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Properties of tidally-triggered vertical disk perturbations
We present a detailed analysis of the properties of warps andtidally-triggered perturbations perpendicular to the plane of 47interacting/merging edge-on spiral galaxies. The derived parameters arecompared with those obtained for a sample of 61 non-interacting edge-onspirals. The entire optical (R-band) sample used for this study waspresented in two previous papers. We find that the scale height of disksin the interacting/merging sample is characterized by perturbations onboth large ( =~ disk cut-off radius) and short ( =~ z0)scales, with amplitudes of the order of 280 pc and 130 pc on average,respectively. The size of these large (short) -scale instabilitiescorresponds to 14% (6%) of the mean disk scale height. This is a factorof 2 (1.5) larger than the value found for non-interacting galaxies. Ahallmark of nearly all tidally distorted disks is a scale height thatincreases systematically with radial distance. The frequent occurrenceand the significantly larger size of these gradients indicate that diskasymmetries on large scales are a common and persistent phenomenon,while local disturbances and bending instabilities decline on shortertimescales. Nearly all (93%) of the interacting/merging and 45% of thenon-interacting galaxies studied are noticeably warped. Warps ofinteracting/merging galaxies are ~ 2.5 times larger on average thanthose observed in the non-interacting sample, with sizes of the order of340 pc and 140 pc, respectively. This indicates that tidal distortionsdo considerably contribute to the formation and size of warps. However,they cannot entirely explain the frequent occurrence of warped disks.Based on observations obtained at the European Southern Observatory(ESO, La Silla, Chile), Calar Alto Observatory operated by the MPIA(DSAZ, Spain), Lowell Observatory (Flagstaff,AZ, USA), and Hoher ListObservatory (Germany).
| 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.
| Box- and peanut-shaped bulges. I. Statistics
We present a classification for bulges of a complete sample of ~ 1350edge-on disk galaxies derived from the RC3 (Third Reference Catalogue ofBright Galaxies, de Vaucouleurs et al. \cite{rc3}). A visualclassification of the bulges using the Digitized Sky Survey (DSS) inthree types of b/p bulges or as an elliptical type is presented andsupported by CCD images. NIR observations reveal that dust extinctiondoes almost not influence the shape of bulges. There is no substantialdifference between the shape of bulges in the optical and in the NIR.Our analysis reveals that 45% of all bulges are box- and peanut-shaped(b/p). The frequency of b/p bulges for all morphological types from S0to Sd is > 40%. In particular, this is for the first time that such alarge frequency of b/p bulges is reported for galaxies as late as Sd.The fraction of the observed b/p bulges is large enough to explain theb/p bulges by bars. Partly based on observations collected at ESO/LaSilla (Chile), DSAZ/Calar Alto (Spain), and Lowell Observatory/Flagstaff(AZ/U.S.A.). Tables 6 and 7 are only available in electronic form at CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Three-dimensional modelling of edge-on disk galaxies
We present detailed three-dimensional modelling of the stellarluminosity distribution for the disks of 31 relatively nearby (<= 110Mpc) edge-on spiral galaxies. In contrast to most of the standardmethods available in the literature we take into account the fullthree-dimensional information of the disk. We minimize the differencebetween the observed 2D-image and an image of our 3D-disk modelintegrated along the line of sight. Thereby we specify the inclination,the fitting function for the z-distribution of the disk, and the bestvalues for the structural parameters such as scalelength, scaleheight,central surface brightness, and a disk cut-off radius. From a comparisonof two independently developed methods we conclude, that thediscrepancies e.g. for the scaleheights and scalelengths are of theorder of ~10%. These differences are not due to the individual methoditself, but rather to the selected fitting region, which masks the bulgecomponent, the dust lane, or present foreground stars. Other seriouslimitations are small but appreciable intrinsic deviations of real diskscompared to the simple input model. In this paper we describe themethods and present contour plots as well as radial profiles for allgalaxies without previously published surface photometry. Resultingparameters are given for the complete sample. Based on observationscollected at the European Southern Observatory, Chile and LowellObservatory, Flagstaff (AZ), U.S.A.
| The influence of interactions and minor mergers on the structure of galactic disks I. Observations and disk models
This paper is the first part in our series on the influence of tidalinteractions and minor mergers on the radial and vertical disk structureof spiral galaxies. We report on the sample selection, our observations,and data reduction. Surface photometry of the optical and near infrareddata of a sample of 110 highly-inclined/edge-on disk galaxies arepresented. This sample consists of two subsamples of 61 non-interactinggalaxies (control sample) and of 49 interacting galaxies/minor mergingcandidates. Additionally, 41 of these galaxies were observed in the nearinfrared. We show that the distribution of morphological types of bothsubsamples is almost indistinguishable, covering the range between 0<= T <= 9. An improved, 3-dimensional disk modelling- and fittingprocedure is described in order to analyze and to compare the diskstructure of our sample galaxies by using characteristic parameters. Wefind that the vertical brightness profiles of galactic disks respondvery sensitive even to small deviations from the perfect edge-onorientation. Hence, projection effects of slightly inclined disks maycause substantial changes in the value of the disk scale height and musttherefore be considered in the subsequent study. Based on observationsobtained at the European Southern Observatory (ESO, La Silla, Chile),Calar Alto Observatory operated by the MPIA (DSAZ, Spain), LowellObservatory (Flagstaff/AZ, USA), and Hoher List Observatory (Germany).
| The influence of interactions and minor mergers on the structure of galactic disks. II. Results and interpretations
We present the second part of a detailed statistical study focussed onthe effects of tidal interactions and minor mergers on the radial andvertical disk structure of spiral galaxies. In the first part wereported on the sample selection, observations, and applied disk models.In this paper the results are presented, based on disk parametersderived from a sample of 110 highly-inclined/edge-on galaxies. Thissample consists of two subsamples of 49 interacting/merging and 61non-interacting galaxies. Additionally, 41 of these galaxies wereobserved in the NIR. We find significant changes of the disk structurein vertical direction, resulting in ~ 1.5 times larger scale heights andthus vertical velocity dispersions. The radial disk structure,characterized by the cut-off radius and the scale length, shows nostatistically significant changes. Thus, the ratio of radial to verticalscale parameters, h/z0, is ~ 1.7 times smaller for the sampleof interacting/merging galaxies. The total lack of typical flat diskratios h/z0 > 7 in the latter sample implies that verticaldisk heating is most efficient for (extremely) thin disks. Statisticallynearly all galactic disks in the sample (93%) possess non-isothermalvertical luminosity profiles like the sech (60%) and exp (33%)distribution, independent of the sample and passband investigated. Thisindicates that, in spite of tidal perturbations and disk thickening, theinitial vertical distribution of disk stars is not destroyed byinteractions or minor mergers. Based on observations obtained at theEuropean Southern Observatory (ESO, La Silla, Chile), Calar AltoObservatory operated by the MPIA (DSAZ, Spain), Lowell Observatory(Flagstaff/AZ, USA), and Hoher List Observatory (Germany).
| Very Wide Galaxy Pairs of the Northern and Southern Sky
We present highly accurate observations of the 21 cm line of hydrogen ingalaxies made at the Arecibo and Parkes Observatories. The galaxiesobserved have been identified, through rigorous selection criteriaapplied to the CfA and SSRS catalogs, as being members of pairs withprojected separations of up to 1.5 Mpc (H0 = 75 km s-1 Mpc-1). Theseobservations form the completion of the Chengalur-Nordgren galaxy pairsample with data previously published by Chengalur, Nordgren andcolleagues. The new selection criteria used in this paper are anextension to larger projected separations of the criteria usedpreviously. Forty-nine new galaxies are observed, while H I is detectedin 41 of them. With the addition of these galaxies, the completed samplehas highly accurate H I velocities for a total of 219 galaxies.
| 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.
| 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
| 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
| The Stromlo-APM Redshift Survey. IV. The Redshift Catalog
The Stromlo-APM Redshift Survey consists of 1797 galaxies with b_J_ <17.15 selected randomly at a rate of 1 in 20 from automated platemeasurement (APM) scans. The survey covers a solid angle of 1.3 sr (4300deg^2^) in the south Galactic cap. Redshifts have been measured for 1790(99.6%) of the galaxies. The median galaxy recession velocity is 15,300km s^-1^, and so the volume probed is V ~ 1.38 x 10^6^ h^-3^ Mpc^3^. Inthis paper we describe the construction of the redshift catalog andpresent the survey data.
| 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.
| 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.
| Parameters of stellar disks from CCD surface photometry of edge-on galaxies
CCD surface photometry in Thuan and Gunn g and r filters is used tostudy the structure of stellar disks in 27 edge-on galaxies. Parametersfor models of the light distribution such as the scale height z_0_, theradial scale length h, the cut-off radius R_max_, and the centralsurface brightness μ_0_ are determined. The observed disks generallyshow a radial cut-off at a surface brightness level of ~23mag/arcsec^2^, well above the signal-to-noise limit. Several galaxies inour sample have a ratio R_max_/h<3.0, smaller than typical valuesfound in previous studies. The light distribution perpendicular to theplane is, even at visual wavelength, better described by an exponentialor a sech function in z than by the sech^2^ function of an isothermaldisk model. The central face-on corrected surface brightness μ_0_ ofthe disks presented here are lower than values of comparable face-onsamples.
| 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.
| Observations of edge-on galaxies at 843 MHz
With the intention of investigating cosmic ray distribution andpropagation in the haloes of normal spiral galaxies, 30 edge-on galaxieswere observed at 843 MHz with the Molonglo Observatory SynthesisTelescope. Some results of this study are presented here. Of the 24galaxies detected, sixteen were partially resolved. Fourteen of thecorresponding maps are presented as overlays on optical images. Theseven galaxies with unresolved or marginally resolved emission were allof morphological type SO or Sa. Three galaxies, NGC 2613, IC 5052, andNGC 7184, each appear to possess two weak continuum maxima and should bereobserved so that more sensitive maps can be made.
| Characterising 'box/peanut' galactic bulge morphology
Principal component analyses have been conducted on a large sample ofedge-on galaxies displaying 'box' or 'peanut' shaped bulge distortionsin order to identify the characteristic photometric properties of themorphology. The identified parameter space is strictly two-dimensional,indicating that no single parameter exists by which box/peanutmorphology could be fully characterized. The most significant parametersare measures of bulge dimension, and the bulge-to-total luminosityratio. It is shown that weak boxes and extreme peanuts are merelyextrema in a homogeneous family of isophotal distortions. The resultsalso suggest that the disk component is not an important constraint onthe formation and/or subsequent evolution of box/peanut bulgedistortions.
| A southern redshift survey. I - Accurate redshifts for 500 galaxies observed at SAAO
Radial velocities are presented for about 500 galaxies observed with anintensified Reticon photon-counting detector attached to the 1.9 mtelescope at the Sutherland field station of SAAO. The velocities weredetermined by cross correlation with standard velocity templates, fromthe measured wavelengths of emission lines, or from both techniques,with spectra covering the wavelength range from 3700 to 5400 A. Thefinal velocities appear to have the same zero point as H I radiovelocities, and have standard deviations of the order of 35 km/s, thoughcross-correlation velocities on their own may have significantly largererrors.
| The ON-CfA redshift survey of the southern hemisphere
A redshift survey of a diameter-limited sample of southern galaxies hasbeen performed by the Observatorio Nacional in collaboration with theHarvard-Smithsonian Center for Astrophysics. Redshift data are presentedfor 442 galaxies. A relatively small mean difference of -5.2 km/s wasfound between the present redshifts and previous radio data.
| A search for box- or peanut-shaped bulges
A search for disk galaxies with box- or peanut-shaped bulges from theESO/SERC J sky survey south of declination -18 deg has revealed 30 suchgalaxies. Adding to these 11 other galaxies already known to have asimilar morphology yields a bimodal frequency distribution with Hubbletype: there is a strong tendency for box- and peanut-shaped bulges tooccur in S0 and Sab to Sb type galaxies. Furthermore, the disk-to-bulgeluminosity ratios of the S0 galaxies are similar to the spiral galaxiesthat have box- and peanut-shaped bulges, i.e., Sab and Sb Hubble types.Of the total sample of 41 galaxies, 54 percent are possible members ofclusters and 63 percent have peanut-shaped bulges, compared tobox-shaped bulges. Galaxy counts show that about 1.2 percent of all diskgalaxies have box- or peanut-shaped bulges.
| The minor axis profiles of galaxies with box- and peanut-shaped bulges
CCD surface photometry of the minor axis brightness profiles of fiveedge-on galaxies with box- or peanut-shaped bulges is presented. Theprofile of NGC 5746 consists of two separate components and looks verymuch similar to the unusual and until now unique profile of NGC 4565.The distinct difference between the minor axis profiles of NGC 4565 andNGC 5746 and the other 4 profiles presented here shows that galaxieswith such bulges are not a homogeneous group.
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