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On the alignment between binary spiral galaxies
We show some significance against the null hypothesis of randominteractions of binary spiral galaxies, and in favour of the alternativethat more interactions than expected occur for axes either nearlyparallel (spins being parallel or anti-parallel) or nearly orthogonal.We discuss this in the context of similar prior studies, using adifferent statistical focus in such a way that we are able toincorporate additional data.
| The distribution of atomic gas and dust in nearby galaxies - III. Radial distributions and metallicity gradients
The radial distribution of dust and gas in 38 nearby galaxies isinvestigated, using a sample of galaxies for which matched resolution(25 arcsec) neutral hydrogen (HI) and 850-μm images are available.Most of these radial profiles are fitted well by an exponential model,and the derived 850-μm scalelengths are proportional to the HIscalelengths. From this relation, it is found that the metallicitygradients of these galaxies are much shallower than previous studies,unless the dust temperature is constant within the disc, or asignificant component of molecular gas exists at large radii that is nottraced by CO observations.
| An IRAS High Resolution Image Restoration (HIRES) Atlas of All Interacting Galaxies in the IRAS Revised Bright Galaxy Sample
The importance of far-infrared observations for our understanding ofextreme activity in interacting and merging galaxies has beenillustrated by many studies. Even though two decades have passed sinceits launch, the most complete all-sky survey to date from which far-IRselected galaxy samples can be chosen is still that of the InfraredAstronomical Satellite (IRAS). However, the spatial resolution of theIRAS all-sky survey is insufficient to resolve the emission fromindividual galaxies in most interacting galaxy pairs, and hence previousstudies of their far-IR properties have had to concentrate either onglobal system properties or on the properties of very widely separatedand weakly interacting pairs. Using the HIRES image reconstructiontechnique, it is possible to achieve a spatial resolution ranging from30" to 1.5m (depending on wavelength and detector coverage), whichis a fourfold improvement over the normal resolution of IRAS. This issufficient to resolve the far-IR emission from the individual galaxiesin many interacting systems detected by IRAS, which is very importantfor meaningful comparisons with single, isolated galaxies. We presenthigh-resolution 12, 25, 60, and 100 μm images of 106 interactinggalaxy systems contained in the IRAS Revised Bright Galaxy Sample (RBGS,Sanders et al.), a complete sample of all galaxies having a 60 μmflux density greater than 5.24 Jy. These systems were selected to haveat least two distinguishable galaxies separated by less than threeaverage galactic diameters, and thus we have excluded very widelyseparated systems and very advanced mergers. Additionally, some systemshave been included that are more than three galactic diameters apart,yet have separations less than 4' and are thus likely to suffer fromconfusion in the RBGS. The new complete survey has the same propertiesas the prototype survey of Surace et al. We find no increased tendencyfor infrared-bright galaxies to be associated with other infrared-brightgalaxies among the widely separated pairs studied here. We find smallenhancements in far-IR activity in multiple galaxy systems relative toRBGS noninteracting galaxies with the same blue luminosity distribution.We also find no differences in infrared activity (as measured byinfrared color and luminosity) between late- and early-type spiralgalaxies.
| Dust masses and star formation in bright IRAS galaxies. Application of a physical model for the interpretation of FIR observations
We address the problem of modeling the far-infrared (FIR) spectrum andderiving the star-formation rate (SFR) and the dust mass of spiralgalaxies. We use the realistic physical model of Popescu et al.(\cite{popescu}) to describe the overall ultra-violet (UV), optical andFIR spectral energy distribution (SED) of a spiral galaxy. The modeltakes into account the 3-dimensional old and young stellar distributionsin the bulge and the disk of a galaxy, together with the dust geometry.The geometrical characteristics of the galaxy and the intrinsic opticaland near-infrared spectra are determined by the galaxy's observed K-bandphotometry. The UV part of the spectrum is assumed to be proportional tothe SFR through the use of population synthesis models. By solving theradiative transfer equation, we are able to determine the absorbedenergy, the dust temperature and the resulting FIR spectrum. The modelhas only three free parameters: SFR, dust mass, and the fraction of theUV radiation which is absorbed locally by dense dust in the HII regions.Using this model, we are able to fit well the FIR spectra of 62 brightIRAS galaxies from the ``SCUBA Local Universe Galaxy Survey" of Dunne etal. (\cite{dunne1}). As a result, we are able to determine, amongothers, their SFR and dust mass. We find that, on average, the SFR (inabsolute units), the star-formation efficiency, the SFR surface densityand the ratio of FIR luminosity over the total intrinsic luminosity, arelarger than the respective values of typical spiral galaxies of the samemorphological type. We also find that the mean gas-to-dust mass ratio isclose to the Galactic value, while the average central face-on opticaldepth of these galaxies in the V band is 2.3. Finally, we find a strongcorrelation between SFR or dust mass and observed FIR quantities liketotal FIR luminosity or FIR luminosity at 100 and 850 μm. Thesecorrelations yield well-defined relations, which can be used todetermine a spiral galaxy's SFR and dust-mass content from FIRobservations.
| The IRAS Revised Bright Galaxy Sample
IRAS flux densities, redshifts, and infrared luminosities are reportedfor all sources identified in the IRAS Revised Bright Galaxy Sample(RBGS), a complete flux-limited survey of all extragalactic objects withtotal 60 μm flux density greater than 5.24 Jy, covering the entiresky surveyed by IRAS at Galactic latitudes |b|>5°. The RBGS includes629 objects, with median and mean sample redshifts of 0.0082 and 0.0126,respectively, and a maximum redshift of 0.0876. The RBGS supersedes theprevious two-part IRAS Bright Galaxy Samples(BGS1+BGS2), which were compiled before the final(Pass 3) calibration of the IRAS Level 1 Archive in 1990 May. The RBGSalso makes use of more accurate and consistent automated methods tomeasure the flux of objects with extended emission. The RBGS contains 39objects that were not present in the BGS1+BGS2,and 28 objects from the BGS1+BGS2 have beendropped from RBGS because their revised 60 μm flux densities are notgreater than 5.24 Jy. Comparison of revised flux measurements forsources in both surveys shows that most flux differences are in therange ~5%-25%, although some faint sources at 12 and 25 μm differ byas much as a factor of 2. Basic properties of the RBGS sources aresummarized, including estimated total infrared luminosities, as well asupdates to cross identifications with sources from optical galaxycatalogs established using the NASA/IPAC Extragalactic Database. Inaddition, an atlas of images from the Digitized Sky Survey with overlaysof the IRAS position uncertainty ellipse and annotated scale bars isprovided for ease in visualizing the optical morphology in context withthe angular and metric size of each object. The revised bolometricinfrared luminosity function, φ(Lir), forinfrared-bright galaxies in the local universe remains best fit by adouble power law, φ(L)~Lα, withα=-0.6(+/-0.1) and α=-2.2(+/-0.1) below and above the``characteristic'' infrared luminosityL*ir~1010.5Lsolar,respectively. A companion paper provides IRAS High Resolution (HIRES)processing of over 100 RBGS sources where improved spatial resolutionoften provides better IRAS source positions or allows for deconvolutionof close galaxy pairs.
| The distribution of atomic gas and dust in nearby galaxies - I. Presentation of matched-resolution VLA H I and SCUBA 850-μm maps
We present matched-resolution VLA HI and SCUBA 850-μm maps of 20IRAS-bright galaxies. Of the galaxies observed, two were not detected inHI and two were detected in absorption. The HI distributions of thegalaxies have a range of morphologies. Some of the systems appear HIdeficient in the central regions which could be due to a high conversionrate of HI into molecules or HI absorption. In contrast to the HI, the850-μm emission has a smooth distribution which is concentratedtowards the optical centre of each galaxy. We also find evidence for850-μm emission extending to the periphery of the optical disc insome of the galaxies. Finally, we note that the relative lack of850-μm emission when compared with HI does not necessarily mean thatthe atomic gas and dust do not have similar mass distributions.
| The SCUBA Local Universe Galaxy Survey - II. 450-μm data: evidence for cold dust in bright IRAS galaxies
This is the second in a series of papers presenting results from theSCUBA Local Universe Galaxy Survey. In our first paper we provided850-μm flux densities for 104 galaxies selected from the IRAS BrightGalaxy Sample and we found that the 60-, 100-μm (IRAS) and 850-μm(SCUBA) fluxes could be adequately fitted by emission from dust at asingle temperature. In this paper we present 450-μm data for thegalaxies. With the new data, the spectral energy distributions of thegalaxies can no longer be fitted with an isothermal dust model - twotemperature components are now required. Using our 450-μm data andfluxes from the literature, we find that the 450/850-μm flux ratiofor the galaxies is remarkably constant, and this holds from objects inwhich the star formation rate is similar to our own Galaxy, toultraluminous infrared galaxies (ULIRGs) such as Arp 220. The onlypossible explanation for this is if the dust emissivity index for all ofthe galaxies is ~2 and the cold dust component has a similar temperaturein all galaxies [formmu3](Tc~20-21K). The 60-μmluminosities of the galaxies were found to depend on both the dust massand the relative amount of energy in the warm component, with a tendencyfor the temperature effects to dominate at the highest L60.The dust masses estimated using the new temperatures are higher by afactor of ~2 than those determined previously using a singletemperature. This brings the gas-to-dust ratios of the IRAS galaxiesinto agreement with those of the Milky Way and other spiral galaxieswhich have been intensively studied in the submm.
| The SCUBA Local Universe Galaxy Survey - I. First measurements of the submillimetre luminosity and dust mass functions
This is the first of a series of papers presenting results from theSCUBA Local Universe Galaxy Survey (SLUGS), the first statistical surveyof the submillimetre properties of the local Universe. As the initialpart of this survey, we have used the SCUBA camera on the James ClerkMaxwell Telescope to observe 104 galaxies from the IRAS Bright GalaxySample. We present here the 850-μm flux measurements. The 60-, 100-,and 850-μm flux densities are well fitted by single-temperature dustspectral energy distributions, with the sample mean and standarddeviation for the best-fitting temperature beingTd=35.6+/-4.9K and for the dust emissivity indexβ=1.3+/-0.2. The dust temperature was found to correlate with60-μm luminosity. The low value of β may simply mean that thesegalaxies contain a significant amount of dust that is colder than thesetemperatures. We have estimated dust masses from the 850-μm fluxesand from the fitted temperature, although if a colder component ataround 20K is present (assuming a β of 2), then the estimated dustmasses are a factor of 1.5-3 too low. We have made the first directmeasurements of the submillimetre luminosity function (LF) and of thedust mass function. Unlike the IRAS 60-μm LF, these are well fittedby Schechter functions. The slope of the 850-μm LF at lowluminosities is steeper than -2, implying that the LF must flatten atluminosities lower than we probe here. We show that extrapolating the60-μm LF to 850μm using a single temperature and β does notreproduce the measured submillimetre LF. A population of `cold' galaxies(Td<25K) emitting strongly at submillimetre wavelengthswould have been excluded from the 60-μm-selected sample. If suchgalaxies do exist, then this estimate of the 850-μm flux is biased(it is underestimated). Whether such a population does exist is unknownat present. We correlate many of the global galaxy properties with theFIR/submillimetre properties. We find that there is a tendency for lessluminous galaxies to contain hotter dust and to have a greater starformation efficiency (cf. Young). The average gas-to-dust ratio for thesample is 581+/-43 (using both the atomic and molecular hydrogen), whichis significantly higher than the Galactic value of 160. We believe thatthis discrepancy is probably due to a `cold dust' component atTd<=20K in our galaxies. There is a surprisingly tightcorrelation between dust mass and the mass of molecular hydrogen,estimated from CO measurements, with an intrinsic scatter of ~=50percent.
| The 1.0 Megaparsec Galaxy Pair Sample in Low-Density Regions
Using complete redshift catalogs, we have compiled a list of galaxypairs based solely on a pair's projected separation, rp, andvelocity difference, ΔV. We have made high-velocity precision H Iobservations of each galaxy in the sample and have reported these in theliterature. Due to the nature of the redshift catalogs, we are able toquantitatively evaluate the effects of isolation and number density ofsurrounding galaxies on each pair in the sample. For the close galaxypairs (rp<100 kpc), the degree of isolation (a measure ofthe number of near neighbors) has little effect on the median ΔV.This median is about 55 km s-1 for the 25 close pairs (ifmedium-density close pairs are omitted ΔV is even smaller, but thedifference is not statistically significant). The effect of isolation isstrong for the entire sample of galaxy pairs with separations as largeas 1.0 Mpc. For these larger separation pairs, relaxation of strictisolation requirements introduces small groups into the sample, whichdramatically increases the median ΔV. We find little evidence ofan increase in the median ΔV with decreasing rp, norwith increasing total luminosity. For our isolated pairs in low-densityregions, the overall median ΔV is only 30 km s-1. Forsimilar separations and isolation criteria, galaxy satellites withlarger luminosity ratios (i.e., less dynamical friction) in higherdensity regions have ΔV approximately twice as large. Weconjecture that our orbits are highly eccentric, so that the indirecteffect of dynamical friction leads to predominantly small ΔV.However, the halos of our galaxies may also be of low density (althoughhighly extended).
| 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.
| 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.
| Groups of galaxies. III. Some empirical characteristics.
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
| Kinematics of the local universe. VII. New 21-cm line measurements of 2112 galaxies
This paper presents 2112 new 21-cm neutral hydrogen line measurementscarried out with the meridian transit Nan\c cay radiotelescope. Amongthese data we give also 213 new radial velocities which complement thoselisted in three previous papers of this series. These new measurements,together with the HI data collected in LEDA, put to 6 700 the number ofgalaxies with 21-cm line width, radial velocity, and apparent diameterin the so-called KLUN sample. Figure 5 and Appendices A and B forcorresponding comments are available in electronic form at thehttp://www.edpsciences.com
| 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.
| Galaxy Pairs, Redshift Catalogs, and the Cosmic Peculiar Velocity
We discuss pairs of spiral galaxies with projected separations r_p_ranging from very wide (r_p_ ~ 1.0 Mpc) to very small (r_p_ <~ 75kpc). Single-dish H I data for the wide pairs and H I aperture synthesisas well as CCD images for the close pairs were presented in earlierpapers. From pairs (regardless of isolation criteria) in redshiftcatalogs, we find that the kinematics of spiral-spiral pairs inlow-density regions is qualitatively different from that in high-densityregions. The velocity distribution function f({DELTA}V) in low-densityregions has two components: (i) a narrow component (which is related toisolated pairs) with a very small rms value σ_v,n_ of the"one-dimensional random cosmic peculiar velocity" δν, and (ii)a broad, slowly decreasing component (which is related to pairs in loosegroups) with a large rms value of the "one-dimensional random cosmicpeculiar velocity" σnu,b_. Thus, we confirm that thedistribution of the "one- dimensional cosmic peculiar velocity"{DELTA}ν is not Gaussian and its rms value σ_V_ varies withenvironment. The median {DELTA}V_med_ of the absolute value of thevelocity difference of isolated wide pairs is ~30 km s^-1^, considerablysmaller than all estimates of σ_v_. This small {DELTA}V_med_suggests that the pairs are on low total energy, almost radial orbits,and it is also a constraint on cosmological models of structureformation. We find some circumstantial evidence for a negativecorrelation between the peculiar velocity δν and thedifferential Hubble flow velocity {DELTA}V_H_ which would be the casefor bound orbits near the maximum separation (" turnaround ``) at thecurrent epoch. If future larger samples (e.g., the CfA2 and the SSRS2surveys) confirm this, then a total galaxy mass ~10^12^ M_sun_ isimplied. All the six close pairs for which we have detailed H I andoptical CCD images show some signs of interaction, even though theselection criteria were specifically independent of known morphologicalpeculiarities. For three of the six pairs there is good evidence for thepairs also being on high eccentricity, low total energy orbits, andthere is some evidence that the impact parameter for one pair is ~1 diskradius. The median velocity difference {DELTA}V_med_ of the close pairssample is also ~30 km s^-1^. This small value of {DELTA}V_med_ isprobably an indirect effect of dynamical friction.
| Optical and I-band surface photometry of spiral galaxies. I. The data.
We present V- and I-band CCD surface photometry on 234 inclined Sa-Sdgalaxies, completed by similar data in B and R for a reduced subsample.In this first paper of a series, the reduction of the data is discussed,and several comparisons are made with other recent works. Radialprofiles are presented for the surface brightness and thecharacteristics of ellipses fitted to isophotes; global, effective, andisophotal parameters are listed. All the results are available inelectronic form.
| An image database. II. Catalogue between δ=-30deg and δ=70deg.
A preliminary list of 68.040 galaxies was built from extraction of35.841 digitized images of the Palomar Sky Survey (Paper I). For eachgalaxy, the basic parameters are obtained: coordinates, diameter, axisratio, total magnitude, position angle. On this preliminary list, weapply severe selection rules to get a catalog of 28.000 galaxies, wellidentified and well documented. For each parameter, a comparison is madewith standard measurements. The accuracy of the raw photometricparameters is quite good despite of the simplicity of the method.Without any local correction, the standard error on the total magnitudeis about 0.5 magnitude up to a total magnitude of B_T_=17. Significantsecondary effects are detected concerning the magnitudes: distance toplate center effect and air-mass effect.
| IRAS-selected Galactic star-forming regions - II. Water maser detections in the extended sample
The results of the analysis of the occurrence of 22.2-GHz H_2O maseremission in a sample of 1409 IRAS sources north of declination -30 degassociated with star-forming regions are presented. Our sample containsall the IRAS sources that satisfy Emerson criteria for selectingmolecular cores associated with the earliest evolutionary stages of thestar-forming process. In a previous paper, we have reported the resultsof the observations of about one third of the sample. In the presentpaper the observations of the remaining IRAS sources are presented: 18of them are newly detected maser sources. The results show that 20 percent of all IRAS sources that satisfy the Wood & Churchwell criteriahave H_2O water masers. This is in agreement with the assumption thatthese criteria select objects that are connected with the early phasesof the evolution of high-mass star-forming regions. Moreover, about onethird of the whole sample selected according to Emerson criteriacontains IRAS sources that are not associated with massive star-formingprocesses, but probably with molecular cores in low-mass star-formingregions.
| 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
| Dynamics of Binary Galaxies. III. Details of the Close Pairs
In a previous paper [Chengalur et al. ApJ, 107, 1984(1994)] H Isynthesis data and CCD images were presented for an objectively chosensample of six close spiral-spiral galaxy pairs. In this paper we presenta detailed analysis of the data. Although the presence of tidal featureswas not an explicit selection criterion, five of our six pairs showtidal tails and bridges. The remaining pair also shows signs ofinteraction: both galaxies in the pair have disturbed velocity fieldsand one of the two galaxies has a central concentration of molecular gasand is undergoing a starburst. The morphology of three of the six pairsimplies that the galaxies are on high eccentricity, low total energyorbits, and for one of these pairs there is some evidence that theimpact parameter is as small as ~1 disk radius. For the remaining threepairs the tidal features are not as pronounced, and the observations donot yield as much information on the orbit. However, even for thesepairs, the observed morphology is consistent with the galaxies being onslow, small impact parameter orbits, provided the galaxies are at arelatively early phase of the orbit, i.e., prior to the first closeencounter. We also find weak evidence for preferential alignment in thepairs (with the lack of preferential alignment being ruled out at the97% level), in the sense that the major axis of a galaxy tends to pointtoward the companion galaxy. This sample of close pairs is complementedby a larger sample of wide pairs (Chengalur et al. 1993). The medianvelocity difference {DELTA}V of the sample of close pairs in low-densityregions is not much different from that for the wide pairs sample, inparticular, there is no evidence for positive energy impacts. The effectof dynamical friction on infall velocities is controversial and will bediscussed in the following paper [Chengalur et al., in preparation(1995)] which combines the data on close and wide pairs.
| Dynamics of binary galaxies. 2: Close pairs
As part of a comprehensive study of binary galaxies, broadband opticalCharge Coupled Device (CCD) images and high resolution H I maps arepresented for six close pairs of spiral galaxies. A previous paperChengalur, et al., (1993) presented the results of a study of binarygalaxies with wide separations. The current sample of close pairs waschosen from the Center for Astrophysics (CfA) redshift catalog usingselection criteria that were objective and completely independent of anypreviously known morphological peculiarities. Nonetheless, all thegalaxies show some sign of interaction, implying that the selectioncriteria were sufficiently well tailored to choose physically associatedparis. All the galaxies show kinematical disturbances and haveasymmetric rotation curves. Tidal tails and bridges are clearly detectedfor some, and two pairs have a large common H I envelope. This common HI envelope also shows a large scale radial velocity gradient and givesthe impression of being in rotation about a single kinematical axis.There is relatively good agreement between the optical and H I images,with similar tidal features being seen in both. The H I features,however, extend to a much larger galactocentric radius than thecorresponding optical features. In at least one case, however, thestellar disk appears relatively normal, while the H I disk appearsdisturbed even towards the center of the galaxy. The systematic velocitydifference for the galaxy pairs has been measured quite accuratelyeither from the integrated H I spectral profile, or from a global fit tothe galaxy velocity fields. The median velocity difference for the sixgalaxy pairs is very small, approximately 20 km/s. Detailed analysis ofthe data will be presented in a separate paper.
| CO observations of Arp's interacting galaxies
We performed a (C-12)O (J= 1-0) line survey involving fifty fourinteracting galaxies from the Arp's Catalogue of Peculiar Galaxies, andcompared our results with various other data. The far infraredluminosities, as normalized by the CO luminosities, are much greater forinteracting galaxies than for normal galaxies. From correlations withthe interaction class we found that the molecular gas concentration inthe central few kpc is not necessarily enhanced by interaction. However,the efficiency of star formation from the molecular gas increasessignificantly with the interaction class, which results in an apparentincrease in the star-formation rate with the interaction class.
| The extended 12 micron galaxy sample
We have selected an all-sky (absolute value of b greater than or equalto 25 deg) 12 micron flux-limited sample of 893 galaxies from the IRASFaint Source Catalog, Version 2 (FSC-2). We have obtained accurate totalfluxes in the IRAS wavebands by using the ADDSCAN procedure for allobjects with FSC-2 12 micron fluxes greater than 0.15 Jy and increasingflux densities from 12 to 60 microns, and defined the sample by imposinga survey limit of 0.22 Jy on the total 12 micron flux. Its completenessis verified, by means of the classical log N - log S andV/Vmax tests, down to 0.30 Jy, below which we have measuredthe incompleteness down to the survey limit, using the log N - log Splot, for our statistical analysis. We have obtained redshifts (mostlyfrom catalogs) for virtually all (98.4%) the galaxies in the sample.Using existing catalogs of active galaxies, we defined a subsample of118 objects consisting of 53 Seyfert 1s and quasars, 63 Seyfert 2s, andtwo blazars (approximately 13% of the full sample), which is the largestunbiased sample of Seyfert galaxies ever assembled. Since the 12 micronflux has been shown to be about one-fifth of the bolometric flux forSeyfert galaxies and quasars, the subsample of Seyferts (includingquasars and blazars) is complete not only to 0.30 Jy at 12 microns butalso with respect to a bolometric flux limit of approximately 2.0 x10-10 ergs/s/sq cm. The average value of V/Vmaxfor the full sample, corrected for incompleteness at low fluxes, is 0.51+/- 0.04, expected for a complete sample of uniformly distributedgalaxies, while the value for the Seyfert galaxy subsample is 0.46 +/-0.10. We have derived 12 microns and far-infrared luminosity functionsfor the AGNs, as well as for the entire sample. We extracted from oursample a complete subsample of 235 galaxies flux-limited (8.3 Jy) at 60microns. The 60 micron luminosity function computed for this subsampleis in satisfactory agreement with the ones derived from the brightgalaxy sample (BGS) and the deep high-galactic latitude sample, bothselected at 60 microns.
| High resolution IRAS observations of interacting systems in the IRAS bright galaxy sample
Several conclusions have been drawn from IRAS observations and thedetermination of infrared fluxes of interacting bright galaxies. Theseare: (1) individual interacting galaxies are indistinguishable fromisolated galaxies of similar blue luminosity on the basis of infraredproperties; (2) no correlation was found between measures of interactionstrength and indicators of enhanced star formation; and (3) comparisonof the interacting and isolated samples indicates substantialdifferences between their distributions of far-infrared color ratios,luminosities, and surface brightnesses.
| The far-infrared properties of the CfA galaxy sample. I - The catalog
IRAS flux densities are presented for all galaxies in the Center forAstrophysics magnitude-limited sample (mB not greater than 14.5)detected in the IRAS Faint Source Survey (FSS), a total of 1544galaxies. The detection rate in the FSS is slightly larger than in thePSC for the long-wavelength 60- and 100-micron bands, but improves by afactor of about 3 or more for the short wavelength 12- and 25-micronbands. This optically selected sample consists of galaxies which are, onaverage, much less IR-active than galaxies in IR-selected samples. Itpossesses accurate and complete redshift, morphological, and magnitudeinformation, along with observations at other wavelengths.
| A 1.49 GHz atlas of the IRAS Bright Galaxy Sample
The VLA has been used in its A-, B-, C-, and D-configurations to make1.49 GHz maps of sources in both the original and revised IRAS BrightGalaxy Samples of strong extragalactic sources selected at a wavelengthof 60 microns. Integrated 1.49 GHz flux densities were obtained from thelowest resolution maps, and maps were made with higher resolution sothat nearly all of the radio sources have been at least partiallyresolved. Only NGC 1377 was not detected at 1.49 GHz. An atlas ofcontour maps, a table of total flux densities plus other radio sourceparameters, and references to published radio maps are given. Since theinfrared and radio continuum brightness distributions of IR-selectedgalaxies are usually similar, these high-resolution radio maps can beused as substitutes for the unavailable IR maps to indicate the sizesand precise locations of the IR-emitting regions.
| The 12 micron galaxy sample. I - Luminosity functions and a new complete active galaxy sample
An all-sky 12 micron flux-limited sample of active galaxies was selectedfrom the IRAS Point Source Catalog. Most of the sample galaxies are inexisting catalogs, and 99 percent have measured redshifts. The 12-micronand the far-infrared luminosity functions of active and normal galaxiesare derived using IRAS co-added data. A total of 22 percent of thesample galaxies harbor active nuclei. The sample consists almost equallyof Seyfert 1, Seyfert 2, and LINER nuclei. The derived luminosityfuctions for Seyfert 1 and Seyfert 2 galaxies are indistinguishable fromthose of the optically selected CfA sample. Thus, 12 micron selection isthe most efficient available technique for finding complete activegalaxy samples.
| The IRAS Bright Galaxy Sample. IV - Complete IRAS observations
Total flux densities, peak flux densities, and spatial extents at 12,25, 60, and 100 microns are presented for the 330 sources in the IRASBright Galaxy Sample. The flux density ratios Snu (60microns)/Snu (100 microns) and Snu (12microns)/Sn (25 microns) are found to correlate with both theinfrared luminosity and the ratio of IR to visible flux. The relationbetween these two flux density ratios is shown to follow that foundpreviously, with different slopes appearing for the warmer and coldergalaxies in the sample. The results suggest that single photon heatingof small grains (often the dominant source of 12 and 25 micron radiationfrom galaxies) significantly affects the emission of some galaxies at 60microns, and that optical depth effects may alter the emergent radiationat 12 and 25 microns.
| Cosmology from a galaxy group catalog. I - Binaries
A new, completely objective group-finding algorithm is described andapplied to the CfA redshift catalog. The binary galaxies are isolatedfor analysis. The assumptions underlying the analysis are (1) that lighttraces mass, (2) that our binary galaxy subsets are representative lighttracers, and (3) that the binary orbits are circular. The primary resultof the work is that the resulting bias-free binary catalogs are afunction of the assumed cosmological model. For virtually any inputvalue of Omega(0) in the range 0.01-5.00, there is a reasonablyconsistent interpretation of the CfA survey such that the specifiedvalue of Omega(0) can be derived from the binary sample obtained underthat interpretation. A secondary result is that the higher the inputvalue of Omega(0), the broader the intrinsic distribution in M/L, andhence the less valid the assumption that light traces mass.
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