central dominant galaxies (CDGs), comprising gE, D, and cD morphologicaltypes and covering the range of Bautz-Morgan cluster types. The meanmagnitude of the color gradients to a radius of 20 kpc is in agreementwith those found in recent CCD studies of bright ellipticals in Virgo.The size of the gradients are consistent with N-body model predictionsin which these galaxies are formed or enhanced by merger events.Parameters such as ellipticity, position angle of the major axis, anddeviation from ellipticity for eight single-nucleus CDGs are also given.All galaxies show large changes in ellipticity and position angle withradius, and can be considered similar to Kormendy's T3 class ofgalaxies, in which tidal effects on isophotal structure are veryprobable. Three out of eight single-nucleus CDGs, NGC 1399, NGC 6876 andIC 1860, show evidence of isochromal flattening inside 10 kpc. Five(three boxy, two disk) out of the eight single-nucleus CDGs displaynonelliptical isophotes.
| A catalogue of Seyfert galaxies.
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