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Ýlgili Makaleler
Local and Large-Scale Environment of Seyfert Galaxies
We present a three-dimensional study of the local (<=100h-1 kpc) and the large-scale (<=1 h-1 Mpc)environment of the two main types of Seyfert AGN galaxies. For thispurpose we use 48 Seyfert 1 galaxies (with redshifts in the range0.007<=z<=0.036) and 56 Seyfert 2 galaxies (with0.004<=z<=0.020), located at high galactic latitudes, as well astwo control samples of nonactive galaxies having the same morphological,redshift, and diameter size distributions as the corresponding Seyfertsamples. Using the Center for Astrophysics (CfA2) and Southern SkyRedshift Survey (SSRS) galaxy catalogs (mB~15.5) and our ownspectroscopic observations (mB~18.5), we find that within aprojected distance of 100 h-1 kpc and a radial velocityseparation of δv<~600 km s-1 around each of ourAGNs, the fraction of Seyfert 2 galaxies with a close neighbor issignificantly higher than that of their control (especially within 75h-1 kpc) and Seyfert 1 galaxy samples, confirming a previoustwo-dimensional analysis of Dultzin-Hacyan et al. We also find that thelarge-scale environment around the two types of Seyfert galaxies doesnot vary with respect to their control sample galaxies. However, theSeyfert 2 and control galaxy samples do differ significantly whencompared to the corresponding Seyfert 1 samples. Since the maindifference between these samples is their morphological typedistribution, we argue that the large-scale environmental differencecannot be attributed to differences in nuclear activity but rather totheir different type of host galaxies.
| Water-Vapor Maser Survey for Active Galactic Nuclei: A Megamaser in NGC 6926
We made a survey of water-vapor maser emission for 93 AGNs with theNobeyama 45-m and Mopra 22-m telescopes from 1999 to 2002. A megamaserwas detected in a Seyfert 2 galaxy, NGC 6926, at a distance of 80Mpc, in2002 June. [Greenhill et al. (2003a) have also reported a detection ofthe megamaser at the close date.] The peak flux density was 110mJy, andthe total isotropic luminosity was 340 Lȯ. The masershows triply peaked spectrum, suggesting an edge-on disk. A narrow-linefeature of the maser components at VLSR = 6001 kms-1 was strongly variable with a time scale of a few tens ofdays, and the variation should be of intrinsic origin. We also showed apossibility of variability of water-vapor maser emission of a megamaserpreviously detected in a Seyfert/ultraluminous FIR galaxy, NGC 6240.
| An atlas of calcium triplet spectra of active galaxies
We present a spectroscopic atlas of active galactic nuclei covering theregion around the λλ8498, 8542, 8662 calcium triplet(CaT). The sample comprises 78 objects, divided into 43 Seyfert 2s, 26Seyfert 1s, three starburst and six normal galaxies. The spectra pertainto the inner ~300 pc in radius, and thus sample the central kinematicsand stellar populations of active galaxies. The data are used to measurestellar velocity dispersions (σ*) with bothcross-correlation and direct fitting methods. These measurements arefound to be in good agreement with each other and with those in previousstudies for objects in common. The CaT equivalent width is alsomeasured. We find average values and sample dispersions ofWCaT of 4.6 +/- 2.0, 7.0 +/- 1.0 and 7.7 +/- 1.0 Å forSeyfert 1s, Seyfert 2s and normal galaxies, respectively. We furtherpresent an atlas of [SIII]λ9069 emission-line profiles for asubset of 40 galaxies. These data are analysed in a companion paperwhich addresses the connection between stellar and narrow-line regionkinematics, the behaviour of the CaT equivalent width as a function ofσ*, activity type and stellar population properties.
| Dark matter in the inner parts of barred galaxies: The data
This paper presents surface photometry (B,V,I,J,H,K) and Hαrotation curves of 27 isolated spiral galaxies. The final goal is toobtain the mass distribution of a sample of isolated spiral galaxies inorder to model their gas kinematics. This is then compared to theobserved rotation curve, to determine the necessity of a dark halo inthe inner parts (Perez et al. 2004, A&A, 424, 799). The azimuthallyaveraged radial surface brightness profiles and the integratedmagnitudes obtained from ellipse fitting are given for each of thesample galaxies. The ellipse fitting technique applied to the lightdistribution also allowed us to obtain the size of the bar, and theinclination and position angle of the outer isophotes that allow thegalaxy deprojection. Using these profiles, 1-D disk-bulge decompositionwas performed to obtain the disk scale-length and the bulge effectiveradius for the different bands. Through the fitting of a parametricfunction to the observed rotation curve, the maximum rotational velocityand the corresponding radius was obtained. The correlation between thebulge and disk parameters is in agreement with previous studies (de Jong1996a, A&A, 313, 45; Márquez & Moles 1999, A&A, 344,421; Baggett et al. 1998, AJ, 116, 1626). Regarding the Kormendyrelation (Kormendy 1977, ApJ, 218, 333), in agreement with de Jong, nocorrelation between the bulge effective radius and its surfacebrightness is found, possibly due to the small range of bulge magnitudescovered. We find a smaller scatter in the structural relations whencompared to non-isolated samples in agreement with Márquez &Moles (1999). Finally, a correlation between the disk scale-length andthe bar size is observed, possibly reflecting the rapid growth of a bar.
| The ISOPHOT 170 μm Serendipity Survey II. The catalog of optically identified galaxies%
The ISOPHOT Serendipity Sky Survey strip-scanning measurements covering≈15% of the far-infrared (FIR) sky at 170 μm were searched forcompact sources associated with optically identified galaxies. CompactSerendipity Survey sources with a high signal-to-noise ratio in at leasttwo ISOPHOT C200 detector pixels were selected that have a positionalassociation with a galaxy identification in the NED and/or Simbaddatabases and a galaxy counterpart visible on the Digitized Sky Surveyplates. A catalog with 170 μm fluxes for more than 1900 galaxies hasbeen established, 200 of which were measured several times. The faintest170 μm fluxes reach values just below 0.5 Jy, while the brightest,already somewhat extended galaxies have fluxes up to ≈600 Jy. For thevast majority of listed galaxies, the 170 μm fluxes were measured forthe first time. While most of the galaxies are spirals, about 70 of thesources are classified as ellipticals or lenticulars. This is the onlycurrently available large-scale galaxy catalog containing a sufficientnumber of sources with 170 μm fluxes to allow further statisticalstudies of various FIR properties.Based on observations with ISO, an ESA project with instruments fundedby ESA Member States (especially the PI countries: France, Germany, TheNetherlands and the UK) and with the participation of ISAS and NASA.Members of the Consortium on the ISOPHOT Serendipity Survey (CISS) areMPIA Heidelberg, ESA ISO SOC Villafranca, AIP Potsdam, IPAC Pasadena,Imperial College London.Full Table 4 and Table 6 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/422/39
| HYPERLEDA. II. The homogenized HI data
After a compilation of HI data from 611 references and new observationsmade in Nançay, we produce a catalog of homogenized HI data for16781 galaxies. The homogenization is made using the EPIDEMIC methodfrom which all data are progressively converted into the adoptedstandard. The result is a catalog giving: 1) the logarithm of twice themaximum rotation velocity, log 2V_Msin i, converted to thesystem of Mathewson et al. (\cite{Mathewson1996}). This quantity isgiven without correction for inclination; 2) the HI magnitude,m21, (area of the 21-cm line width expressed in magnitude)converted to the flux system of Theureau et al. (\cite{Theureau1998});3) the HI velocity, V_HI, expressed with the optical definition (i.e.,using wavelengths instead frequencies). The typical uncertainties are:0.04 for log 2V_Msin i, 0.25 mag for m21 and 9 kms-1 for V_HI.Full Tables \ref{epidemicw}, \ref{epidemicw2}, \ref{epidemicf},\ref{epidemicf2} and Fig. \ref{profiles} are available in electronicform at http://www.edpsciences.org. Full Tables \ref{references},\ref{cataf}, \ref{newdata} and \ref{notes} are available in electronicform at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/412/57
| High-resolution radio observations of Seyfert galaxies in the extended 12-μm sample - II. The properties of compact radio components
We discuss the properties of compact nuclear radio components in Seyfertgalaxies from the extended 12-μm AGN sample of Rush et al. Our mainresults can be summarized as follows. Type 1 and type 2 Seyferts producecompact radio components which are indistinguishable in strength andaspect, indicating that their central engines are alike, as proposed bythe unification model. Infrared IRAS fluxes are more closely correlatedwith low-resolution radio fluxes than high-resolution radio fluxes,suggesting that they are dominated by kiloparsec-scale, extranuclearemission regions; extranuclear emission may be stronger in type 2Seyferts. Early-type Seyfert galaxies tend to have stronger nuclearradio emission than late-type Seyfert galaxies. V-shaped extendedemission-line regions, indicative of `ionization cones', are usuallyfound in sources with large, collimated radio outflows. Hidden broadlines are most likely to be found in sources with powerful nuclear radiosources. Type 1 and type 2 Seyferts selected by their IRAS 12-μm fluxdensities have well-matched properties.
| Stellar populations in Seyfert 2 galaxies. I. Atlas of near-UV spectra
We have carried out a uniform spectroscopic survey of Seyfert 2 galaxiesto study the stellar populations of the host galaxies. New spectra havebeen obtained for 79 Southern galaxies classified as Seyfert 2 galaxies,7 normal galaxies, and 73 stars at a resolution of 2.2 Å over thewavelength region 3500-5300 Å. Cross-correlation between thestellar spectra is performed to group the individual observations into44 synthesis standard spectra. The standard groups include a solarabundance sequence of spectral types from O5 to M3 for dwarfs, giants,and supergiants. Metal-rich and metal-weak F-K giants and dwarfs arealso included. A comparison of the stellar data with previouslypublished spectra is performed both with the individual spectra and thestandard groups. For each galaxy, two distinct spatial regions areconsidered: the nucleus and the external bulge. Spectroscopic variationsfrom one galaxy to another and from the central to the external regionare briefly discussed. It is found that the central region of a Seyfert2 galaxy, after subtracting the bulge stellar population, always shows anear-UV spectrum similar to one of three representative categories: a)many strong emission lines and only two visible absorption lines (Ca IiK and G band) (Sey2e); b) few emission lines, many absorption lines, anda redder continuum than the previous category (Sey2a); c) an almost flatcontinuum and high-order Balmer lines seen in absorption (Sey2b). Theproportion of Seyfert 2 galaxies belonging to each class is found to be22%, 28%, and 50% respectively. We find no significative differencesbetween morphology distributions of Seyfert 2 galaxies with Balmer linesdetected in absorption and the rest of the sample. This quick lookthrough the atlas indicates that half of Seyfert 2 galaxies harbour ayoung stellar population (about or less than 100 Myr) in their centralregion, clearly unveiled by the high order Balmer series seen inabsorption. Based on observations collected at the European SouthernObservatory, Chile (ESO 65.P-0014(A)). Tables 1-3 and 8 and Fig. A.1(Appendix A) are only available in electronic form athttp://www.edpsciences.org
| Jet Directions in Seyfert Galaxies: B and I Imaging Data
We present the results of broadband B and I imaging observations for asample of 88 Seyfert galaxies (29 Seyfert 1s and 59 Seyfert 2s),selected from a mostly isotropic property, the flux at 60 μm. We alsopresent the B and I imaging results for an additional sample of 20Seyfert galaxies (7 Seyfert 1s and 13 Seyfert 2s), selected from theliterature and known to have extended radio emission. The I-band imagesare fitted with ellipses to determine the position angle and ellipticityof the host galaxy major axis. This information will be used in a futurepaper, combined with information from radio observations, to study theorientation of radio jets relative to the planes of their host galaxies.Here we present surface brightness profiles and magnitudes in the B andI bands, as well as mean ellipticities and major axis position angles.
| Jet Directions in Seyfert Galaxies
Here we present the study of the relative angle between the accretiondisk (or radio jet) and the galaxy disk for a sample of Seyfert galaxiesselected from a mostly isotropic property, the 60 μm flux, and warminfrared colors. We used VLA A-array 3.6 cm continuum data andground-based optical imaging, homogeneously observed and reduced tominimize selection effects. For parts of the analysis we enlarged thesample by including galaxies serendipitously selected from theliterature. For each galaxy we have a pair of points (i, δ), whichare the inclination of the galaxy relative to the line of sight and theangle between the jet projected into the plane of the sky and the hostgalaxy major axis, respectively. For some galaxies we also hadinformation about which side of the minor axis is closer to Earth. Thisdata is combined with a statistical technique, developed by us, todetermine the distribution of β angles in three dimensions, theangle between the jet and the host galaxy plane axis. We found from aninitial analysis of the data of the 60 μm sample, where Seyfert 1 and2 galaxies were not differentiated, that the observed distribution of iand δ values can be well represented either by a homogeneoussinβ distribution in the range0deg<=β<=90deg or in0deg<=β<=65deg, but not by anequatorial ring. A more general model, which tested β-distributionsin the range β1<=β<=β2, fordifferent ranges of β1 and β2 values,required β2 to be larger than 65° and gavepreference for β1 smaller than 40°-50°. Animportant result from our analysis was obtained when we determinedwhether the jet was projected against the near or the far side of thegalaxy and differentiated between Seyfert 1 and Seyfert 2 galaxies,which showed that the model could not represent Seyfert 1 galaxiesadequately. We found that the inclusion of viewing angle restrictionsfor Seyfert 1 galaxies, namely, that a galaxy can be recognized as aSeyfert 1 only if the angle between the jet and the line of sight(|φ|) is smaller than a given angle φc and that thegalaxy inclination i is smaller than an angle ic, gave riseto statistically acceptable models. This indication that there is adifference in viewing angle to the central engine between Seyfert 1galaxies and Seyfert 2 galaxies is a direct and independent confirmationof the underlying concepts of the unified model. We discuss possibleexplanations for the misalignment between the accretion disk and thehost galaxy disk: warping of the accretion disk by self-irradiationinstability, by the Bardeen-Petterson effect, or by a misalignedgravitational potential of a nuclear star cluster surrounding the blackhole, as well as feeding of the accretion disk by a misaligned inflow ofgas from minor mergers, capture of individual stars or gas from thenuclear star cluster, and the capture of individual molecular cloudsfrom the host galaxy.
| Radio Structures of Seyfert Galaxies. VIII. A Distance- and Magnitude-Limited Sample of Early-Type Galaxies
The VLA has been used at 3.6 and 20 cm to image a sample of about 50early-type Seyfert galaxies with recessional velocities less than 7000km s^-1 and total visual magnitude less than 14.5. Emission-line ([OIII] and Hα+[N II]) and continuum (green and red) imaging of thissample has been presented in a previous paper. In this paper, we presentthe radio results, discuss statistical relationships between the radioand other properties, and investigate these relationships within thecontext of unified models of Seyferts. The mean radio luminosities ofearly-type Seyfert 1's (i.e., Seyfert 1.0's, 1.2's, and 1.5's) and 2.0'sare found to be similar (consistent with the unified scheme), and theradio luminosity is independent of morphological type within thissample. The fraction of resolved radio sources is larger in the Seyfert2.0's (93%) than in the Seyfert 1's (64%). However, the mean radioextents of Seyfert 2.0's and 1's are not significantly different,although this result is limited by the small number of resolved Seyfert1's. The nuclear radio structures of Seyfert 2.0's in the early-typesample tend to be aligned with the [O III] and Hα+[N II]structures, even though the radio extents are smaller than the [O III]and Hα+[N II] extents by a factor of ~2 to more than 5. Thisalignment, previously known for individual Seyferts with ``linear''radio sources, is here shown to be characteristic of early-type Seyfertgalaxies as a class. Seyfert 2.0's in the early-type sample also show asignificant alignment between the emission-line ([O III] and Hα+[NII]) axes and the major axis of the host galaxy. These alignments areconsistent with a picture in which the ionized gas represents ambientgas predominantly coplanar with the galaxy stellar disk. This ambientgas is ionized by nuclear radiation that may escape preferentially alongand around the radio axis, and is compressed in shocks driven by theradio ejecta. We use this alignment to constrain the product of thevelocity of the radio ejecta and the period of any large-angleprecession of the inner accretion disk and jet: V_ejectaxP>=2 kpc. Aninvestigation of a larger sample of Seyferts reveals the unexpectedresult that the Seyfert 1's with the largest radio extent (>=1.5 kpc)are all of type Seyfert 1.2. It appears that classification as this typeof intermediate Seyfert depends on some factor other than the relativeorientation of the nuclear-obscuring torus to the line of sight. Amongall the other Seyferts, the distribution of radio extent with Seyfertintermediate type is consistent with the expectations of the unifiedscheme.
| The Relative Orientation of Nuclear Accretion and Galaxy Stellar Disks in Seyfert Galaxies
We use the difference (delta) between the position angles of the nuclearradio emission and the host galaxy major axis to investigate thedistribution of the angle (beta) between the axes of the nuclearaccretion disk and the host galaxy disk in Seyfert galaxies. We providea critical appraisal of the quality of all measurements, and find thatthe data are limited by observational uncertainties and biases, such asthe well known deficiency of Seyfert galaxies of high inclination. Thereis weak evidence that the distribution of delta for Seyfert 2 galaxiesmay be different (at the 90% confidence level) from a uniformdistribution, while the Seyfert 1 delta distribution is notsignificantly different from a uniform distribution or from the Seyfert2 delta distribution. The cause of the possible nonuniformity in thedistribution of delta for Seyfert 2 galaxies is discussed. Seyfertnuclei in late-type spiral galaxies may favor large values of delta (atthe ~96% confidence level), while those in early-type galaxies show amore or less random distribution of delta. This may imply that thenuclear accretion disk in noninteracting late-type spirals tends toalign with the stellar disk, while that in early-type galaxies is morerandomly oriented, perhaps as a result of accretion following a galaxymerger. We point out that biases in the distribution of inclinationtranslate to biased estimates of beta in the context of the unifiedscheme. When this effect is taken into account, the distributions ofbeta for all Seyferts together, and of Seyfert 1s and 2s separately,agree with the hypothesis that the radio jets are randomly oriented withrespect to the galaxy disk. The data are consistent with theexpectations of the unified scheme, but do not demand it.
| The Southern Sky Redshift Survey
We report redshifts, magnitudes, and morphological classifications for5369 galaxies with m_B <= 15.5 and for 57 galaxies fainter than thislimit, in two regions covering a total of 1.70 sr in the southerncelestial hemisphere. The galaxy catalog is drawn primarily from thelist of nonstellar objects identified in the Hubble Space TelescopeGuide Star Catalog (GSC). The galaxies have positions accurate to ~1"and magnitudes with an rms scatter of ~0.3 mag. We compute magnitudes(m_SSRS2) from the relation between instrumental GSC magnitudes and thephotometry by Lauberts & Valentijn. From a comparison with CCDphotometry, we find that our system is homogeneous across the sky andcorresponds to magnitudes measured at the isophotal level ~26 magarcsec^-2. The precision of the radial velocities is ~40 km s^-1, andthe redshift survey is more than 99% complete to the m_SSRS2 = 15.5 maglimit. This sample is in the direction opposite that of the CfA2; incombination the two surveys provide an important database for studies ofthe properties of galaxies and their large-scale distribution in thenearby universe. Based on observations obtained at Cerro TololoInter-American Observatory, National Optical Astronomy Observatories,operated by the Association of Universities for Research in Astronomy,Inc., under cooperative agreement with the National Science Foundation;Complejo Astronomico El Leoncito, operated under agreement between theConsejo Nacional de Investigaciones Científicas de laRepública Argentina and the National Universities of La Plata,Córdoba, and San Juan; the European Southern Observatory, LaSilla, Chile, partially under the bilateral ESO-ObservatórioNacional agreement; Fred Lawrence Whipple Observatory;Laboratório Nacional de Astrofísica, Brazil; and the SouthAfrican Astronomical Observatory.
| Large-Scale Outflows in Edge-on Seyfert Galaxies. I. Optical Emission-Line Imaging and Optical Spectroscopy
We have launched a search for large-scale (>1 kpc) minor axisoutflows in edge-on Seyfert galaxies in order to assess their frequencyof occurrence and to study their properties. Here we present opticalcontinuum and Hα + [N II] line images and/or minor axis long-slitspectra of 22 edge-on Seyfert galaxies. Six of these galaxies show atleast one of the following: (i) bi-symmetric Hα halos extendingalong the minor axis, (ii) bright emission-line complexes at distances> 4 kpc (in projection) out of the disk, and (iii) double-peakedemission- line profiles from the gas along the minor axis, suggestingthat a windblown bubble is present. Our results indicate that > 1/4of Seyfert galaxies have good evidence for minor axis galactic outflows.Kinetic luminosities of the galactic outflows in our sample Seyfertgalaxies are ~10^40^-10^42^ ergs s^-1^, assuming all the observed minoraxis emission is produced by the outflow. These values are, in general,~0.1 as large as those well-studied cases of superwinds in starburstgalaxies (Heckman, Armus, & Miley 1990). However, far-infraredluminosities of our sample Seyfert galaxies are also ~0.1 as large. Bothstarburst-driven superwinds and wide-angled outflows from the activegalactic nucleus are possible explanations for the observed large-scaleoutflows.
| An Emission-Line Imaging Survey of Early-Type Seyfert Galaxies. I. The Observations
Flux-calibrated images in the lines of [O III] λ5007 and Hα+ [N II] λλ6548, 6583 and the nearby continuum arepresented for 57 Seyfert galaxies of early morphological type. Thissample includes all known Seyfert galaxies with apparent magnitude m_v_<= 14.5 and recessional velocity cz < 7000 km s^-1^ in Hubbletypes E, S0, and S0/a. Images are also presented for an additional 26galaxies with m_v_ > 14.5, cz > 7000 km s^-1^, and/or an uncertainclassification as a Seyfert galaxy. The ratio of the [O III]λ5007 to the Hα + [N II] image has been obtained for eachgalaxy with extended emission to study the spatial variation of thegaseous excitation. Maps of the V - R color distributions over thegalaxies are also presented.
| An Emission-Line Imaging Survey of Early-Type Seyfert Galaxies. II. Implications for Unified Schemes
We report simulations of emission-line morphologies and results of alarge imaging survey of a complete sample of Seyfert galaxies in early-type hosts in the emission lines of [O III] λ5007 and Hα +[N III] λλ6548, 6583 and the nearby continua. Thesesimulations and observations are compared in order to test models inwhich the apparent Seyfert class depends on the orientation of theactive nucleus with respect to the observer. In unified models, theactive nucleus is surrounded by a thick, dusty gaseous torus. Thenuclear ionizing radiation is then expected to escape in oppositelydirected cones along the axis of the torus. We have, therefore,performed simulations in which ambient gas is ionized by a bi-conicalradiation field. When the ambient gas is distributed in a sphere orspheroid, V- shaped projections are expected whenever our line of sightis outside the cones of ionizing radiation. For line of sights withinthe cones, "halo"-like morphologies are produced. For such gasdistributions, the measured opening angle of the V-shaped morphology isequal to or larger than the true opening angle of the radiation field.On the other hand, when the gas is distributed in a thin disk, V-shapedprojections are produced the majority of the time, even when our line ofsight is within the photon cone. The measured opening angle in the caseis usually smaller than the true opening angle of the photon cone. Forboth spherical and thin disk gas distributions, the projected linearextent of the ionized gas tends to be smaller for lines of sight withinthe cones. From the emission-line images, we find that extendedemission-line gas is very common in Seyfert galaxies, with ~80% of thegalaxies showing extension in our [O III] λ5007 images and ~100%showing extension in Hα + [N II]. The percentage of galaxiesextended in these lines is comparable for Seyfert 1s and 2s. There is astrong correlation between the line fluxes of the unresolved core andthe extended emission, suggesting the extended emission is ionized bythe same source that ionizes the nuclear gas. There is also acorrelation between emission- line extent and luminosity. The total [OIII] λ5007 luminosities of the Seyfert 1s in our sample aresimilar to those of the Seyfert 2s, while the total Hα + [N II]emission is larger in Seyfert 1s than Seyfert 2s. This result is notsurprising since the broad component to the Hα line contributes asignificant amount of flux in the Seyfert 1s. In order to compare theextended emission-line luminosities of the two Seyfert types, we havesubtracted an unresolved nuclear component from the images. We find atrend for the extended emission in both [O III] λ5007 andHα + [N II] to be more luminous in the Seyfert 1s than the Seyfert2s. However, this trend is of only marginal significance in the completesample. In general, it is difficult, if not impossible, to distinguish aSeyfert 1 galaxy from a Seyfert 2 galaxy based only on its emission-linecharacteristics. While linear, bipolar, or V-shaped morphologies areseen in some objects, for one-third of the sample the emission-linestructures are "halo "-like. These "halo" morphologies are not expectedfor Seyfert 2s in the unified model. Many of the "halo" Seyfert 2s dodisplay linear or V-shaped structures in their excitation maps (i.e.,distributions of [O III]/Hα + [N II]), so they may still beconsistent with orientation - dependent models. However, theemission-line morphologies of at least a few Seyfert 1s appearinconsistent with those expected in the simplest unified schemes. In ourcomplete sample, the extent of the [O III] λ5007 emission at agiven surface brightness is larger in the Seyfert 2s than the Seyfert1s. However, this difference disappears if the two most extended Seyfert2s are omitted. We also find evidence for structure in many of thecontinuum color maps. In ~40% of the galaxies with color maps, red (V -R > 1.0) features are found. The majority of these red regions areunresolved structures located at the nucleus. These features are foundin galaxies of all inclinations, but occur almost exclusively in type 2Seyfert galaxies. These characteristics are consistent with reddening by~100 pc scale, dusty tori. A less likely alternative is that thesestructures represent a very red stellar population (later than K5).Diffuse blue (V - R < 0.5) features are seen in some Seyfert 2galaxies. These blue excesses tend to be spatially coincident with thehigh-excitation gas, suggesting an origin related to the nuclearactivity. The blue excesses could originate from a number of differentprocesses, including scattered nuclear light or an extended nonstellarcontinuum associated with the ionized gas (e.g., shock waves).
| The Catalog of Southern Ringed Galaxies
The Catalog of Southern Ringed Galaxies (CSRG) is a comprehensivecompilation of diameters, axis ratios, relative bar position angles, andmorphologies of inner and outer rings, pseudorings, and lenses in 3692galaxies south of declination -17 deg. The purpose of the catalog is toevaluate the idea that these ring phenomena are related to orbitalresonances with a bar or oval in galaxy potentials. The catalog is basedon visual inspection of most of the 606 fields of the Science ResearchCouncil (SRC) IIIa-J southern sky survey, with the ESO-B, ESO-R, andPalomar Sky surveys used as auxiliaries when needed for overexposed coreregions. The catalog is most complete for SRC fields 1-303 (mostly southof declination -42 deg). In addition to ringed galaxies, a list of 859mostly nonringed galaxies intended for comparison with other catalogs isprovided. Other findings from the CSRG that are not based on statisticsare the identification of intrinsic bar/ring misalignment; bars whichunderfill inner rings; dimpling of R'1pseudorings; pointy, rectangular, or hexagonal inner or outer ringshapes; a peculiar polar-ring-related system; and other extreme examplesof spiral structure and ring morphology.
| A volume-limited sample of IRAS galaxies to 4000 km/s, 3: CCD photometry from Palomar and Tololo observatories
An all-sky, quasi-volume-limited sample of 251 spiral galaxies within4000 km/s has been extracted from the redshift survey of InfraredAstronomy Satellite (IRAS) galaxies by Strauss (1992). Distance modulifor these objects estimated via the Tully-Fisher (TF) method allow thepeculiar velocity field and the cosmological density parameter to beconstrained within this volume. The TF relation we exploit relatesdeprojected neutral hydrogen line width to near-infrared luminosity.Herein we present I and V band photometry for 159 members of this sampleobtained with charge coupled device (CCD) cameras at Palomar and Tololoobservatories. Image processing and photometric calibration proceduresare described. Twenty seven objects with multiple calibratedobservations suggest that isophotal I band magnitudes are reproduced toequal to or less than 0.05 mag precision at sigmaI = 23.5 magarcsec-2, and that systematic run-to-run offsets are limitedto equal to or less than 0.05 I mag.
| A volume-limited sample of IRAS galaxies to 4000 km/s, 2: Neutral hydrogen observations from the Parkes telescope
We have extracted a volume-limited sample of spiral galaxies within 4000km/s from the Strauss et al. (1992) redshift survey of InfraredAstronomical Satellite (IRAS) galaxies. The purpose of the sample is touse distances obtained from the neutral hydrogen/near-infrared (I-band)Tully-Fisher relation to study deviations from uniform Hubble expansion.This will allow us to estimate the distribution of mass in the localuniverse and to place constraints on the value of the cosmologicaldensity parameter, omega 0. Here we report neutral hydrogen(H I) observations of 61 galaxies from this sample taken at the 64 mParkes telescope, 48 of which resulted in measured linewidth parameters.Empirical estimates of random and systematic errors in H I line widthsat low signal-to-noise ratio are described.
| The extended 12 micron galaxy sample
We have selected an all-sky (absolute value of b greater than or equalto 25 deg) 12 micron flux-limited sample of 893 galaxies from the IRASFaint Source Catalog, Version 2 (FSC-2). We have obtained accurate totalfluxes in the IRAS wavebands by using the ADDSCAN procedure for allobjects with FSC-2 12 micron fluxes greater than 0.15 Jy and increasingflux densities from 12 to 60 microns, and defined the sample by imposinga survey limit of 0.22 Jy on the total 12 micron flux. Its completenessis verified, by means of the classical log N - log S andV/Vmax tests, down to 0.30 Jy, below which we have measuredthe incompleteness down to the survey limit, using the log N - log Splot, for our statistical analysis. We have obtained redshifts (mostlyfrom catalogs) for virtually all (98.4%) the galaxies in the sample.Using existing catalogs of active galaxies, we defined a subsample of118 objects consisting of 53 Seyfert 1s and quasars, 63 Seyfert 2s, andtwo blazars (approximately 13% of the full sample), which is the largestunbiased sample of Seyfert galaxies ever assembled. Since the 12 micronflux has been shown to be about one-fifth of the bolometric flux forSeyfert galaxies and quasars, the subsample of Seyferts (includingquasars and blazars) is complete not only to 0.30 Jy at 12 microns butalso with respect to a bolometric flux limit of approximately 2.0 x10-10 ergs/s/sq cm. The average value of V/Vmaxfor the full sample, corrected for incompleteness at low fluxes, is 0.51+/- 0.04, expected for a complete sample of uniformly distributedgalaxies, while the value for the Seyfert galaxy subsample is 0.46 +/-0.10. We have derived 12 microns and far-infrared luminosity functionsfor the AGNs, as well as for the entire sample. We extracted from oursample a complete subsample of 235 galaxies flux-limited (8.3 Jy) at 60microns. The 60 micron luminosity function computed for this subsampleis in satisfactory agreement with the ones derived from the brightgalaxy sample (BGS) and the deep high-galactic latitude sample, bothselected at 60 microns.
| 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.
| UBVRI aperture photometry of southern Seyfert galaxies and related objects.
Not Available
| A catalogue of Seyfert galaxies.
Not Available
| New southern galaxies with active nuclei
A list of AGN candidates, identified from optical spectra taken as partof an ongoing redshift survey of southern galaxies, is presented. Theidentification, coordinates, morphological type, measured heliocentricradial velocity, and proposed emission type are given for the galaxiesshowing evidence of nonstellar nuclear activity. Using standarddiagnostics, several new Seyferts and low-ionization nuclear-emissionregions (LINERs) are identified among the emission-line galaxiesobserved.
| Southern Galaxy Catalogue.
Not Available
| Redshifts for 228 southern galaxies
In this paper, new redshifts are presented for 228 galaxies locatedsouth of declination -30 deg. The observations were made with aphoton-counting Reticon detector on the Observatorio Nacional (ON)60-in. telescope. The detector is identical to the one used at MountHopkins for the CfA Redshift Survey, and the redshifts were derivedusing the same data-analysis system. A preliminary comparison withpublished 21-cm redshifts indicates that the velocities have azero-point offset of about -4 km/s, with a typical uncertainty of 40km/s. The observations reported here are the initial results of theON-CfA Redshift Survey currently being undertaken in the southernhemisphere.
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