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A Comparison of Hα and Stellar Scale Lengths in Virgo and Field Spirals
The scale lengths of the old stars and ionized gas distributions arecompared for similar samples of Virgo Cluster members and field spiralgalaxies via Hα and broad R-band surface photometry. While theR-band and Hα scale lengths are, on average, comparable for thecombined sample, we find significant differences between the field andcluster samples. While the Hα scale lengths of the field galaxiesare a factor of 1.14+/-0.07 longer, on average, than their R-band scalelengths, the Hα scale lengths of Virgo Cluster members are, onaverage, 20% smaller than their R-band scale lengths. Furthermore, inVirgo, the scale length ratios are correlated with the size of thestar-forming disk: galaxies with smaller overall Hα extents alsoshow steeper radial falloff of star formation activity. At the sametime, we find no strong trends in scale length ratio as a function ofother galaxy properties, including galaxy luminosity, inclination,morphological type, central R-band light concentration, or bar type. Ourresults for Hα emission are similar to other results for dustemission, suggesting that Hα and dust have similar distributions.The environmental dependence of the Hα scale length placesadditional constraints on the evolutionary process(es) that cause gasdepletion and a suppression of the star formation rate in clusters ofgalaxies.
| The AMIGA sample of isolated galaxies. II. Morphological refinement
We present a refinement of the optical morphologies for galaxies in theCatalog of Isolated Galaxies that forms the basis of the AMIGA (Analysisof the interstellar Medium of Isolated GAlaxies) project. Uniformreclassification using the digitized POSS II data benefited from thehigh resolution and dynamic range of that sky survey. Comparison withindependent classifications made for an SDSS overlap sample of more than200 galaxies confirms the reliability of the early vs. late-typediscrimination and the accuracy of spiral subtypes within Δ T =1-2. CCD images taken at the Observatorio de Sierra Nevada were alsoused to solve ambiguities in early versus late-type classifications. Aconsiderable number of galaxies in the catalog (n = 193) are flagged forthe presence of nearby companions or signs of distortion likely due tointeraction. This most isolated sample of galaxies in the local Universeis dominated by two populations: 1) 82% are spirals (Sa-Sd) with thebulk being luminous systems with small bulges (63% between types Sb-Sc)and 2) a significant population of early-type E-S0 galaxies (14%). Mostof the types later than Sd are low luminosity galaxies concentrated inthe local supercluster where isolation is difficult to evaluate. Thelate-type spiral majority of the sample spans a luminosity rangeMB-corr = -18 to -22 mag. Few of the E/S0 population are moreluminous than -21.0 marking the absence of the often-sought superL* merger (e.g. fossil elliptical) population. The rarity ofhigh luminosity systems results in a fainter derived M* forthis population compared to the spiral optical luminosity function(OLF). The E-S0 population is from 0.2 to 0.6 mag fainter depending onhow the sample is defined. This marks the AMIGA sample as unique amongsamples that compare early and late-type OLFs separately. In othersamples, which always involve galaxies in higher density environments,M^*_E/S0 is almost always 0.3-0.5 mag brighter than M^*_S, presumablyreflecting a stronger correlation between M* andenvironmental density for early-type galaxies.
| Classifications of the Host Galaxies of Supernovae, Set III
A homogeneous sample comprising host galaxies of 604 recent supernovae,including 212 objects discovered primarily in 2003 and 2004, has beenclassified on the David Dunlap Observatory system. Most SN 1991bg-likeSNe Ia occur in E and E/Sa galaxies, whereas the majority of SN1991T-like SNe Ia occur in intermediate-type galaxies. This differenceis significant at the 99.9% level. As expected, all types of SNe II arerare in early-type galaxies, whereas normal SNe Ia occur in all Hubbletypes. This difference is significant at the 99.99% level. A smallnumber of SNe II in E galaxies might be due to galaxy classificationerrors or to a small young-population component in these mainly oldobjects. No significant difference is found between the distributionsover the Hubble type of SNe Ibc and SNe II. This confirms that both ofthese types of objects have similar (massive) progenitors. The presentdata show that in order to understand the dependence of supernova typeon host-galaxy population, it is more important to obtain accuratemorphological classifications than it is to increase the size of thedata sample.
| Photometric Typing Analyses of Three Young Supernovae Observed with the Robotic Palomar 60 Inch Telescope
We present photometric typing analyses of three young supernovaeobserved with the robotic 60 inch (1.5 m) telescope at PalomarObservatory (P60). This represents the first time that such phototyping,conducted in a blind fashion, has been attempted on newly discoveredsupernovae. For one of the target supernovae, SN 2004cs, our photometryprovided the first constraint on the supernova type, which we predictedwould be Type Ia. Contrary to expectations, however, our subsequent Keckspectroscopy shows it to be an unusual Type II supernova. For each ofthe other two supernovae (SN 2004dh [Type II] and SN 2004dk [Type Ib]),our phototyping results are consistent with the known event type asdetermined from ground-based spectroscopy. However, the colors of SN2004dk are also consistent with a Type Ic or Type II classification. Wediscuss our approach to the challenges of phototyping-contamination byhost galaxy light and the unknown photometric quality of the data-forcases in which it is desirable to complete the analysis with just onenight of observations. The growing interest in the properties andbehavior of very young supernovae, and the increased discovery rate forsuch events, mean that prompt phototyping analyses can provide usefulinput for observational campaigns. Our results demonstrate the value andfeasibility of such a project for P60, at the same time illustrating itschief inherent shortcoming: an inability to identify new and unusualevents as such without later spectroscopic observations.
| Supernova 2004dk in NGC 6118
IAUC 8379 available at Central Bureau for Astronomical Telegrams.
| Supernova 2004dk in NGC 6118
IAUC 8377 available at Central Bureau for Astronomical Telegrams.
| A New Nonparametric Approach to Galaxy Morphological Classification
We present two new nonparametric methods for quantifying galaxymorphology: the relative distribution of the galaxy pixel flux values(the Gini coefficient or G) and the second-order moment of the brightest20% of the galaxy's flux (M20). We test the robustness of Gand M20 to decreasing signal-to-noise ratio (S/N) and spatialresolution and find that both measures are reliable to within 10% forimages with average S/N per pixel greater than 2 and resolutions betterthan 1000 and 500 pc, respectively. We have measured G andM20, as well as concentration (C), asymmetry (A), andclumpiness (S) in the rest-frame near-ultraviolet/optical wavelengthsfor 148 bright local ``normal'' Hubble-type galaxies (E-Sd) galaxies, 22dwarf irregulars, and 73 0.05
| Ionized gas and stellar kinematics of seventeen nearby spiral galaxies
Ionized gas and stellar kinematics have been measured along the majoraxes of seventeen nearby spiral galaxies of intermediate to latemorphological type. We discuss the properties of each sample galaxy,distinguishing between those characterized by regular or peculiarkinematics. In most of the observed galaxies, ionized gas rotates morerapidly than stars and has a lower velocity dispersion, as is to beexpected if the gas is confined in the disc and supported by rotationwhile the stars are mostly supported by dynamical pressure. In a fewobjects, gas and stars show almost the same rotational velocity and lowvelocity dispersion, suggesting that their motion is dominated byrotation. Incorporating the spiral galaxies studied by Bertola et al.(\cite{Bertola1996}), Corsini et al. (\cite{Corsini1999},\cite{Corsini2003}) and Vega Beltrán et al. (\cite{Vega2001}) wehave compiled a sample of 50 S0/a-Scd galaxies, for which the major-axiskinematics of the ionized gas and stars have been obtained with the samespatial (≈1'') and spectral (≈50 km;s-1) resolution,and measured with the same analysis techniques. This allowed us toaddress the frequency of counter-rotation in spiral galaxies. It turnsout that less than 12% and less than 8% (at the 95% confidence level) ofthe sample galaxies host a counter-rotating gaseous and stellar disc,respectively. The comparison with S0 galaxies suggests that theretrograde acquisition of small amounts of external gas gives rise tocounter-rotating gaseous discs only in gas-poor S0s, while in gas-richspirals the newly acquired gas is swept away by the pre-existing gas.Counter-rotating gaseous and stellar discs in spirals are formed onlyfrom the retrograde acquisition of large amounts of gas exceeding thatof pre-existing gas, and subsequent star formation, respectively.Based on observations carried out at the European Southern Observatory,La Silla (Chile) (ESO 56.A-0684 and 57.A-0569).Tables 3 and 4 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/424/447Full Fig. \ref{fig:kinematics} and Figs. \ref{fig:gascomparison} and\ref{fig:starcomparison} are only available in electronic form athttp://www.edpsciences.org
| Spiral galaxies observed in the near-infrared K band. I. Data analysis and structural parameters
Deep surface photometry in the K band was obtained for 54 normal spiralgalaxies, with the aim of quantifying the percentage of faint bars andstudying the morphology of spiral arms. The sample was chosen to cover awider range of morphological types while inclination angles anddistances were limited to allow a detailed investigation of the internalstructure of their disks and future observations and studies of the diskkinematics. An additional constraint for a well defined subsample wasthat no bar structure was seen on images in the visual bands. Accuratesky projection parameters were determined from the K maps comparingseveral different methods. The surface brightness distribution wasdecomposed into axisymmetric components while bars and spiral structureswere analyzed using Fourier techniques.Bulges were best represented by a Sérsic r1/n law withan index in the typical range of 1-2. The central surface brightness ofthe exponential disk and bulge-to-disk ratio only showed weakcorrelation with Hubble type. Indications of a central point source werefound in many of the galaxies. An additional central, steep, exponentialdisk improved the fit for more than 80% of the galaxies suggesting thatmany of the bulges are oblate.Bars down to the detection level at a relative amplitude of 3% weredetected in 26 of 30 galaxies in a subsample classified as ordinary SAspirals. This would correspond to only 5% of all spiral galaxies beingnon-barred at this level. In several cases, bars are significantlyoffset compared to the starting points of the main spiral pattern whichindicates that bar and spiral have different pattern speeds. A smallfraction (10%) of the sample has complex central structuresconsisting of several sets of bars, arcs or spirals.A majority of the galaxies (60%) displays a two-armed, grand-designspiral pattern in their inner parts which often breaks up into multiplearms in their outer regions. Phase shifts between the inner and outerpatterns suggest in some cases that they belong to different spiralmodes. The pitch angles of the main two-armed symmetric spiral patternin the galaxies have a typical range of 5-30 °. The sample shows alack of strong, tight spirals which could indicate that such patternsare damped by non-linear, dynamical effects due to their high radialforce perturbations.Based on observations collected at the European Southern Observatory, LaSilla, Chile; programs: ESO 63.N-0343, 65.N-0287, 66.N-0257.Table 2 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/423/849Appendix A is only available in electronic form athttp://www.edpsciences.org
| Deprojecting spiral galaxies using Fourier analysis. Application to the Frei sample
We present two methods that can be used to deproject spirals, based onFourier analysis of their images, and discuss their potential andrestrictions. Our methods perform particularly well for galaxies moreinclined than 50° or for non-barred galaxies moreinclined than 35°. They are fast and straightforward touse, and thus ideal for large samples of galaxies. Moreover, they arevery robust for low resolutions and thus are appropriate for samples ofcosmological interest. The relevant software is available from us uponrequest. We use these methods to determine the values of the positionand inclination angles for a sample of 79 spiral galaxies contained inthe Frei et al. (\cite{frei96}) sample. We compare our results with thevalues found in the literature, based on other methods. We findstatistically very good agreementTable 7 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/415/849
| The Relationship between Stellar Light Distributions of Galaxies and Their Formation Histories
A major problem in extragalactic astronomy is the inability todistinguish in a robust, physical, and model-independent way how galaxypopulations are physically related to each other and to their formationhistories. A similar, but distinct, and also long-standing question iswhether the structural appearances of galaxies, as seen through theirstellar light distributions, contain enough physical information tooffer this classification. We argue through the use of 240 images ofnearby galaxies that three model-independent parameters measured on asingle galaxy image reveal its major ongoing and past formation modesand can be used as a robust classification system. These parametersquantitatively measure: the concentration (C), asymmetry (A), andclumpiness (S) of a galaxy's stellar light distribution. When combinedinto a three-dimensional ``CAS'' volume all major classes of galaxies invarious phases of evolution are cleanly distinguished. We argue thatthese three parameters correlate with important modes of galaxyevolution: star formation and major merging activity. This is arguedthrough the strong correlation of Hα equivalent width andbroadband colors with the clumpiness parameter S, the uniquely largeasymmetries of 66 galaxies undergoing mergers, and the correlation ofbulge to total light ratios, and stellar masses, with the concentrationindex. As an obvious goal is to use this system at high redshifts totrace evolution, we demonstrate that these parameters can be measured,within a reasonable and quantifiable uncertainty with available data outto z~3 using the Hubble Space Telescope GOODS ACS and Hubble Deep Fieldimages.
| Revised positions for CIG galaxies
We present revised positions for the 1051 galaxies belonging to theKarachentseva Catalog of Isolated Galaxies (CIG). New positions werecalculated by applying SExtractor to the Digitized Sky Survey CIG fieldswith a spatial resolution of 1 arcsper 2. We visually checked theresults and for 118 galaxies had to recompute the assigned positions dueto complex morphologies (e.g. distorted isophotes, undefined nuclei,knotty galaxies) or the presence of bright stars. We found differencesbetween older and newer positions of up to 38 arcsec with a mean valueof 2 arcsper 96 relative to SIMBAD and up to 38 arcsec and 2 arcsper 42respectively relative to UZC. Based on star positions from the APMcatalog we determined that the DSS astrometry of five CIG fields has amean offset in (alpha , delta ) of (-0 arcsper 90, 0 arcsper 93) with adispersion of 0 arcsper 4. These results have been confirmed using the2MASS All-Sky Catalog of Point Sources. The intrinsic errors of ourmethod combined with the astrometric ones are of the order of 0 arcsper5.Full Table 1 is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/411/391
| Galaxy classification using fractal signature
Fractal geometry is becoming increasingly important in the study ofimage characteristics. For recognition of regions and objects in naturalscenes, there is always a need for features that are invariant and theyprovide a good set of descriptive values for the region. There are manyfractal features that can be generated from an image. In this paper,fractal signatures of nearby galaxies are studied with the aim ofclassifying them. The fractal signature over a range of scales proved tobe an efficient feature set with good discriminating power. Classifierswere designed using nearest neighbour method and neural networktechnique. Using the nearest distance approach, classification rate wasfound to be 92%. By the neural network method it has been found toincrease to 95%.
| The H I Line Width/Linear Diameter Relationship as an Independent Test of the Hubble Constant
The relationship between corrected H I line widths and linear diameters(LW/LD) for spiral galaxies is used as an independent check on the valueof the Hubble constant. After calibrating the Tully-Fisher (TF) relationin both the B and I bands, the B-band relation is used for galaxies ofmorphological/luminosity types Sc I, Sc I.2, Sc I.3, Sab, Sb, Sb I-II,and Sb II to derive the LW/LD relation. We find that for this sample thescatter in the LW/LD is smallest with a Hubble constant of 90-95 kms-1 Mpc-1. Lower values of the Hubble constantproduce a separation in the LW/LD relation that is a function ofmorphological type. Since a Hubble constant of 90-95 is significantlylarger than the final Key Project value of 72 km s-1Mpc-1, a comparison of TF, surface brightness fluctuation(SBF), and fundamental plane (FP) is made. This comparison indicatesthat the Key Project TF distances to 21 clusters may be too large. For asample of 11 clusters, the Key Project TF distances provide anunweighted mean Hubble constant of 77 km s-1Mpc-1, while a combination of the FP, SBF, and our TFdistances for the same 11 clusters gives H0=91 kms-1 Mpc-1. A more subtle result in our data is amorphological dichotomy in the Hubble constant. The data suggest that ScI galaxies follow a Hubble constant of 90-95 while Sb galaxies follow aHubble constant closer to 75 km s-1 Mpc-1.Possible explanations for this result are considered, but it is shownthat this Sb/Sc I Hubble flow discrepancy is also present in the VirgoCluster and is consistent with previous investigations that indicatethat some galaxies carry a component of age-related intrinsic redshift.
| Bar Galaxies and Their Environments
The prints of the Palomar Sky Survey, luminosity classifications, andradial velocities were used to assign all northern Shapley-Ames galaxiesto either (1) field, (2) group, or (3) cluster environments. Thisinformation for 930 galaxies shows no evidence for a dependence of barfrequency on galaxy environment. This suggests that the formation of abar in a disk galaxy is mainly determined by the properties of theparent galaxy, rather than by the characteristics of its environment.
| Analysis of the distribution of HII regions in external galaxies. IV. The new galaxy sample. Position and inclination angles
We have compiled a new sample of galaxies with published catalogs of HIIregion coordinates. This sample, together with the former catalog ofGarcía-Gómez & Athanassoula (\cite{gga1}), will formthe basis for subsequent studies of the spiral structure in discgalaxies. In this paper we address the problem of the deprojection ofthe galaxy images. For this purpose we use two deprojection methodsbased on the HII region distribution and compare the results with thevalues found in the literature using other deprojection methods. Takinginto account the results of all the methods, we propose optimum valuesfor the position and inclination angles of all the galaxies in oursample. Tables 2 and 3 are only available in electronic form athttp://www.edpsciences.org
| Galaxies with Rows
The results of a search for galaxies with straight structural elements,usually spiral-arm rows (“rows” in the terminology ofVorontsov-Vel'yaminov), are reported. The list of galaxies that possess(or probably possess) such rows includes about 200 objects, of whichabout 70% are brighter than 14m. On the whole, galaxies with rows makeup 6 8% of all spiral galaxies with well-developed spiral patterns. Mostgalaxies with rows are gas-rich Sbc-Scd spirals. The fraction ofinteracting galaxies among them is appreciably higher than amonggalaxies without rows. Earlier conclusions that, as a rule, the lengthsof rows are similar to their galactocentric distances and that theangles between adjacent rows are concentrated near 120° areconfirmed. It is concluded that the rows must be transient hydrodynamicstructures that develop in normal galaxies.
| The Evolution of the Galactic Morphological Types in Clusters
The morphological types of galaxies in nine clusters in the redshiftrange 0.1<~z<~0.25 are derived from very good seeing images takenat the NOT and the La Silla-Danish telescopes, with all galaxies atMV<-20 and within the central ~1 Mpc2 areabeing classified. With the purpose of investigating the evolution of thefraction of different morphological types with redshift, we compare ourresults with the morphological content of nine distant clusters studiedby the MORPHS group, five clusters observed with HST/WFPC2 at redshiftz=0.2-0.3, and Dressler's large sample of nearby clusters. After havingchecked the reliability of our morphological classification both in anabsolute sense and relative to the MORPHS scheme, we analyze therelative occurrence of elliptical, S0, and spiral galaxies as a functionof the cluster properties and redshift. We find a large intrinsicscatter in the S0/E ratio, mostly related to the cluster morphology. Inparticular, in our cluster sample, clusters with a high concentration ofellipticals display a low S0/E ratio and, vice versa, low concentrationclusters have a high S0/E. At the same time, the trend of themorphological fractions (%E's, %S0's, %Sp's) and of the S0/E and S0/Spratios with redshift clearly points to a morphological evolution: as theredshift decreases, the S0 population tends to grow at the expense ofthe spiral population, whereas the frequency of E's remains almostconstant. We also analyze the morphology-density (MD) relation in ourclusters and find that-similarly to higher redshift clusters-a good MDrelation exists in the high-concentration clusters, while it is absentin the less concentrated clusters. Finally, the comparison of the MDrelation in our clusters with that of the MORPHS sample suggests thatthe transformation of spirals into S0 galaxies becomes more efficientwith decreasing local density.
| The Asymmetry of Galaxies: Physical Morphology for Nearby and High-Redshift Galaxies
We present a detailed study of rotational asymmetry in galaxies for bothmorphological and physical diagnostic purposes. An unambiguous methodfor computing asymmetry is developed, which is robust for both distantand nearby galaxies. By degrading real galaxy images, we test thereliability of this asymmetry measure over a range of observationalconditions, e.g., spatial resolution and signal-to-noise ratio (S/N).Compared to previous methods, this new algorithm avoids the ambiguityassociated with choosing a center by using a minimization method andsuccessfully corrects for variations in S/N. There is, however, a strongrelationship between the rotational asymmetry and physical resolution(distance at fixed spatial resolution): objects become more symmetricwhen less well-resolved. We further investigate asymmetry as a functionof galactic radius and rotation. We find the asymmetry index has astrong radial dependence that differs vastly between Hubble types. As aresult, a meaningful asymmetry index must be specified within awell-defined radius representative of the physical galaxy scale. Weenumerate several viable alternatives, which exclude the use ofisophotes. Asymmetry as a function of angle (Aφ) is alsoa useful indicator of ellipticity and higher order azimuthal structure.In general, we show that the power of asymmetry as a morphologicalparameter lies in the strong correlation with B-V color for galaxiesundergoing normal star formation spanning all Hubble types fromellipticals to irregular galaxies. The few interacting galaxies in ourstudy do not fall on this asymmetry-color ``fiducial sequence,'' asthese galaxies are too asymmetric for their color. We suggest this factcan be used to distinguish between ``normal'' galaxies and galaxiesundergoing an interaction or merger.
| Structural and Photometric Classification of Galaxies. I. Calibration Based on a Nearby Galaxy Sample
In this paper we define an observationally robust, multiparameter spacefor the classification of nearby and distant galaxies. The parametersinclude luminosity, color, and the image-structure parameters: size,image concentration, asymmetry, and surface brightness. Based on aninitial calibration of this parameter space using the ``normal'' Hubbletypes surveyed in 1996 by Frei et al., we find that only a subset of theparameters provide useful classification boundaries for this sample.Interestingly, this subset does not include distance-dependent scaleparameters such as size or luminosity. The essential ingredient is thecombination of a spectral index (e.g., color) with parameters of imagestructure and scale: concentration, asymmetry, and surface brightness.We refer to the image structure parameters (concentration and asymmetry)as indices of ``form.'' We define a preliminary classification based onspectral index, form, and surface brightness (a scale) that successfullyseparates normal galaxies into three classes. We intentionally identifythese classes with the familiar labels of early, intermediate, and late.This classification, or others based on the above four parameters, canbe used reliably to define comparable samples over a broad range inredshift. The size and luminosity distribution of such samples will notbe biased by this selection process except through astrophysicalcorrelations between spectral index, form, and surface brightness.
| The Star Formation History of the Starburst Region NGC 2363 and its Surroundings
We present Hubble Space Telescope optical images and UV spectra, as wellas ground-based near-infrared images of the high surface-brightnessgiant H II region NGC 2363 (NGC 2366-I) and its surroundings. Themassive star content of the southern end of the dwarf irregular galaxyNGC 2366 is investigated, with an emphasis on Wolf-Rayet and redsupergiant stars, and we attempt the reconstruction of the time sequenceof the most recent episode of massive star formation at the southwesterntip of the galaxy. The ages of the clusters are, respectively, 10 Myrfor NGC 2366-II, 2.5-5 Myr for NGC 2363-B, and less than 1 Myr for NGC2363-A. In particular, we show that the most massive supercluster A ofNGC 2363 is still embedded in dust; from the photoevaporative erosion or``cleaning'' timescale of the associated cloud, we infer its age to be~106 yr or less. We conclude that the star-forming complexNGC 2366-I and 2366-II is a good example of a multiple stage starburstwith a characteristic age decreasing from 10 Myr to less than 1 Myr overa linear scale of 400 pc. The age sequence of the stars and the gaskinematics suggest that these powerful star formation episodes are beingtriggered by a small passing-by satellite. Based on observations withthe NASA/ESA Hubble Space Telescope, obtained at the Space TelescopeScience Institute, which is operated by AURA, Inc., under NASA contractNAS 5-26555.
| 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
| The QDOT all-sky IRAS galaxy redshift survey
We describe the construction of the QDOT survey, which is publiclyavailable from an anonymous FTP account. The catalogue consists ofinfrared properties and redshifts of an all-sky sample of 2387 IRASgalaxies brighter than the IRAS PSC 60-μm completeness limit(S_60>0.6Jy), sparsely sampled at a rate of one-in-six. At |b|>10deg, after removing a small number of Galactic sources, the redshiftcompleteness is better than 98per cent (2086/2127). New redshifts for1401 IRAS sources were obtained to complete the catalogue; themeasurement and reduction of these are described, and the new redshiftstabulated here. We also tabulate all sources at |b|>10 deg with noredshift so far, and sources with conflicting alternative redshiftseither from our own work, or from published velocities. A list of 95ultraluminous galaxies (i.e. with L_60μm>10^12 L_solar) is alsoprovided. Of these, ~20per cent are AGN of some kind; the broad-lineobjects typically show strong Feii emission. Since the publication ofthe first QDOT papers, there have been several hundred velocity changes:some velocities are new, some QDOT velocities have been replaced by moreaccurate values, and some errors have been corrected. We also present anew analysis of the accuracy and linearity of IRAS 60-μm fluxes. Wefind that the flux uncertainties are well described by a combination of0.05-Jy fixed size uncertainty and 8per cent fractional uncertainty.This is not enough to cause the large Malmquist-type errors in the rateof evolution postulated by Fisher et al. We do, however, find marginalevidence for non-linearity in the PSC 60-μm flux scale, in the sensethat faint sources may have fluxes overestimated by about 5per centcompared with bright sources. We update some of the previous scientificanalyses to assess the changes. The main new results are as follows. (1)The luminosity function is very well determined overall but is uncertainby a factor of several at the very highest luminosities(L_60μm>5x10^12L_solar), as this is where the remainingunidentified objects are almost certainly concentrated. (2) Thebest-fitting rate of evolution is somewhat lower than our previousestimate; expressed as pure density evolution with density varying as(1+z)^p, we find p=5.6+/-2.3. Making a rough correction for the possible(but very uncertain) non-linearity of fluxes, we find p=4.5+/-2.3. (3)The dipole amplitude decreases a little, and the implied value of thedensity parameter, assuming that IRAS galaxies trace the mass, isΩ=0.9(+0.45, -0.25). (4) Finally, the estimate of density varianceon large scales changes negligibly, still indicating a significantdiscrepancy from the predictions of simple cold dark matter cosmogonies.
| Arcsecond Positions of UGC Galaxies
We present accurate B1950 and J2000 positions for all confirmed galaxiesin the Uppsala General Catalog (UGC). The positions were measuredvisually from Digitized Sky Survey images with rms uncertaintiesσ<=[(1.2")2+(θ/100)2]1/2,where θ is the major-axis diameter. We compared each galaxymeasured with the original UGC description to ensure high reliability.The full position list is available in the electronic version only.
| Galaxy Structural Parameters: Star Formation Rate and Evolution with Redshift
The evolution of the structure of galaxies as a function of redshift isinvestigated using two parameters: the metric radius of the galaxy(R_eta) and the power at high spatial frequencies in the disk of thegalaxy (chi). A direct comparison is made between nearby (z~0) anddistant (0.2<~z<~1) galaxies by following a fixed range in restframe wavelengths. The data of the nearby galaxies comprise 136broadband images at ~4500 Å observed with the 0.9 m telescope atKitt Peak National Observatory (23 galaxies) and selected from thecatalog of digital images of Frei et al. (113 galaxies). Thehigh-redshift sample comprises 94 galaxies selected from the Hubble DeepField (HDF) observations with the Hubble Space Telescope using the WideField Planetary Camera 2 in four broad bands that range between ~3000and ~9000 Å (Williams et al.). The radius is measured from theintensity profile of the galaxy using the formulation of Petrosian, andit is argued to be a metric radius that should not depend very stronglyon the angular resolution and limiting surface brightness level of theimaging data. It is found that the metric radii of nearby and distantgalaxies are comparable to each other. The median value of the radius ofthe local sample is ~5+/-1 kpc, and the median radius ofthe HDF sample is ~6+/-2 kpc for q_0=0.5, H_0=65 km s^-1Mpc^-1 however, for q_0=0.1, ~7 kpc and for q_0=1,~5 kpc. In the HDF, galaxies with redshifts larger thanz>0.6 have flatter R_eta distributions than galaxies with redshiftssmaller than z<=0.6. However, the median R_eta values of high- andlow-redshift galaxies are consistent with each other. This result isconsistent with the simulations of galaxy images at redshifts z=0.35,z=0.5, and z=0.9, which show that the metric sizes can be recoveredwithin +/-2 kpc. The flocculency or power at high spatial frequencies isquantified using a simple method that is based on surface photometry inone band and that depends on the size of the star-forming regions and onthe intensity profile of the galaxy. In nearby galaxies, the flocculencyis found to trace the star formation rate as chi is correlated withoptical colors (B-V) and the strength of the hydrogen recombinationlines (Hα). In the HDF, galaxies at redshifts smaller than z~1 andwith fluxes brighter than B=25 have values of chi similar to what ismeasured in nearby galaxies and to what is expected from simulations ofdistant galaxy images. Among the HDF galaxies, I find that at most 4%can be identified as dwarf galaxies with rates of star formation similarto NGC 4449 and NGC 1569. Most HDF galaxies are giants with starformation rates similar to those in nearby giant galaxies. In summary,in this study I have introduced a method to measure the metric sizes andflocculency of the two-dimensional light distribution of galaxies. As aresult, I find that the high spatial frequency power is related to thestar formation rate. Further, I find that the sizes and power at highspatial frequencies of HDF galaxies remain largely unchanged between thepresent epoch and redshifts lower than z~1.
| Bulge-Disk Decomposition of 659 Spiral and Lenticular Galaxy Brightness Profiles
We present one of the largest homogeneous sets of spiral and lenticulargalaxy brightness profile decompositions completed to date. The 659galaxies in our sample have been fitted with a de Vaucouleurs law forthe bulge component and an inner-truncated exponential for the diskcomponent. Of the 659 galaxies in the sample, 620 were successfullyfitted with the chosen fitting functions. The fits are generally welldefined, with more than 90% having rms deviations from the observedprofile of less than 0.35 mag. We find no correlations of fittingquality, as measured by these rms residuals, with either morphologicaltype or inclination. Similarly, the estimated errors of the fittedcoefficients show no significant trends with type or inclination. Thesedecompositions form a useful basis for the study of the lightdistributions of spiral and lenticular galaxies. The object base issufficiently large that well-defined samples of galaxies can be selectedfrom it.
| Asymmetry in high-precision global H I profiles of isolated spiral galaxies
New high-SNR 21 cm H I line profiles have been obtained for 104 galaxieswith the Green Bank 43 m telescope. The primary sample is composed ofisolated spirals with no known optical companions within a 1 radius anda median ratio of optical diameter to beamwidth of 0.17. An effort wasmade to ensure linearity of baseline fitting and precise flux densitycalibration to better than 5 percent. Two quantitative measures ofasymmetry are applied to assess the occurrence of lopsidedness in theglobal H I profiles. In agreement with previous estimates, half thegalaxies show significant H I profile asymmetries. The lopsidednesscannot be explained by pointing offsets but, rather, must result fromnoncircular motions, confusion with unidentified companions within thetelescope beam, or true distortions in the H I distribution.
| Scale height determination of 10 spiral galaxies (NGC 1019 and others).
Not Available
| Catalogue of HI maps of galaxies. I.
A catalogue is presented of galaxies having large-scale observations inthe HI line. This catalogue collects from the literature the informationthat characterizes the observations in the 21-cm line and the way thatthese data were presented by means of maps, graphics and tables, forshowing the distribution and kinematics of the gas. It containsfurthermore a measure of the HI extension that is detected at the levelof the maximum sensitivity reached in the observations. This catalogueis intended as a guide for references on the HI maps published in theliterature from 1953 to 1995 and is the basis for the analysis of thedata presented in Paper II. The catalogue is only available inelectronic form at the CDS via anonymous ftp 130.79.128.5 orhttp://cdsweb.u-strasbg.fr/Abstract.html
| Total magnitude, radius, colour indices, colour gradients and photometric type of galaxies
We present a catalogue of aperture photometry of galaxies, in UBVRI,assembled from three different origins: (i) an update of the catalogueof Buta et al. (1995) (ii) published photometric profiles and (iii)aperture photometry performed on CCD images. We explored different setsof growth curves to fit these data: (i) The Sersic law, (ii) The net ofgrowth curves used for the preparation of the RC3 and (iii) A linearinterpolation between the de Vaucouleurs (r(1/4) ) and exponential laws.Finally we adopted the latter solution. Fitting these growth curves, wederive (1) the total magnitude, (2) the effective radius, (3) the colourindices and (4) gradients and (5) the photometric type of 5169 galaxies.The photometric type is defined to statistically match the revisedmorphologic type and parametrizes the shape of the growth curve. It iscoded from -9, for very concentrated galaxies, to +10, for diffusegalaxies. Based in part on observations collected at the Haute-ProvenceObservatory.
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