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K-band observations of boxy bulges - I. Morphology and surface brightness profiles
In this first paper of a series on the structure of boxy andpeanut-shaped (B/PS) bulges, Kn-band observations of a sample of 30edge-on spiral galaxies are described and discussed. Kn-bandobservations best trace the dominant luminous galactic mass and areminimally affected by dust. Images, unsharp-masked images, as well asmajor-axis and vertically summed surface brightness profiles arepresented and discussed. Galaxies with a B/PS bulge tend to have a morecomplex morphology than galaxies with other bulge types, more oftenshowing centred or off-centred X structures, secondary maxima along themajor-axis and spiral-like structures. While probably not uniquelyrelated to bars, those features are observed in three-dimensional N-bodysimulations of barred discs and may trace the main bar orbit families.The surface brightness profiles of galaxies with a B/PS bulge are alsomore complex, typically containing three or more clearly separatedregions, including a shallow or flat intermediate region (Freeman TypeII profiles). The breaks in the profiles offer evidence for bar-driventransfer of angular momentum and radial redistribution of material. Theprofiles further suggest a rapid variation of the scaleheight of thedisc material, contrary to conventional wisdom but again as expectedfrom the vertical resonances and instabilities present in barred discs.Interestingly, the steep inner region of the surface brightness profilesis often shorter than the isophotally thick part of the galaxies, itselfalways shorter than the flat intermediate region of the profiles. Thesteep inner region is also much more prominent along the major-axis thanin the vertically summed profiles. Similarly to other recent work butcontrary to the standard `bulge + disc' model (where the bulge is boththick and steep), we thus propose that galaxies with a B/PS bulge arecomposed of a thin concentrated disc (a disc-like bulge) containedwithin a partially thick bar (the B/PS bulge), itself contained within athin outer disc. The inner disc likely formed secularly throughbar-driven processes and is responsible for the steep inner region ofthe surface brightness profiles, traditionally associated with a classicbulge, while the bar is responsible for the flat intermediate region ofthe surface brightness profiles and the thick complex morphologicalstructures observed. Those components are strongly coupled dynamicallyand are formed mostly of the same (disc) material, shaped by the weakbut relentless action of the bar resonances. Any competing formationscenario for galaxies with a B/PS bulge, which represent at least 45 percent of the local disc galaxy population, must explain equally well andself-consistently the above morphological and photometric properties,the complex gas and stellar kinematics observed, and the correlationsbetween them.
| The Survey for Ionization in Neutral Gas Galaxies. I. Description and Initial Results
We introduce the Survey for Ionization in Neutral Gas Galaxies (SINGG),a census of star formation in H I-selected galaxies. The survey consistsof Hα and R-band imaging of a sample of 468 galaxies selected fromthe H I Parkes All Sky Survey (HIPASS). The sample spans three decadesin H I mass and is free of many of the biases that affect otherstar-forming galaxy samples. We present the criteria for sampleselection, list the entire sample, discuss our observational techniques,and describe the data reduction and calibration methods. This paperfocuses on 93 SINGG targets whose observations have been fully reducedand analyzed to date. The majority of these show a single emission linegalaxy (ELG). We see multiple ELGs in 13 fields, with up to four ELGs ina single field. All of the targets in this sample are detected inHα, indicating that dormant (non-star-forming) galaxies withMHI>~3×107 Msolar are veryrare. A database of the measured global properties of the ELGs ispresented. The ELG sample spans 4 orders of magnitude in luminosity(Hα and R band), and Hα surface brightness, nearly 3 ordersof magnitude in R surface brightness and nearly 2 orders of magnitude inHα equivalent width (EW). The surface brightness distribution ofour sample is broader than that of the Sloan Digital Sky Survey (SDSS)spectroscopic sample, the EW distribution is broader than prism-selectedsamples, and the morphologies found include all common types ofstar-forming galaxies (e.g., irregular, spiral, blue compact dwarf,starbursts, merging and colliding systems, and even residual starformation in S0 and Sa spirals). Thus, SINGG presents a superior censusof star formation in the local universe suitable for further studiesranging from the analysis of H II regions to determination of the localcosmic star formation rate density.
| Measuring the fading of S0 galaxies using globular clusters
Aims. We test the hypothesis that S0 galaxies are the descendants offading spirals whose star formation has been shut down, by using theproperties of their globular cluster systems. Methods: . Weestimate the amount by which the globular cluster specific frequency(number of globular clusters per unit V-band luminosity) is enhanced inS0s relative to spirals. If the transformation hypothesis is correct,and no clusters are created or destroyed in the process, then thisdifference provides a measure of the degree to which the S0's V-bandluminosity has faded relative to that of its spiral progenitor, which wecan compare with the independent values estimated from stellarpopulation synthesis and the S0 Tully-Fisher relation. We also explorewhether the degree to which the globular cluster specific frequency isenhanced in S0s correlates with the colour of the stellar population, asalso predicted by this hypothesis in which galaxies become redder asthey fade. Results: . We find that, on average, the globularcluster specific frequency is a factor 3 larger for S0s than forspirals, which can be interpreted as meaning that passively-evolving S0shave faded on average by about a factor of three from their spiralprogenitors. This value fits remarkably well with the predictions ofstellar population synthesis calculations, and the offset between the S0and spiral Tully-Fisher relations, where the S0 V-band relation lies 1.2 mag, or a factor of three, below the spiral relation. We alsofind that the global colours of S0 galaxies are strongly correlated withtheir globular cluster specific frequencies: the redder the stellarpopulation of an S0, the larger its specific frequency, as we mightexpect if we are catching different S0s at different stages of passivelyfading and reddening. Comparison to the predictions of stellarpopulation synthesis models show that this explanation worksquantitatively as well as qualitatively. Conclusions: . Thesetests strongly support the hypothesis that S0 galaxies were once normalspirals, whose star formation was cut off, presumably due to a change ofenvironment. We are now in a position to start to make quantitativemeasurements of when this life-changing event occurred in differentgalaxies.
| Star Formation in H I-selected Galaxies. II. H II Region Properties
A sample of 69 galaxies with radial velocities less than 2500 kms-1 was selected from the H I Parkes All Sky Survey (HIPASS)to deduce details about star formation in nearby disk galaxies selectedwith no bias to optical surface brightness selection effects. Broadband(B and R) and narrowband (Hα) images were obtained for all ofthese objects. More than half of the sample galaxies are late-type,dwarf disks (mostly Sc and Sm galaxies). We have measured the propertiesof the H II regions on Hα continuum-subtracted images, using theHIIphot package developed by Thilker et al. All but one of the galaxiescontained at least one detectable H II region. Examination of theproperties of the H II regions in each galaxy revealed that thebrightest regions in higher surface brightness galaxies tend to be moreluminous than those in lower surface brightness galaxies. A higherfraction (referred to as the diffuse fraction) of the Hα emissionfrom lower surface brightness galaxies comes from diffuse ionized gas. HII region luminosity functions (LFs) co-added according to surfacebrightness show that the shapes of the LFs for the lowest surfacebrightness galaxies are different from those for typical spiralgalaxies. This discrepancy could be caused by the lowest surfacebrightness galaxies having somewhat episodic star formation or by themforming a relatively larger fraction of their stars outside of dense,massive molecular clouds. In general, the results imply that theconditions under which star formation occurs in lower surface brightnessgalaxies are different than in more typical, higher surface brightnessspiral galaxies.
| Star Formation in H I-Selected Galaxies. I. Sample Characteristics
A sample of 69 galaxies with radial velocities of less than 2500 kms-1 was selected from the H I Parkes All-Sky Survey (HIPASS)and imaged in broadband B and R and narrowband Hα, to deducedetails about star formation in nearby disk galaxies while avoidingsurface brightness selection effects. The sample is dominated bylate-type, dwarf disks (mostly Sc and Sm galaxies) with exponential diskscale lengths of ~1-5 kpc. The HIPASS galaxies, on average, have lowerstar formation rates (SFRs), are bluer, and have lower surfacebrightness than an optically selected sample. H II regions were detectedin all but one of the galaxies. Many galaxies had as few as two to fiveH II regions. The galaxies' Hα equivalent widths, colors, and SFRsper unit of H I mass are best explained by young mean ages (~3-5 Gyr,according to Schmidt-law models) with star formation histories in whichthe SFRs were higher in the past. Comparison of the surface brightnesscoverage of the HIPASS galaxies with that of an optically selectedsample shows that such a sample may miss ~10% of the local galaxy numberdensity and could possibly miss as much as 3%-4% of the SFR density. Theamount lower surface brightness galaxies contribute to the totalluminosity density may be insignificant, but this conclusion is somewhatdependent on how the fluxes of these objects are determined.
| The Globular Cluster Systems of Five Nearby Spiral Galaxies: New Insights from Hubble Space Telescope Imaging
We use available multifilter Hubble Space Telescope (HST) WFPC2 imagingof five (M81, M83, NGC 6946, M101, and M51, in order of distance)low-inclination, nearby spiral galaxies to study ancient star clusterpopulations. Combining rigorous selection criteria to rejectcontaminants (individual stars, background galaxies, and blends) withoptical photometry including the U bandpass, we unambiguously detectancient globular cluster (GC) systems in each galaxy. We presentluminosities, colors, and size (effective radius) measurements for ourcandidate GCs. These are used to estimate specific frequencies, toassess whether intrinsic color distributions are consistent with thepresence of both metal-poor and metal-rich GCs, and to compare relativesizes of ancient clusters between different galaxy systems. M81globulars have intrinsic color distributions that are very similar tothose in the Milky Way and M31, with ~40% of sample clusters havingcolors expected for a metal-rich population. The GC system in M51meanwhile, appears almost exclusively blue and metal-poor. This lack ofmetal-rich GCs associated with the M51 bulge indicates that the bulgeformation history of this Sbc galaxy may have differed significantlyfrom that of our own. Ancient clusters in M101 and possibly in NGC 6946,two of the three later type spirals in our sample, appear to haveluminosity distributions that continue to rise to our detection limit(MV~-6.0), well beyond the expected turnover(MV~-7.4) in the luminosity function. This is reminiscent ofthe situation in M33, a Local Group galaxy of similar Hubble type. Thefaint ancient cluster candidates in M101 and NGC 6946 have properties(colors and reff) similar to their more luminouscounterparts, and we suggest that these are either intermediate-age (3-9Gyr) disk clusters or the low-mass end of the original GC population.Potentially, these lower mass clusters were not destroyed because ofdifferent dynamical conditions relative to those present in earlier typegalaxies. If the faint, excess GC candidates are excluded, we find thatthe specific frequency (SN) of ancient clusters formed inlater type spirals is roughly constant, with SN=0.5+/-0.2. Ifwe consider only the blue, metal-poor clusters in the early-type spiralM81, this galaxy is also consistent with having formed a ``universal''specific frequency of halo GC population, with a value ofSN~0.6. By combining the results of this study withliterature values for other systems, we find that the total GC specificfrequencies in spirals appear to correlate best with Hubble type andbulge/total ratio, rather than with galaxy luminosity or galaxy mass.
| The 1000 Brightest HIPASS Galaxies: H I Properties
We present the HIPASS Bright Galaxy Catalog (BGC), which contains the1000 H I brightest galaxies in the southern sky as obtained from the H IParkes All-Sky Survey (HIPASS). The selection of the brightest sourcesis based on their H I peak flux density (Speak>~116 mJy)as measured from the spatially integrated HIPASS spectrum. The derived HI masses range from ~107 to 4×1010Msolar. While the BGC (z<0.03) is complete inSpeak, only a subset of ~500 sources can be consideredcomplete in integrated H I flux density (FHI>~25 Jy kms-1). The HIPASS BGC contains a total of 158 new redshifts.These belong to 91 new sources for which no optical or infraredcounterparts have previously been cataloged, an additional 51 galaxiesfor which no redshifts were previously known, and 16 galaxies for whichthe cataloged optical velocities disagree. Of the 91 newly cataloged BGCsources, only four are definite H I clouds: while three are likelyMagellanic debris with velocities around 400 km s-1, one is atidal cloud associated with the NGC 2442 galaxy group. The remaining 87new BGC sources, the majority of which lie in the zone of avoidance,appear to be galaxies. We identified optical counterparts to all but oneof the 30 new galaxies at Galactic latitudes |b|>10deg.Therefore, the BGC yields no evidence for a population of``free-floating'' intergalactic H I clouds without associated opticalcounterparts. HIPASS provides a clear view of the local large-scalestructure. The dominant features in the sky distribution of the BGC arethe Supergalactic Plane and the Local Void. In addition, one can clearlysee the Centaurus Wall, which connects via the Hydra and Antlia Clustersto the Puppis Filament. Some previously hardly noticable galaxy groupsstand out quite distinctly in the H I sky distribution. Several newstructures, including some not behind the Milky Way, are seen for thefirst time.
| Stellar Kinematics of Boxy Bulges: Large-Scale Bars and Inner Disks
Long-slit stellar kinematic observations were obtained along the majoraxis of 30 edge-on spiral galaxies, 24 with a boxy or peanut-shaped(B/PS) bulge and six with other bulge types for comparison. Such B/PSbulges are identified in at least 45% of highly inclined systems, and agrowing body of theoretical and observational work suggests that theyare the edge-on projection of thickened bars. Profiles of the meanstellar velocity V, the velocity dispersion σ, as well as theasymmetric (h3) and symmetric (h4) deviations froma pure Gaussian are presented for all objects. Comparing these profileswith stellar kinematic bar diagnostics developed from N-bodysimulations, we find bar signatures in 24 of our sample galaxies (80%).Galaxies with a B/PS bulge typically show a double-humped rotation curvewith an intermediate dip or plateau. They also frequently show a ratherflat central velocity dispersion profile accompanied by a secondary peakor plateau, and numerous galaxies have a local central σ minimum(>~40%). The h3 profiles display up to three slopereversals. Most importantly, h3 is normally correlated with Vover the presumed bar length, contrary to expectations from axisymmetricdisks. These characteristic bar signatures strengthen the case for aclose relationship between B/PS bulges and bars and leave little roomfor other explanations of the bulges' shape. We also find thath3 is anticorrelated with V in the very center of mostgalaxies (>~60%), indicating that these objects additionally harborcold and dense decoupled (quasi-) axisymmetric central stellar disks,which may be related to the central light peaks. These central diskscoincide with previously identified star-forming ionized-gas disks(nuclear spirals) in gas-rich systems, and we argue that they formed outof gas accumulated by the bar at its center through inflow. As suggestedby N-body models, the asymmetry of the velocity profile (h3)appears to be a reliable tracer of asymmetries in disks, allowing us todiscriminate between axisymmetric and barred disks seen in projection.B/PS bulges (and thus a large fraction of all bulges) appear to be madeup mostly of disk material, which has acquired a large vertical extentthrough bar-driven vertical instabilities. Their formation is thusprobably dominated by secular evolution processes rather than merging.
| The gas content of peculiar galaxies: Strongly interacting systems
A study of the gas content in 1038 interacting galaxies, essentiallyselected from Arp, Arp & Madore, Vorontsov-Velyaminov catalogues andsome of the published literature, is presented here. The data on theinterstellar medium have been extracted from a number of sources in theliterature and compared with a sample of 1916 normal galaxies. The meanvalues for each of the different ISM tracers (FIR, 21 cm, CO lines,X-ray) have been estimated by means of survival analysis techniques, inorder to take into account the presence of upper limits. From the datait appears that interacting galaxies have a higher gas content thannormal ones. Galaxies classified as ellipticals have both a dust and gascontent one order of magnitude higher than normal. Spirals have in mostpart a normal dust and HI content but an higher molecular gas mass. TheX-ray luminosity also appears higher than that of normal galaxies ofsame morphological type, both including or excluding AGNs. We consideredthe alternative possibilities that the molecular gas excess may derivefrom the existence of tidal torques which produce gas infall from thesurrounding regions or from a different metallicity which affects the Xconversion factor between the observed CO line luminosity and the H_2calculated mass. According to our tests, it appears that interactinggalaxies possess a higher molecular mass than normal galaxies but with asimilar star formation efficiency.Table 1 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/422/941
| Hubble Space Telescope observations of globular cluster systems along the Hubble sequence of spiral galaxies
We have studied the globular cluster systems of seven giant, edge-onspiral galaxies using Hubble Space Telescope imaging in V and I. Thegalaxy sample covers the Hubble types Sa to Sc, allowing us to study thevariation of the properties of globular cluster systems along the Hubblesequence. The photometry reaches ~1.5 mag beyond the turn-over magnitudeof the globular cluster luminosity function for each galaxy. Specificfrequencies of globular clusters (SN values) were evaluatedby comparing the numbers of globular clusters found in our WFPC2pointings with those in our Milky Way that would be detected in the samespatial region if placed at the distance of the target galaxies. Resultsfrom this method were found to be consistent with the more commonly usedmethod of constructing radial distribution functions of globularclusters. The SN values of spirals with B/T<~ 0.3 (i.e.spirals with a Hubble type later than about Sb) are consistent with avalue of SN= 0.55 +/- 0.25. We suggest that this populationof globular clusters represents a `universal', old halo population thatis present around each galaxy. Most galaxies in our sample haveSN values that are consistent with a scenario in whichglobular cluster systems are made up of (i) the aforementioned halopopulation plus (ii) a population that is associated with bulges, whichgrows approximately linearly with the mass of the bulge. Such scenariosinclude the `merger scenario' for the formation of elliptical galaxiesas well as the `multi-phase collapse' scenario, but it seemsinconsistent with the `secular evolution' scenario of Pfenniger &Norman, in which bulges are formed from disc stars by means of theredistribution of angular momentum through bar instabilities and/orminor perturbations. However, there is one bulge-dominated spiral galaxyin our sample (NGC7814) with a low SN value that isconsistent with those of the latest-type spirals. This means that the`secular evolution' scenario can still be viable for somebulge-dominated spirals. Thus, our results suggest that the formationhistories of galaxy bulges of early-type spirals can be significantlydifferent from one galaxy to another.
| An Hα survey aiming at the detection of extraplanar diffuse ionized gas in halos of edge-on spiral galaxies. II. The Hα survey atlas and catalog
In this second paper on the investigation of extraplanar diffuse ionizedgas in nearby edge-on spiral galaxies we present the actual results ofthe individual galaxies of our Hα imaging survey. A grand totalof 74 galaxies have been studied, including the 9 galaxies of a recentlystudied sub-sample \citep{Ro00}. 40.5% of all studied galaxies revealextraplanar diffuse ionized gas, whereas in 59.5% of the survey galaxiesno extraplanar diffuse ionized gas could be detected. The averagedistances of this extended emission above the galactic midplane rangefrom 1-2 kpc, while individual filaments in a few galaxies reachdistances of up to |z| ~ 6 kpc. In several cases a pervasive layer ofionized gas was detected, similar to the Reynolds layer in our MilkyWay, while other galaxies reveal only extended emission locally. Themorphology of the diffuse ionized gas is discussed for each galaxy andis compared with observations of other important ISM constituents in thecontext of the disk-halo connection, in those cases where publishedresults were available. Furthermore, we present the distribution ofextraplanar dust in these galaxies, based on an analysis of theunsharp-masked R-band images. The results are compared with thedistribution of the diffuse ionized gas.Based on observations collected at the European Southern Observatory,Chile (ESO No. 63.N-0070, ESO No. 64.N-0034, ESO No. 65.N.-0002).\ref{fig22}-\ref{fig54} are only available in electronic form athttp://www.edpsciences.org
| An Hα survey aiming at the detection of extraplanar diffuse ionized gas in halos of edge-on spiral galaxies. I. How common are gaseous halos among non-starburst galaxies?
In a series of two papers we present results of a new Hα imagingsurvey, aiming at the detection of extraplanar diffuse ionized gas inhalos of late-type spiral galaxies. We have investigated a sample of 74nearby edge-on spirals, covering the northern and southern hemisphere.In 30 galaxies we detected extraplanar diffuse emission at meandistances of |z| ~ 1-2 kpc. Individual filaments can be traced out to|z|<=6 kpc in a few cases. We find a good correlation between the FIRflux ratio (S60/S100) and the SFR per unit area(LFIR/D225), based on thedetections/non-detections. This is actually valid for starburst, normaland for quiescent galaxies. A minimal SFR per unit area for the lowestS60/S100 values, at which extended emission hasbeen detected, was derived, which amounts to dotEA25thres = (3.2+/-0.5)*E40ergs-1 kpc-2. There are galaxies where extraplanaremission was detected at smaller values ofLFIR/D225, however, only in combinationwith a significantly enhanced dust temperature. The results corroboratethe general view that the gaseous halos are a direct consequence of SFactivity in the underlying galactic disk.Based on observations collected at the European Southern Observatory,Chile (ESO No. 63.N-0070, ESO No. 64.N-0034, ESO No. 65.N.-0002).
| A catalog of warps in spiral and lenticular galaxies in the Southern hemisphere
A catalog of optical warps of galaxies is presented. This can beconsidered complementary to that reported by Sánchez-Saavedra etal. (\cite{sanchez-saavedra}), with 42 galaxies in the northernhemisphere, and to that by Reshetnikov & Combes(\cite{reshetnikov99}), with 60 optical warps. The limits of the presentcatalog are: logr 25 > 0.60, B_t< 14.5, delta (2000) <0deg, -2.5 < t < 7. Therefore, lenticular galaxies havealso been considered. This catalog lists 150 warped galaxies out of asample of 276 edge-on galaxies and covers the whole southern hemisphere,except the Avoidance Zone. It is therefore very suitable for statisticalstudies of warps. It also provides a source guide for detailedparticular observations. We confirm the large frequency of warpedspirals: nearly all galaxies are warped. The frequency and warp angle donot present important differences for the different types of spirals.However, no lenticular warped galaxy has been found within the specifiedlimits. This finding constitutes an important restriction fortheoretical models.
| Flat Galaxies of the RFGC Catalog Detected in the HIPASS Survey
Data from the H I Parkes All-Sky Survey (HIPASS) of the southern sky inthe neutral hydrogen line are used to determine the radial velocitiesand widths of the H I line for flat spiral galaxies of the RevisedFlat-Galaxy Catalog (RFGC) seen edge-on. The sample of 103 flat galaxiesdetected in HIPASS is characterized by a median radial velocity of +2037km/sec and a median width of the H I line at the level of 50% of maximumof 242 km/sec. For RFGC galaxies the 50% detection level in HIPASScorresponds to an apparent magnitude B t = 14 m .5 or an angulardiameter a = 2.9. The relative number of detected galaxies increasesfrom 2% for the morphological types Sbc and Sc to 41% for the type Sm.The median value of the ratio of hydrogen mass to total mass for RFGCgalaxies is 0.079. With allowance for the average internal extinctionfor edge-on galaxies, B t m .75, the median ratio of hydrogen mass toluminosity, M H I/L B = 0.74 M ȯ/L ȯ, is typical for late-typespirals. Because of its small depth, HIPASS reveals only a few RFGCgalaxies with previously unknown velocities and line widths.
| A Catalog of H I-Selected Galaxies from the South Celestial Cap Region of Sky
The first deep catalog of the H I Parkes All Sky Survey (HIPASS) ispresented, covering the south celestial cap (SCC) region. The SCC areais ~2400 deg2 and covers δ<-62°. The average rmsnoise for the survey is 13 mJy beam-1. Five hundredthirty-six galaxies have been cataloged according to their neutralhydrogen content, including 114 galaxies that have no previous catalogedoptical counterpart. This is the largest sample of galaxies from a blindH I survey to date. Most galaxies in optically unobscured regions of skyhave a visible optical counterpart; however, there is a small populationof low-velocity H I clouds without visible optical counterparts whoseorigins and significance are unclear. The rms accuracy of the HIPASSpositions is found to be 1.9′. The H I mass range of galaxiesdetected is from ~106 to ~1011 Msolar.There are a large number of late-type spiral galaxies in the SCC sample(66%), compared with 30% for optically selected galaxies from the sameregion in the NASA Extragalactic Database. The average ratio of H I massto B luminosity of the sample increases according to optical type, from1.8 Msolar/Lsolar for early types to 3.2Msolar/Lsolar for late-type galaxies. The HI-detected galaxies tend to follow the large-scale structure traced bygalaxies found in optical surveys. From the number of galaxies detectedin this region of sky, we predict the full HIPASS catalog will contain~5000 galaxies, to a peak flux density limit of ~39 mJy (3 σ),although this may be a conservative estimate as two large voids arepresent in the region. The H I mass function for this catalog ispresented in a subsequent paper.
| Warps and correlations with intrinsic parameters of galaxies in the visible and radio
From a comparison of the different parameters of warped galaxies in theradio, and especially in the visible, we find that: a) No large galaxy(large mass or radius) has been found to have high amplitude in thewarp, and there is no correlation of size/mass with the degree ofasymmetry of the warp. b) The disc density and the ratio of dark toluminous mass show an opposing trend: smaller values give moreasymmetric warps in the inner radii (optical warps) but show nocorrelation with the amplitude of the warp; however, in the externalradii is there no correlation with asymmetry. c) A third anticorrelationappears in a comparison of the amplitude and degree of asymmetry in thewarped galaxies. Hence, it seems that very massive dark matter haloeshave nothing to do with the formation of warps but only with the degreeof symmetry in the inner radii, and are unrelated to the warp shape forthe outermost radii. Denser discs show the same dependence.
| Environmental effects in galaxies. Molecular gas, star formation, and activity
In order to study whether there is any correlation between nuclearactivities, gas content, and the environment where galaxies reside, wehave obtained optical and millimetric spectra for a well-defined sampleof intermediate Hubble type spirals in dense environments and in thefield. We found that these spirals in dense environments have onaverage: less molecular gas per blue luminosity, a higher atomic gasfraction, lower current star formation rate, and the same star formationefficiency as field galaxies. Although none of these results stands outas a single strong diagnostic given their statistical significance,taken together they indicate a trend for diminished gas content andstar-formation activity in galaxies in high-density environments. Ourresults suggest that galaxies in dense environments have either (i)consumed their molecular gas via star formation in the past or (ii) thatdense environments leads to an inhibition of molecular gas from atomicphase. The similarities in star-formation efficiency of the denseenvironments and field galaxies suggest that the physical processescontroling the formation of stars from the molecular gas are localrather than global. We also found that star formation rate per blueluminosity increases linearly as the total amount of gas increases inLINERs. This result, based on a small sample, suggests that LINERs arepowered by star formation rather than an AGN. Based on observations atthe European Southern Observatory at the 15 m Swedish ESO Submillimetretelescope, SEST, and at the the 1.52 m telescope which is operated underthe ESO-ON agreement.
| Environmental effects in galaxies. The data{
We present optical and millimetric data for 47 intermediate Hubble typespiral galaxies located either in dense environments or in the field. Wecompare correlations between global parameters, such as far-infraredluminosity, blue luminosity, and total molecular gas content, with othersamples of galaxies, including normal galaxies, clusters andultraluminous infrared galaxies. We find that overall our sample is awell-defined subset of these other samples of galaxies. Based onobservations at the European Southern Observatory at the 15 m SwedishESO Submillimetre telescope, SEST, and at the the 1.52 m telescope whichis operated under the ESO-ON agreement. Appendix A is only available inelectronic form at http://www.edpsciences.org
| A list of peculiar velocities of RFGC galaxies
A list of radial velocities, HI line widths and peculiar velocities of1327 galaxies from the RFGC catalogue has been compiled using actualobservations and literature data. The list can be used for studying bulkmotions of galaxies, construction of the field of peculiar velocitiesand other tasks.
| 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
| 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.
| The Revised Flat Galaxy Catalogue.
We present a new improved and completed version of the Flat GalaxyCatalogue (FGC) named the Revised Flat Galaxy Catalogue (RFGC)containing 4236 thin edge-on spiral galaxies and covering the whole sky.The Catalogue is intended to study large-scale cosmic streamings as wellas other problems of observational cosmology. The dipole moment ofdistribution of the RFGC galaxies (l = 273 degr; b =+19 degr) lieswithin statistical errors (+/-10 degr) in the direction of the LocalGroup motion towards the Microwave Background Radiation (MBR).
| The Nature of Boxy/Peanut-Shaped Bulges in Spiral Galaxies
We present a systematic observational study of the relationship betweenbars and boxy/peanut-shaped (B/PS) bulges. We first review and discussproposed mechanisms for their formation, focusing on accretion andbar-buckling scenarios. Using new methods relying on the kinematics ofedge-on disks, we then look for bars in a large sample of edge-on spiralgalaxies with a B/PS bulge and in a smaller control sample of edge-onspirals with more spheroidal bulges. We present position-velocitydiagrams of the ionized gas obtained from optical long-slitspectroscopy. We show that almost all B/PS bulges are due to a thick barviewed edge-on, while only a few extreme cases may be due to theaccretion of external material. This strongly supports the bar-bucklingmechanism for the formation of B/PS bulges. None of the galaxies in thecontrol sample show evidence for a bar, which suggests conversely thatbars are generally B/PS.We consider the effects of dust in the disk ofthe galaxies but conclude that it does not significantly affect ourresults. Unusual emission-line ratios correlating with kinematicalstructures are observed in many objects, and we argue that this isconsistent with the presence of strong bars in the disk of the galaxies.As expected from N-body simulations, the boxy-peanut transition appearsto be related to the viewing angle, but more work is required to derivethe precise orientation of the bars in the bulges. The reliableidentification of bars in edge-on spiral galaxies opens up for the firsttime the possibility of studying observationally the vertical structureof bars.
| 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.
| Homogeneous Velocity-Distance Data for Peculiar Velocity Analysis. III. The Mark III Catalog of Galaxy Peculiar Velocities
This is the third in a series of papers in which we assemble and analyzea homogeneous catalog of peculiar velocity data. In Papers I and II, wedescribed the Tully-Fisher (TF) redshift-distance samples thatconstitute the bulk of the catalog and our methodology for obtainingmutually consistent TF calibrations for these samples. In this paper, wesupply further technical details of the treatment of the data andpresent a subset of the catalog in tabular form. The full catalog, knownas the Mark III Catalog of Galaxy Peculiar Velocities, is available inaccessible on-line databases, as described herein. The electroniccatalog incorporates not only the TF samples discussed in Papers I andII but also elliptical galaxy Dn- sigma samples originally presentedelsewhere. The relative zero pointing of the elliptical and spiral datasets is discussed here. The basic elements of the Mark III Catalog arethe observables for each object (redshift, magnitude, velocity width,etc.) and inferred distances derived from the TF or Dn- sigma relations.Distances obtained from both the forward and inverse TF relations aretabulated for the spirals. Malmquist bias--corrected distances arecomputed for each catalog object using density fields obtained from theIRAS 1.2 Jy redshift survey. Distances for both individual objects andgroups are provided. A variety of auxiliary data, including distancesand local densities predicted from the IRAS redshift surveyreconstruction method, are tabulated as well. We study the distributionsof TF residuals for three of our samples and conclude that they are wellapproximated as Gaussian. However, for the Mathewson et al. sample wedemonstrate a significant decrease in TF scatter with increasingvelocity width. We test for, but find no evidence of, a correlationbetween TF residuals and galaxy morphology. Finally, we derivetransformations that map the apparent magnitude and velocity width datafor each spiral sample onto a common system. This permits theapplication of analysis methods that assume that a unique TF relationdescribes the entire sample.
| 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.
| Recalibration of the H-0.5 magnitudes of spiral galaxies
The H-magnitude aperture data published by the Aaronson et al.collaboration over a 10 year period is collected into a homogeneous dataset of 1731 observations of 665 galaxies. Ninety-six percent of thesegalaxies have isophotal diameters and axial ratios determined by theThird Reference Cataloque of Bright Galaxies (RC3; de Vaucouleurs et al.1991), the most self-consistent set of optical data currently available.The precepts governing the optical data in the RC3 are systematicallydifferent from those of the Second Reference Catalogue (de Vaucouleurs,de Vaucouleurs, & Corwin 1976), which were used by Aaronson et al.for their original analyses of galaxy peculiar motions. This in turnleads to systematic differences in growth curves and fiducialH-magnitudes, prompting the present recalibration of the near-infraredTully-Fisher relationship. New optically normalized H-magnitude growthcurves are defined for galaxies of types SO to Im, from which new valuesof fiducial H-magnitudes, Hg-0.5, are measured forthe 665 galaxies. A series of internal tests show that these fourstandard growth curves are defined to an accuracy of 0.05 mag over theinterval -1.5 less than or equal to log (A/Dg) less than orequal to -0.2. Comparisons with the Aaronson et al. values of diameters,axial ratios, and fiducial H-magnitudes show the expected differences,given the different definitions of these parameters. The values ofHg-0.5 are assigned quality indices: a qualityvalue of 1 indicates an accuracy of less than 0.2 mag, quality 2indicates an accuracy of 0.2-0.35 mag, and quality 3 indicates anaccuracy of more than 0.35 mag. Revised values of corrected H I velocitywidths are also given, based on the new set of axial ratios defiend bythe RC3.
| Multiwavelength Energy Distributions and Bolometric Luminosities of the 12 Micron Galaxy Sample
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ...453..616S&db_key=AST
| Galaxies with f12 > f25
We have compiled a sample of galaxies whose flux density is higher at 12microns (f12) than at 25 microns (f25). It is argued thatf12 >f25effectively selects quiescent galaxies which are less active ininfrared, radio, and optical bands than other types of normal galaxies.Moreover galaxies withf12 >f25 do not exhibit the well-knownrelations that normal galaxies show between far-infrared parameters, forexample, the negative correlation betweenf12/f25 andf60/f100. Thesegalaxies also show different far-infrared and radio properties. In ouropinion this sample of quiescent galaxies is suitable for use as acontrol sample when properties of more active galaxies are discussed. Itmay also be used in modeling galaxies with active star formation or anactive nucleus.
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