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How large are the bars in barred galaxies?
I present a study of the sizes (semimajor axes) of bars in discgalaxies, combining a detailed R-band study of 65 S0-Sb galaxies withthe B-band measurements of 70 Sb-Sd galaxies from Martin (1995). As hasbeen noted before with smaller samples, bars in early-type (S0-Sb)galaxies are clearly larger than bars in late-type (Sc-Sd) galaxies;this is true both for relative sizes (bar length as fraction ofisophotal radius R25 or exponential disc scalelength h) andabsolute sizes (kpc). S0-Sab bars extend to ~1-10 kpc (mean ~ 3.3 kpc),~0.2-0.8R25 (mean ~ 0.38R25) and ~0.5-2.5h (mean ~1.4h). Late-type bars extend to only ~0.5-3.5 kpc,~0.05-0.35R25 and 0.2-1.5h their mean sizes are ~1.5 kpc, ~0.14R25 and ~0.6h. Sb galaxies resemble earlier-type galaxiesin terms of bar size relative to h; their smallerR25-relative sizes may be a side effect of higher starformation, which increases R25 but not h. Sbc galaxies form atransition between the early- and late-type regimes. For S0-Sbcgalaxies, bar size correlates well with disc size (both R25and h); these correlations are stronger than the known correlation withMB. All correlations appear to be weaker or absent forlate-type galaxies; in particular, there seems to be no correlationbetween bar size and either h or MB for Sc-Sd galaxies.Because bar size scales with disc size and galaxy magnitude for mostHubble types, studies of bar evolution with redshift should selectsamples with similar distributions of disc size or magnitude(extrapolated to present-day values); otherwise, bar frequencies andsizes could be mis-estimated. Because early-type galaxies tend to havelarger bars, resolution-limited studies will preferentially find bars inearly-type galaxies (assuming no significant differential evolution inbar sizes). I show that the bars detected in Hubble Space Telescope(HST) near-infrared(IR) images at z~ 1 by Sheth et al. have absolutesizes consistent with those in bright, nearby S0-Sb galaxies. I alsocompare the sizes of real bars with those produced in simulations anddiscuss some possible implications for scenarios of secular evolutionalong the Hubble sequence. Simulations often produce bars as large as(or larger than) those seen in S0-Sb galaxies, but rarely any as smallas those in Sc-Sd galaxies.
| Ultraluminous X-Ray Sources in Nearby Galaxies from ROSAT High Resolution Imager Observations I. Data Analysis
X-ray observations have revealed in other galaxies a class ofextranuclear X-ray point sources with X-ray luminosities of1039-1041 ergs s-1, exceeding theEddington luminosity for stellar mass X-ray binaries. Theseultraluminous X-ray sources (ULXs) may be powered by intermediate-massblack holes of a few thousand Msolar or stellar mass blackholes with special radiation processes. In this paper, we present asurvey of ULXs in 313 nearby galaxies withD25>1' within 40 Mpc with 467 ROSAT HighResolution Imager (HRI) archival observations. The HRI observations arereduced with uniform procedures, refined by simulations that help definethe point source detection algorithm employed in this survey. A sampleof 562 extragalactic X-ray point sources withLX=1038-1043 ergs s-1 isextracted from 173 survey galaxies, including 106 ULX candidates withinthe D25 isophotes of 63 galaxies and 110 ULX candidatesbetween 1D25 and 2D25 of 64 galaxies, from which aclean sample of 109 ULXs is constructed to minimize the contaminationfrom foreground or background objects. The strong connection betweenULXs and star formation is confirmed based on the striking preference ofULXs to occur in late-type galaxies, especially in star-forming regionssuch as spiral arms. ULXs are variable on timescales over days to yearsand exhibit a variety of long term variability patterns. Theidentifications of ULXs in the clean sample show some ULXs identified assupernovae (remnants), H II regions/nebulae, or young massive stars instar-forming regions, and a few other ULXs identified as old globularclusters. In a subsequent paper, the statistic properties of the surveywill be studied to calculate the occurrence frequencies and luminosityfunctions for ULXs in different types of galaxies to shed light on thenature of these enigmatic sources.
| A sample of X-ray emitting normal galaxies from the BMW-HRI Catalogue
We obtained a sample of 143 normal galaxies with X-ray luminosity in therange 1038{-}1043 erg s-1 from thecross-correlation of the ROSAT HRI Brera Multi-scale Wavelet (BMW-HRI)Catalogue with the Lyon-Meudon Extragalactic Database (LEDA). We findthat the average X-ray properties of this sample are in good agreementwith those of other samples of galaxies in the literature. We selected acomplete flux limited serendipitous sample of 32 galaxies from which wederived the log N-log S distribution of normal galaxies in the fluxrange 1.1{-} 110 × 10-14 erg cm-2s-1. The resulting distribution is consistent with theEuclidean -1.5 slope. Comparisons with other samples, such as theExtended Medium Sensitivity Survey, the ROSAT All Sky Survey, theXMM-Newton/2dF survey, and the Chandra Deep Field Survey indicate thatthe log N -log S distribution of normal galaxies is consistent with aEuclidean slope over a flux range of about 6 decades.
| The Relation between Galaxy Activity and the Dynamics of Compact Groups of Galaxies
Using a sample of 91 galaxies distributed over 27 compact groups (CGs)of galaxies, we define an index that allows us to quantify their levelof activity due to an active galactic nucleus (AGN) or star formation.By combining the mean activity index with the mean morphological type ofthe galaxies in a group, we are able to quantify the evolutionary stateof the groups. We find that they span an evolutionary sequence thatcorrelates with the spatial configuration of the galaxies in the CG. Wedistinguish three main configuration types: A, B, and C. Type A CGs showpredominantly low velocity dispersions and are rich in late-type spiralsthat show active star formation or harbor an AGN. Type B groups haveintermediate velocity dispersions and contain a large fraction ofinteracting or merging galaxies. Type C comprises CGs with high velocitydispersions, which are dominated by elliptical galaxies that show noactivity. We suggest that evolution proceeds A==>B==>C. Mappingthe groups with different evolution levels in a diagram of radius versusvelocity dispersion does not reveal the pattern expected based on theconventional fast merger model for CGs, which predicts a direct relationbetween these two parameters. Instead, we observe a trend contrary toexpectation: the evolutionary state of a group increases with velocitydispersion. This trend seems to be related to the masses of thestructures in which CGs are embedded. In general, the evolutionary stateof a group increases with the mass of the structure. This suggestseither that galaxies evolve more rapidly in massive structures or thatthe formation of CGs embedded in massive structures predated theformation of CGs associated with lower mass systems. Our observationsare consistent with the structure formation predicted by the CDM model(or ΛCDM), only if the formation of galaxies is a biased process.
| Inner-truncated Disks in Galaxies
We present an analysis of the disk brightness profiles of 218 spiral andlenticular galaxies. At least 28% of disk galaxies exhibit innertruncations in these profiles. There are no significant trends oftruncation incidence with Hubble type, but the incidence among barredsystems is 49%, more than 4 times that for nonbarred galaxies. However,not all barred systems have inner truncations, and not allinner-truncated systems are currently barred. Truncations represent areal dearth of disk stars in the inner regions and are not an artifactof our selection or fitting procedures nor the result of obscuration bydust. Disk surface brightness profiles in the outer regions are wellrepresented by simple exponentials for both truncated and nontruncateddisks. However, truncated and nontruncated systems have systematicallydifferent slopes and central surface brightness parameters for theirdisk brightness distributions. Truncation radii do not appear tocorrelate well with the sizes or brightnesses of the bulges. Thissuggests that the low angular momentum material apparently missing fromthe inner disk was not simply consumed in forming the bulge population.Disk parameters and the statistics of bar orientations in our sampleindicate that the missing stars of the inner disk have not simply beenredistributed azimuthally into bar structures. The sharpness of thebrightness truncations and their locations with respect to othergalactic structures suggest that resonances associated with diskkinematics, or tidal interactions with the mass of bulge stars, might beresponsible for this phenomenon.
| 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
| Properties of isolated disk galaxies
We present a new sample of northern isolated galaxies, which are definedby the physical criterion that they were not affected by other galaxiesin their evolution during the last few Gyr. To find them we used thelogarithmic ratio, f, between inner and tidal forces acting upon thecandidate galaxy by a possible perturber. The analysis of thedistribution of the f-values for the galaxies in the Coma cluster leadus to adopt the criterion f ≤ -4.5 for isolated galaxies. Thecandidates were chosen from the CfA catalog of galaxies within thevolume defined by cz ≤5000 km s-1, galactic latitudehigher than 40o and declination ≥-2.5o. Theselection of the sample, based on redshift values (when available),magnitudes and sizes of the candidate galaxies and possible perturberspresent in the same field is discussed. The final list of selectedisolated galaxies includes 203 objects from the initial 1706. The listcontains only truly isolated galaxies in the sense defined, but it is byno means complete, since all the galaxies with possible companions underthe f-criterion but with unknown redshift were discarded. We alsoselected a sample of perturbed galaxies comprised of all the diskgalaxies from the initial list with companions (with known redshift)satisfying f ≥ -2 and \Delta(cz) ≤500 km s-1; a totalof 130 objects. The statistical comparison of both samples showssignificant differences in morphology, sizes, masses, luminosities andcolor indices. Confirming previous results, we found that late spiral,Sc-type galaxies are, in particular, more frequent among isolatedgalaxies, whereas Lenticular galaxies are more abundant among perturbedgalaxies. Isolated systems appear to be smaller, less luminous and bluerthan interacting objects. We also found that bars are twice as frequentamong perturbed galaxies compared to isolated galaxies, in particularfor early Spirals and Lenticulars. The perturbed galaxies have higherLFIR/LB and Mmol/LB ratios,but the atomic gas content is similar for the two samples. The analysisof the luminosity-size and mass-luminosity relations shows similartrends for both families, the main difference being the almost totalabsence of big, bright and massive galaxies among the family of isolatedsystems, together with the almost total absence of small, faint and lowmass galaxies among the perturbed systems. All these aspects indicatethat the evolution induced by interactions with neighbors would proceedfrom late, small, faint and low mass Spirals to earlier, bigger, moreluminous and more massive spiral and lenticular galaxies, producing atthe same time a larger fraction of barred galaxies but preserving thesame relations between global parameters. The properties we found forour sample of isolated galaxies appear similar to those of high redshiftgalaxies, suggesting that the present-day isolated galaxies could bequietly evolved, unused building blocks surviving in low densityenvironments.Tables \ref{t1} and \ref{t2} are only available in electronic form athttp://www.edpsciences.org
| Starbursts in barred spiral galaxies. VI. HI observations and the K-band Tully-Fisher relation
This paper reports a study of the effect of a bar on the neutralhydrogen (HI) content of starburst and Seyfert galaxies. We also makecomparisons with a sample of ``normal'' galaxies and investigate howwell starburst and Seyfert galaxies follow the fundamental scalingTully-Fisher (TF) relation defined for normal galaxies. 111 Markarian(Mrk) IRAS galaxies were observed with the Nançay radiotelescope,and HI data were obtained for 80 galaxies, of which 64 are newdetections. We determined the (20 and 50%) linewidths, the maximumvelocity of rotation and total HI flux for each galaxy. Thesemeasurements are complemented by data from the literature to form asample of Mrk IRAS (74% starburst, 23% Seyfert and 3% unknown) galaxiescontaining 105 unbarred and 113 barred ones. Barred galaxies have lowertotal and bias-corrected HI masses than unbarred galaxies, and this istrue for both Mrk IRAS and normal galaxies. This robust result suggeststhat bars funnel the HI gas toward the center of the galaxy where itbecomes molecular before forming new stars. The Mrk IRAS galaxies havehigher bias-corrected HI masses than normal galaxies. They also showsignificant departures from the TF relation, both in the B and K bands.The most deviant points from the TF relation tend to have a strongfar-infrared luminosity and a low oxygen abundance. These resultssuggest that a fraction of our Mrk IRAS galaxies are still in theprocess of formation, and that their neutral HI gas, partly of externalorigin, has not yet reached a stationary state.Based on observations obtained at the large radiotelescope ofObservatoire de Nançay, operated by Observatoire de Paris.Tables 5 and 6 are only (and Table 4 also) available in electronic format the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/416/515
| The PDS versus Markarian starburst galaxies: comparing strong and weak IRAS emitter at 12 and 25 μm in the nearby Universe
The characteristics of the starburst galaxies from the Pico dos Diassurvey (PDS) are compared with those of the nearby ultraviolet (UV)bright Markarian starburst galaxies, having the same limit in redshift(vh < 7500 km s-1) and absolute B magnitude(MB < -18). An important difference is found: theMarkarian galaxies are generally undetected at 12 and 25 μm in IRAS.This is consistent with the UV excess shown by these galaxies andsuggests that the youngest star-forming regions dominating thesegalaxies are relatively free of dust.The far-infrared selection criteria for the PDS are shown to introduce astrong bias towards massive (luminous) and large size late-type spiralgalaxies. This is contrary to the Markarian galaxies, which are found tobe remarkably rich in smaller size early-type galaxies. These resultssuggest that only late-type spirals with a large and massive disc arestrong emitters at 12 and 25 μm in IRAS in the nearby Universe.The Markarian and PDS starburst galaxies are shown to share the sameenvironment. This rules out an explanation of the differences observedin terms of external parameters. These differences may be explained byassuming two different levels of evolution, the Markarian being lessevolved than the PDS galaxies. This interpretation is fully consistentwith the disc formation hypothesis proposed by Coziol et al. to explainthe special properties of the Markarian SBNG.
| A new catalogue of ISM content of normal galaxies
We have compiled a catalogue of the gas content for a sample of 1916galaxies, considered to be a fair representation of ``normality''. Thedefinition of a ``normal'' galaxy adopted in this work implies that wehave purposely excluded from the catalogue galaxies having distortedmorphology (such as interaction bridges, tails or lopsidedness) and/orany signature of peculiar kinematics (such as polar rings,counterrotating disks or other decoupled components). In contrast, wehave included systems hosting active galactic nuclei (AGN) in thecatalogue. This catalogue revises previous compendia on the ISM contentof galaxies published by \citet{bregman} and \citet{casoli}, andcompiles data available in the literature from several small samples ofgalaxies. Masses for warm dust, atomic and molecular gas, as well asX-ray luminosities have been converted to a uniform distance scale takenfrom the Catalogue of Principal Galaxies (PGC). We have used twodifferent normalization factors to explore the variation of the gascontent along the Hubble sequence: the blue luminosity (LB)and the square of linear diameter (D225). Ourcatalogue significantly improves the statistics of previous referencecatalogues and can be used in future studies to define a template ISMcontent for ``normal'' galaxies along the Hubble sequence. The cataloguecan be accessed on-line and is also available at the Centre desDonnées Stellaires (CDS).The catalogue is available in electronic form athttp://dipastro.pd.astro.it/galletta/ismcat and at the CDS via anonymousftp to\ cdsarc.u-strasbg.fr (130.79.128.5) or via\http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/405/5
| The cold gas properties of Markarian galaxies
A sample of 61 Markarian galaxies detected in the CO line was compiled.Using available HI, element H2, optical and radio continuumdata, the analysis of the gas kinematics and the star formationproperties for this sample of galaxies was performed. The mainconclusion can be summarized as follows: (1) The HI and CO line widthsare well correlated. Interaction between galaxies has no influence onthe CO line broadening. A rapidly rotating nuclear disk in the galaxymight lead to the CO line broadening with less influence on the HI line.(2) The atomic and molecular gas surface densities are well correlatedwith the blue, FIR and radio continuum surface brightness; however, thecorrelation for molecular component is stronger.\ (3) In general, thegalaxies with UV-excess (Markarian galaxies) do not differ in their starformation properties from the non-UV galaxies.
| 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.
| The UZC-SSRS2 Group Catalog
We apply a friends-of-friends algorithm to the combined Updated ZwickyCatalog and Southern Sky Redshift Survey to construct a catalog of 1168groups of galaxies; 411 of these groups have five or more members withinthe redshift survey. The group catalog covers 4.69 sr, and all groupsexceed the number density contrast threshold, δρ/ρ=80. Wedemonstrate that the groups catalog is homogeneous across the twounderlying redshift surveys; the catalog of groups and their membersthus provides a basis for other statistical studies of the large-scaledistribution of groups and their physical properties. The medianphysical properties of the groups are similar to those for groupsderived from independent surveys, including the ESO Key Programme andthe Las Campanas Redshift Survey. We include tables of groups and theirmembers.
| Local velocity field from sosie galaxies. I. The Peebles' model
Pratton et al. (1997) showed that the velocity field around clusterscould generate an apparent distortion that appears as tangentialstructures or radial filaments. In the present paper we determine theparameters of the Peebles' model (1976) describing infall of galaxiesonto clusters with the aim of testing quantitatively the amplitude ofthis distortion. The distances are determined from the concept of sosiegalaxies (Paturel 1984) using 21 calibrators for which the distanceswere recently calculated from two independent Cepheid calibrations. Weuse both B and I-band magnitudes. The Spaenhauer diagram method is usedto correct for the Malmquist bias. We give the equations for theconstruction of this diagram. We analyze the apparent Hubble constant indifferent regions around Virgo and obtain simultaneously the Local Groupinfall and the unperturbed Hubble constant. We found:[VLG-infall = 208 ± 9 km s-1] [\log H =1.82 ± 0.04 (H ≈ 66 ± 6 km s-1Mpc-1).] The front side and backside infalls can be seenaround Virgo and Fornax. In the direction of Virgo the comparison ismade with the Peebles' model. We obtain: [vinfall} =CVirgo/r0.9 ± 0.2] withCVirgo=2800 for Virgo and CFornax=1350 for Fornax,with the adopted units (km s-1 and Mpc). We obtain thefollowing mean distance moduli: [μVirgo=31.3 ± 0.2(r=18 Mpc )] [μFornax=31.7 ± 0.3 (r=22 Mpc). ] Allthese quantities form an accurate and coherent system. Full Table 2 isonly available in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/393/57
| X-ray luminosities of galaxies in groups
We have derived the X-ray luminosities of a sample of galaxies ingroups, making careful allowance for contaminating intragroup emission.The LX:LB and LX:LFIRrelations of spiral galaxies in groups appear to be indistinguishablefrom those in other environments, however the elliptical galaxies fallinto two distinct classes. The first class is central-dominant groupgalaxies, which are very X-ray luminous and may be the focus of groupcooling flows. All other early-type galaxies in groups belong to thesecond class, which populates an almost constant band ofLX/LB over the range9.8
| 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.
| HI observations of loose galaxy groups. I. Data and global properties
At Nançay, 21-cm H I line observations were made of 15spiral-dominated loose groups of galaxies, divided into two samples: an``interacting'' sample containing at least one pair of interactinggalaxies, and a ``control'' sample having no optical evidence ofinteractions or morphological disturbances among the group members. Theinteracting sample consists of 62 galaxies representing 9 differentgroups, and the control sample contains 40 galaxies representing 6groups. Of the 91 galaxy and galaxy pairs observed, 74 were detected,while upper limits were placed on the remaining 17 objects. Thesehomogeneous H I data, which will be used in future analyses, providecomparative information on the H I content of groups and serve as aprobe of the vicinity of the target spirals for H I clouds or very lowsurface brightness gas-rich galaxies.
| 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.
| A Dynamical Study of Galaxies in the Hickson Compact Groups
To investigate dynamical properties of spiral galaxies in the Hicksoncompact groups (HCGs), we present rotation curves of 30 galaxies in 20HCGs. We found as follows: (1) There is no significant relation betweendynamical peculiarity and morphological peculiarity in HCG spiralgalaxies. (2) There is no significant relation between the dynamicalproperties and the frequency distribution of nuclear activities in HCGspiral galaxies. (3) There are no significant correlations between thedynamical properties of HCG spiral galaxies and any group properties(i.e., size, velocity dispersion, galaxy number density, and crossingtime). (4) Asymmetric and peculiar rotation curves are more frequentlyseen in the HCG spiral galaxies than in field spiral galaxies or incluster ones. However, this tendency is more obviously seen in late-typeHCG spiral galaxies. These results suggest that the dynamical propertiesof HCG spiral galaxies do not strongly correlate with the morphology,the nuclear activity, and the group properties. Our results also suggestthat more frequent galaxy collisions occur in the HCGs than in the fieldand in the clusters.
| The Nuclear Activity of Galaxies in the Hickson Compact Groups
In order to investigate the nuclear activity of galaxies residing incompact groups of galaxies, we present results of our opticalspectroscopic program made at Okayama Astrophysical Observatory. We haveperformed optical spectroscopy of 69 galaxies belonging to 31 Hicksoncompact groups (HCGs) of galaxies. Among them, three galaxies havediscordant redshifts and, moreover, spectral quality is too poor toclassify another three galaxies. Therefore, we describe our results forthe remaining 63 galaxies. Our main results are summarized as follows:(1) We have found in our sample 28 active galactic nuclei (AGNs), 16 HII nuclei, and 19 normal galaxies showing no emission line. We used thisHCG sample for statistical analyses. (2) Comparing the frequencydistributions of activity types between the HCGs and the field galaxieswhose data are taken from Ho, Filippenko, & Sargent (382 fieldgalaxies), we find that the frequency of H II nuclei in the HCGs issignificantly less than that in the field. However, this difference maybe due to selection bias to the effect that our HCG sample contains moreearly-type galaxies than the field, because it is known that H II nucleiare rarer in early-type galaxies than in later ones. (3) Applying acorrection to this morphological bias to the HCG sample, we find thatthere is no statistically significant difference in the frequency ofoccurrence of emission-line galaxies between the HCGs and the field.This implies that the dense galaxy environment in the HCGs does notaffect the triggering of either the AGN activity and the nuclearstarburst. We discuss some implications on the nuclear activity in theHCG galaxies.
| 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.
| On the Influence of the Environment on the Star Formation Rates of a Sample of Galaxies in Nearby Compact Groups
We present the results of a study of the star formation rates (SFRs) ofa sample of disk galaxies in nearby compact groups compared with theSFRs of a sample of field galaxies. For this purpose, Hαluminosities and equivalent widths were derived for the galaxies of oursample. A direct comparison of the equivalent widths and Hαluminosities, normalized to the B luminosities and estimated area of thegalaxies of both samples, yields the result that the median values ofthese quantities are almost identical for both samples, although thedistributions for the compact-group sample are broader around the meanvalue than was found in the field galaxy sample. This result can beexplained by assuming that although interactions between galaxies incompact groups can alter the SFRs, the median value of the normalizedSFRs is preserved, being almost indistinguishable from the correspondingvalue for field galaxies. Measuring the global L_Hα/L_B of thegroups, including early-type galaxies, we find that most of the groupsthat show the highest level of L_Hα/L_B with respect to a set ofsynthetic groups built out of field galaxies show tidal features in atleast one of their members. Finally, we have explored the relationshipbetween the ratio L_Hα/L_B and several relevant dynamicalparameters of the groups: velocity dispersion, crossing time, radius,and the mass-to-luminosity ratio, finding no clear correlation. Thissuggests that the exact dynamical state of a group does not control theSFR of the group as a whole. Our results are compatible with a scenariofor compact groups of galaxies in which the dark matter of the group isarranged in a common halo, therefore preventing a fast collapse of thegalaxies.
| Investigation of Barred Galaxies. V. Surroundings of SB and SA Galaxies
Not Available
| The I-Band Tully-Fisher Relation for SC Galaxies: 21 Centimeter H I Line Data
A compilation of 21 cm line spectral parameters specifically designedfor application of the Tully-Fisher (TF) distance method is presentedfor 1201 spiral galaxies, primarily field Sc galaxies, for which opticalI-band photometric imaging is also available. New H I line spectra havebeen obtained for 881 galaxies. For an additional 320 galaxies, spectraavailable in a digital archive have been reexamined to allow applicationof a single algorithm for the derivation of the TF velocity widthparameter. A velocity width algorithm is used that provides a robustmeasurement of rotational velocity and permits an estimate of the erroron that width taking into account the effects of instrumental broadeningand signal-to-noise. The digital data are used to establish regressionrelations between measurements of velocity widths using other commonprescriptions so that comparable widths can be derived throughconversion of values published in the literature. The uniform H I linewidths presented here provide the rotational velocity measurement to beused in deriving peculiar velocities via the TF method.
| The I-Band Tully-Fisher Relation for SC Galaxies: Optical Imaging Data
Properties derived from the analysis of photometric I-band imagingobservations are presented for 1727 inclined spiral galaxies, mostly oftypes Sbc and Sc. The reduction, parameter extraction, and errorestimation procedures are discussed in detail. The asymptotic behaviorof the magnitude curve of growth and the radial variation in ellipticityand position angle are used in combination with the linearity of thesurface brightness falloff to fit the disk portion of the profile. TotalI-band magnitudes are calculated by extrapolating the detected surfacebrightness profile to a radius of eight disk scale lengths. Errors inthe magnitudes, typically ~0.04 mag, are dominated by uncertainties inthe sky subtraction and disk-fitting procedures. Comparison is made withthe similar imaging database of Mathewson, Ford, & Buchhorn, both aspresented originally by those authors and after reanalyzing theirdigital reduction files using identical disk-fitting procedures. Directcomparison is made of profile details for 292 galaxies observed incommon. Although some differences occur, good agreement is found,proving that the two data sets can be used in combination with onlyminor accommodation of those differences. The compilation of opticalproperties presented here is optimized for use in applications of theTully-Fisher relation as a secondary distance indicator in studies ofthe local peculiar velocity field.
| Starbursts in barred spiral galaxies. V. Morphological analysis of bars
We have measured the bar lengths and widths of 125 barred galaxiesobserved with CCDs. The dependence of bar strength (identified with baraxis ratio) on morphological type, nuclear activity, central and mid-barsurface brightness is investigated. The properties of the bars are bestexplained if the sample is divided into early- (< SBbc) and late-typegalaxies, and into active (starburst, Seyfert or LINER) and normalgalaxies. We find that galaxies with very long bars are mostly activeand that normal late-type galaxies have a distinct behavior from thethree other groups of galaxies. We confirm earlier findings that activelate-type galaxies tend to have both stronger and longer bars thannormal ones. An important result of this paper is that early-typegalaxies do not share this behavior: they all tend to have strong bars,whether they are active or not. We also find correlations between barstrength and relative surface brightness in the middle and at the edgeof the bar, which are not followed by normal late-type galaxies. Theseresults are interpreted in the light of recent numerical simulations andparadigms about galaxy evolution. They suggest that normal late-typegalaxies represent the first stage of galaxy evolution, and that bars inearly- and late-type galaxies do not have the same properties becausethey have a different origin. Based on observations obtained at the 2meter telescope of Observatoire du Pic du Midi, operated by INSU (CNRS)
| Atlas of H alpha Emission of a Sample of Nearby Hickson Compact Groups of Galaxies
H alpha and adjacent continuum images are presented for a sample ofnearby groups of galaxies extracted from the Atlas of Compact Groups ofGalaxies. Also, more detailed H alpha maps of the most remarkablegalaxies are shown in this paper. A short description of the H alphaemission for each of the galaxies with accordant redshift is presentedtogether with a morphological classification of the accordant galaxiesin the sample. A large fraction of ellipticals and lenticulars weredetected in H alpha . Also, clear signs of interactions were found inseven of the groups, but in only in three of them was H alpha emissiondetected along the tidal features. Candidates of dwarf galaxies werefound at the tips of the tidal tails developed during the interactionsin these three groups.
| Effects of Interaction-induced Activities in Hickson Compact Groups: CO and Far-Infrared Study
A study of 2.6 mm CO J = 1 --> 0 and far-infrared (FIR) emission in adistance-limited (z < 0.03) complete sample of Hickson compact group(HCG) galaxies was conducted in order to examine the effects of theirunique environment on the interstellar medium of component galaxies andto search for a possible enhancement of star formation and nuclearactivity. Ubiquitous tidal interactions in these dense groups wouldpredict enhanced activities among the HCG galaxies compared to isolatedgalaxies. Instead, their CO and FIR properties (thus, "star formationefficiency") are surprisingly similar to isolated spirals. The CO datafor 80 HCG galaxies presented here (including 10 obtained from theliterature) indicate that the spirals globally show the same H2 contentas the isolated comparison sample, although 20% are deficient in COemission. Because of their large optical luminosity, low metallicity isnot likely the main cause for the low CO luminosity. The CO deficiencyappears linked with the group evolution, and gas exhaustion through paststar formation and removal of the external gas reserve by tidalstripping of the outer H I disk offer a possible explanation. The IRASdata for the entire redshift-limited complete sample of 161 HCG galaxieswere reanalyzed using ADDSCAN/SCANPI, improving the sensitivity by afactor of 3-5 over the existing Point Source Catalog (PSC) and resolvingbetter the contribution from individual galaxies. The new analysis ofthe IRAS data confirms the previous suggestion that FIR emission in HCGgalaxies is similar to isolated, Virgo Cluster, and weakly interactinggalaxies. Their H2 and FIR characteristics yield a star formationefficiency that is similar to that of these comparison samples. A factor2 enhancement in the 25-100 mu m flux ratio among the HCG spirals isfound, which suggests intense localized nuclear starburst activitysimilar to that of H II galaxies. A number of early-type galaxies inHCGs are detected in CO and FIR, lending further support to the ideathat tidal interactions and tidally induced evolution of the groups andmember galaxies are important in our sample.
| Groups of galaxies. III. Some empirical characteristics.
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