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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.
| A Search for H2O Maser Emission in Southern Active Galactic Nuclei and Star-forming Galaxies: Discovery of a Maser in the Edge-on Galaxy IRAS F01063-8034
We report the cumulative results of five surveys for H2Omaser emission at 1.35 cm wavelength in 131 active galactic nuclei(AGNs) and star-forming galaxies, conducted at the Parkes Observatorybetween 1993 and 1998. We detected one new maser, in the edge-on galaxyIRAS F01063-8034, which exhibits a single ~0.1 Jy spectral feature at4282+/-6 km s-1 (heliocentric) with an unusually large54+/-16 km s-1 half-power full width. The centroid velocityof the emission increased to 4319.6+/-0.6 km s-1 (38+/-2 kms-1 width) over the 13 days between discovery andconfirmation of the detection. A similarly broad-line width and largechange in velocity has been noted for the maser in NGC 1052, wherein jetactivity excites the emission. Neither optical spectroscopy,radio-infrared correlations, nor infrared colors provide compellingevidence of unusual activity in the nucleus of IRAS F01063-8034. Sincethe galaxy appears to be outwardly normal at optical and infraredwavelengths, detection of an H2O maser therein is unique. Themaser emission is evidence that the galaxy harbors an AGN that isprobably obscured by the edge-on galactic disk. The detection highlightsthe possibility that undetected AGNs could be hidden in other relativelynearby galaxies. No other maser emission features have been identifiedat velocities between 3084 and 6181 km s-1.
| A ROSAT medium-sensitivity Galactic plane survey at 180°< l < 280°
We have performed a moderately deep soft X-ray (0.1-2keV) survey of theGalactic plane using pointed observations with the ROSAT PositionSensitive Proportional Counter (PSPC). The survey is more than an orderof magnitude more sensitive than previous X-ray surveys near theGalactic plane. The data consist of nine fields each of ~10ks exposure,pointed at positions on or very close to the Galactic plane(|b|<0°.3) in the longitude range 180°<~l<~280°.This region has relatively low X-ray absorbing material out to distancesof several hundred pc and presents fewer source-confusion problems thanat other longitudes. The total sky area surveyed was 2.5deg2this yielded 93 sources, 89 of which were detected in the `hard'(0.4-2.0keV) band. Nine sources were detected in both `soft'(0.1-0.4keV) and hard bands. In the hard band, the survey coverage is>~90 per cent for sources brighter than 0.002counts-1(~2×10-14ergcm-2s-1), but fallssteeply below this value, with the weakest sources being~0.001counts-1. The median limiting flux is~0.0013counts-1(~1.3×10-14ergcm-2s-1). There are64 sources with hard-band count rates >0.002counts-1. Wepresent the catalogue of X-ray sources and the number-flux relations(logN-logS). Eighteen sources have possible identifications from theSIMBAD data base. We have searched the Tycho-2 and USNO-A2.0 cataloguesto find all possible optical counterparts brighter than ~19th magnitude,and attempt to classify these on the basis oflog(fX/fopt) versus optical colour diagrams andnear-infrared photometry from the 2MASS Second Incremental Data Release.Hence, we have found the majority of these sources to be consistent withbeing late-type main-sequence stars, as previous studies have proposedfrom incompletely identified surveys. Comparison of the measurednumber-flux relations with predictions of Galactic (stellar) andextragalactic populations supports the view that the population of youngstars in the plane is denser than previously thought.
| On the history of the interplay between HD 56925 and NGC 2359
NGC 2359 is an optical nebula excited by the powerful wind and theradiation of the Wolf-Rayet star HD 56925. We have investigated theinteraction between this massive star and the surrounding neutral gas byanalyzing the large-scale 21 cm-Hi emission and by mapping the nebula inthe J= 1 -> 0 and the J= Hig\ lines of CO. We found a conspicuous (70x 37 pc) Hi shell, expanding at 12 km s-1, likely producedduring the main-sequence phase of the star. The molecular gas towardsNGC 2359 shows three velocity components. Two of these components, A1and A2, have narrow linewidths (1-2 km s-1) and radialvelocities of 35-38 and 64-68 km s-1, respectively. The thirdcomponent is detected at radial velocities between 50 and 58 kms-1 and has a broader profile (up to 5.5 km s-1).Furthermore, this component is morphologicaly related with the nebulaand has a velocity gradient of a few km s-1. We have alsoestimated the physical parameters of the molecular gas by means of a LVGmodelling of the CO emission. The gas projected onto the southern Hii\region of the nebula has low CO column density and is rather hot,probably up to 80 K. Several profiles of the 13CO J= 1 ->0 line near the peak of the emission, together with a weak emissionbridge between the broad and one of the narrow components (componentA2), suggest the presence of a shock front acting in the southern partof the nebula. This shock was likely produced in a previous RSG/LBVphase of HD 56925.
| 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 hard X-ray emission of luminous infrared galaxies
We present a study of the hard X-ray properties of a sample thatincludes all the Luminous Infrared Galaxies (LIGs, LIR >1011 L_sun) observed in the 2-10 keV energy band (new andarchival data). We find that a significant fraction of the sourcesoptically classified as AGNs do not show any indication of nuclearactivity in the X rays, thus suggesting heavy absorption along our lineof sight. The absence of strong emission in the 20-200 keV band in asubsample of LIGs observed with BeppoSAX suggests that in many casesthese sources are completely Compton thick (N_H > 1025cm-2). From a comparison between the infrared and the X-rayemission we deduce that the mid-IR emission is absorbed by a lowercolumn density than the X-ray emission or, alternatively, that thedust-to-gas ratio is lower than Galactic. We describe a simple modelthat reproduces the IR-X correlation by means of mixed AGN and starburstcontributions and we compare the predictions of this model with theobservational data at X-ray and optical wavelengths. Finally, we discussthe biases that affect the currently available samples of LIGs andbriefly analyze a small unbiased sample, finding that at least 50% ofthe sources host a (weak) AGN.
| ^13CO (J=1-0) Depression in Luminous Starburst Mergers, Revisited
It is known that merging galaxies with luminous starbursts and highfar-infrared luminosities tend to have higher R_1-0=^12CO (J=1-0)/^13CO(J=1-0) integrated line intensity ratios (R_1-0~=20-50) than normalspiral galaxies (R_1-0~=5-15). Comparing far-infrared luminosities[L(FIR)] with those of ^12CO (J=1-0) and ^13CO (J=1-0) for a sample ofnormal and starburst galaxies, Taniguchi & Ohyama found that theobserved high R_1-0 values for the luminous starburst mergers areattributed to their lower (by a factor of 3 on average) ^13CO lineintensities. They suggested the following two possibilities: in theluminous starburst mergers (1) ^13CO is underabundant with respect to^12CO, or (2) exitation and/or optical depth effects are responsible forthe change in R_1-0. In this paper, we investigate the secondpossibility, using higher transition data of both ^12CO and ^13COemission lines. Applying the same method proposed by Taniguchi &Ohyama to both ^12CO (J=2-1) and ^13CO (J=2-1), we find that ^13CO(J=2-1) is also depressed with respect to ^12CO (J=2-1). This suggeststhat the ^13CO gas may be underabundant in the high-R_1-0 starburstmergers, although we cannot rule out the possibility that excitation andoptical depth effects are still affecting R_2-1, for example, as aresult of the large velocity widths in the CO emission lines. Additionalobservations of both ^12CO and ^13CO lines at J>=3 are required tobetter constrain the conditions of the molecular gas in luminousstarburst galaxies.
| ^13CO (J = 1-0) Depression in Luminous Starburst Mergers
It is known that the class of luminous starburst galaxies tends to havehigher R=^12CO (J=1-0)/^13CO (J=1-0) integrated line intensity ratios(R>20) than normal spiral galaxies (R~10). Since most previousstudies investigated only R, it remains uncertain whether the luminousstarburst galaxies are overabundant in ^12CO or underabundant in ^13CO.Here we propose a new observational test to examine this problem. Ournew test is to compare far-infrared luminosities [L(FIR)] with those of^12CO and ^13CO [L(^12CO) and L(^13CO), respectively]. It is shown thatthere is a very tight correlation between L(^12CO) and L(FIR), as foundin many previous studies. However, we find that the ^13CO luminositiesof the high-R galaxies are lower by a factor of 3 on average than thoseexpected from the correlation for the remaining galaxies with ordinary Rvalues. Therefore, we conclude that the observed high R values for theluminous starburst galaxies are attributed to their lower ^13CO lineintensities.
| 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.
| Molecular hydrogen in the central regions of southern infrared galaxies
An extensive set of molecular hydrogen observations of centers ofsouthern infrared galaxies is presented. Our data are combined withpublished infrared and radio observations to investigate therelationship between nuclear and circumnuclear activity. We convert theobservational data to absolute luminosities, by applying the knowndistances. The resulting dataset covers several decades in luminosityfor the various parameters, which observe fairly tight correlations. Theparameters of our (power law) fits are, at the level of accuracyachieved, not dependent on the type of nuclear activity: while thedataset comprises a mixture of alleged Seyfert, Liner & starburstgalaxies, single fits match the complete sample well enough. Inparticular, non-thermal nuclei (AGN) present in some of the galaxies inthe current sample, do not stand out in the parameters we investigated.The absence of a significant dependence on the nuclear type isconsistent with the idea that the ever present starbursts energeticallydominate a possible `AGN in a dusty environment'-component in mostgalaxy nuclei with infrared excesses. The size of the H_2 emittingregion is found to be proportional to the square root of the 21 cm radiocontinuum luminosity. The excitation of the circumnuclear H_2 isdominated by shocks. If the H_2 extent marks the size of an inner cavityin the dense molecular material surrounding a galaxy nucleus and theradio luminosity is proportional to the mechanical luminosity of(circum)nuclear winds. This result then indicates that the cavity sizeoccurs at constant pressure in the sample galaxies, in accordance withthe superwind model by Heckman et al. (1990) [ApJS, 74, 833]. Ourresults, together with those obtained by others, thus suggest thatluminosities and size scales of excited gas associated with activenuclei are dominated by the mechanical energy input. Given thedifficulties of uniquely establishing the presence of an AGN, we cannotexclude that (a large fraction of the) infrared luminous galaxiesprocure part of their radiated energy through accretion onto a massivedark object.
| A CO survey of galaxies with the SEST and the 20-m Onsala telescope.
A large survey of galaxies in the J=1-0 CO line, performed during1985-1988 using the 15-m SEST and the 20-m millimetre wave telescope ofOnsala Space Observatory, is presented. The HPBW of the telescopes are44" and 33" at 115GHz, respectively. The central positions of 168galaxies were observed and 101 of these were detected in the CO line.More than 20% of these are new detections. Maps of some of the galaxiesare also presented.
| The Catalog of Southern Ringed Galaxies
The Catalog of Southern Ringed Galaxies (CSRG) is a comprehensivecompilation of diameters, axis ratios, relative bar position angles, andmorphologies of inner and outer rings, pseudorings, and lenses in 3692galaxies south of declination -17 deg. The purpose of the catalog is toevaluate the idea that these ring phenomena are related to orbitalresonances with a bar or oval in galaxy potentials. The catalog is basedon visual inspection of most of the 606 fields of the Science ResearchCouncil (SRC) IIIa-J southern sky survey, with the ESO-B, ESO-R, andPalomar Sky surveys used as auxiliaries when needed for overexposed coreregions. The catalog is most complete for SRC fields 1-303 (mostly southof declination -42 deg). In addition to ringed galaxies, a list of 859mostly nonringed galaxies intended for comparison with other catalogs isprovided. Other findings from the CSRG that are not based on statisticsare the identification of intrinsic bar/ring misalignment; bars whichunderfill inner rings; dimpling of R'1pseudorings; pointy, rectangular, or hexagonal inner or outer ringshapes; a peculiar polar-ring-related system; and other extreme examplesof spiral structure and ring morphology.
| The IRAS Bright Galaxy Survey - Part II: Extension to Southern Declinations (delta ~< -30), and Low Galactic Latitudes (f<|b|
Complete IRAS Observations and redshifts are reported for all sourcesidentified in the IRAS Bright Galaxy Survey-Part II (hereafter referredto as BGS_2_). Source positions, radial velocities, optical magnitudes,and total flux densities, peak flux densities, and spatial extents at12, 25, and 100 ,microns are reported for 288 sources having 60 micronflux densities > 5.24 Jy, the completeness limit of the originalBright Galaxy Survey [Soifer et al., AJ, 98,766(1989)], hereafterreferred to as BGS_1_. These new data represent the extension of theIRAS Bright Galaxy Survey to southern declinations,δ<~-30^deg^, and low Galactic latitudes,5^deg^<|b|<30^deg^. Although the sky coverage of the BGS_2_ (~19935 deg^2^) is 37% larger than the sky coverage of the BGS_1_, thenumber of sources is 8% smaller due primarily to large scale structurein the local distribution of galaxies. Otherwise, the sources in theBGS_2_ show similar relationships between number counts and flux densityas observed for the 313 sources in the BGS_1_. The BGS_2_ along with theearlier BGS, represents the best sample currently available for definingthe infrared properties of galaxies in the local (z <~ 0.1) Universe.
| Integrated photoelectric magnitudes and color indices of bright galaxies in the Johnson UBV system
The photoelectric total magnitudes and color indices published in theThird Reference Catalogue of Bright Galaxies (RC3) are based on ananalysis of approximately equals 26,000 B, 25,000 B-V, and 17,000 U-Bmultiaperture measurements available up to mid 1987 from nearly 350sources. This paper provides the full details of the analysis andestimates of internal and external errors in the parameters. Thederivation of the parameters is based on techniques described by theVaucouleurs & Corwin (1977) whereby photoelectric multiaperture dataare fitted by mean Hubble-type-dependent curves which describe theintegral of the B-band flux and the typical B-V and U-B integrated colorgradients. A sophisticated analysis of the residuals of thesemeasurements from the curves was made to allow for the random andsystematic errors that effect such data. The result is a homogeneous setof total magnitudes BTA total colors(B-V)T and (U-B)T, and effective colors(B-V)e and (U-B)e for more than 3000 brightgalaxies in RC3.
| Molecular gas in starburst galaxies: line intensities and physical conditions
In a study of molecular gas in IR-bright galaxies, we have observed thecentral position in ^12^CO J=1-0, J=2-1; ^13^CO J=1-0, J=2-1; C^18^OJ=1-0 and HCN J=1-0 line emission. The sample (in total 32 galaxies)consists of starburst galaxies, interacting galaxies and two quiescentsystems. We find a mean ^12^CO 2-1/1-0 line ratio of 0.93+/-0.22, and amean ^13^CO 2-1/1-0 line ratio of 1.3+/-0.66. The mean ^12^CO/^13^CO 1-0ratio (=R(1-0)) is =~13+/-6 and for ^12^CO/^13^CO 2-1 it is =~13+/-5.The mean ^12^CO/HCN 1-0 ratio is =~16. The ^12^CO/C^18^O 1-0 intensityratio ranges from 20 to 140 in 6 galaxies. These values of ratios referto central positions corrected for effects of beam-size and source-size.A considerable fraction of the ^13^CO emission may be saturated andoriginate in dense cores of smaller volume filling factor than thesurrounding ^12^CO-emitting gas. High gas temperatures and turbulencework against large optical depths in the ^12^CO 1-0 line of the envelopegas. In contrast to what is usually assumed for the ^12^CO 1-0 line, weinfer moderate optical depths, τ=~1, for the dominant^12^CO-emitting structure. We have found that galaxies with largeintensity ratios of [C II] 158 μm to ^12^CO 1-0 also have ^12^CO2-1/1-0 ratios >=0.8, implying that the ^12^CO-emitting gas may beboth dense and hot enough to excite the [C II] 158 μm line, acharacteristic of warm (T_k_ > 100K), photon-dominated regions. Wehave not found a correlation between the intensity ratio, I(CO)/I(HCN),and disturbed morphology, far-infrared emission, or measures ofstar-forming activity in our sample of galaxies, in contrast to thefindings of Solomon et al. (1992). The ^12^CO/HCN intensity ratio isquite uniform over a sample of 11 interacting galaxies and mergers. HCNis not detected in the one isolated spiral in the sample. Furthermore,we have observed R(1-0) in off-centre positions in 6 galaxies: NGC 1808,NGC 3256, NGC 4038/39, NGC 5055, NGC 6221 and NGC 7552. Offset positionsin the ^12^CO/^13^CO 2-1 intensity ratio have been observed in 3galaxies: NGC 660, NGC 2146 and Arp 299. We suggest that galaxies thatdisplay significant variation in the ratio, such as the merger NGC 3256,have at least two populations of molecular cloud ensembles:high-pressure clouds in the centre and an extended disk-component ofmore quiescent clouds. The molecular gas in the centres of luminousmergers with large gas surface densities (>10^4^Mȯ/pc^2^) willbe highly turbulent. In general, we suggest that R(1-0) is a measure ofthe cloud environment: the extreme values R(1-0)>20 originate inturbulent, high-pressure gas in the centres of luminous mergers;intermediate ratios 10<~R(1-0)<~15 originate in the inner kpc ofmore normal starburst galaxies; small ratios R(1-0)=~6 are a signatureof a disk population of clouds. We address the notion that abundanceanomalies cause the elevated values of R(1-0) in luminous merginggalaxies. To some extent, this notion rests on the assumption ofτ>>1 in the ^12^CO 1-0 line. We demonstrate how thisassumption may be flawed and conclude that in order to measureabundances in the molecular medium, one must carefully model thephysical properties of the molecular gas. Although abundances may beunusual in extreme mergers, they are only one aspect of the propertiesof the molecular gas in these regions.
| The RSA survey of dwarf galaxies, 1: Optical photometry
We present detailed surface photometry, based on broad B-band chargecoupled device (CCD) images, of about 80 dwarf galaxies. Our samplerepresents approximately 10% of all dwarf galaxies identified in thevicinity of Revised Shapley-Ames (RSA) galaxies on high resolution bluephotographic plates, referred to as the RSA survey of dwarf galaxies. Wederive global properties and radial surface brightness profiles, andexamine the morphologies. The radial surface brightness profiles ofdwarf galaxies, whether early or late type, display the same varietiesin shape and complexity as those of classical giant galaxies. Only a feware well described by a pure r1/4 law. Exponential profilesprevail. Features typical of giant disk galaxies, such as exponentialprofiles with a central depression, lenses, and even, in one case (IC2041), a relatively prominent bulge are also found in dwarf galaxies.Our data suggest that the central region evolves from being bulge-like,with an r1/4 law profile, in bright galaxies to a lens-likestructure in dwarf galaxies. We prove detailed surface photometry to bea helpful if not always sufficient tool in investigating the structureof dwarf galaxies. In many cases kinematic information is needed tocomplete the picture. We find the shapes of the surface brightnessprofiles to be loosely associated with morphological type. Our samplecontains several new galaxies with properties intermediate between thoseof giant and dwarf ellipticals (but no M32-like objects). This showsthat such intermediate galaxies exist so that at least a fraction ofearly-type dwarf ellipticals is structurally related to early-typegiants instead of belonging to a totally unrelated, disjunct family.This supports an origin of early-type dwarf galaxies as originally moremassive systems that acquired their current morphology as a result ofsubstantial, presumable supernova-driven, mass loss. On the other hand,several early-type dwarfs in our sample are merger candidates. Mergerevents may lead to anisotropic velocity distributions in systems of anyluminosity, including dwarfs. The RSA sample of dwarf galaxies is morelikely to contain mergers because, in contrast to earlier dwarf galaxysurveys that have focused on clusters and rich groups of galaxies, theRSA dwarfs are typically located in low density environments. Theoccurrence of mergers among dwarf galaxies is of interest in connectionwith the rapid evolution of faint blue galaxy counts at redshift z lessthan 1 which suggests that dwarf galaxies were about five times morenumerous in the recent past.
| A volume-limited sample of IRAS galaxies to 4000 km/s, 3: CCD photometry from Palomar and Tololo observatories
An all-sky, quasi-volume-limited sample of 251 spiral galaxies within4000 km/s has been extracted from the redshift survey of InfraredAstronomy Satellite (IRAS) galaxies by Strauss (1992). Distance modulifor these objects estimated via the Tully-Fisher (TF) method allow thepeculiar velocity field and the cosmological density parameter to beconstrained within this volume. The TF relation we exploit relatesdeprojected neutral hydrogen line width to near-infrared luminosity.Herein we present I and V band photometry for 159 members of this sampleobtained with charge coupled device (CCD) cameras at Palomar and Tololoobservatories. Image processing and photometric calibration proceduresare described. Twenty seven objects with multiple calibratedobservations suggest that isophotal I band magnitudes are reproduced toequal to or less than 0.05 mag precision at sigmaI = 23.5 magarcsec-2, and that systematic run-to-run offsets are limitedto equal to or less than 0.05 I mag.
| A volume-limited sample of IRAS galaxies to 4000 km/s, 2: Neutral hydrogen observations from the Parkes telescope
We have extracted a volume-limited sample of spiral galaxies within 4000km/s from the Strauss et al. (1992) redshift survey of InfraredAstronomical Satellite (IRAS) galaxies. The purpose of the sample is touse distances obtained from the neutral hydrogen/near-infrared (I-band)Tully-Fisher relation to study deviations from uniform Hubble expansion.This will allow us to estimate the distribution of mass in the localuniverse and to place constraints on the value of the cosmologicaldensity parameter, omega 0. Here we report neutral hydrogen(H I) observations of 61 galaxies from this sample taken at the 64 mParkes telescope, 48 of which resulted in measured linewidth parameters.Empirical estimates of random and systematic errors in H I line widthsat low signal-to-noise ratio are described.
| IRAS CPC Observations of Galaxies - Part One - Catalog and Atlas
. - We present the results of far-infrared imaging observations of 258regions of 12' x9' each centered on a selected individual galaxy, aclose pair, or a compact group of galaxies mapped at 50 and 100 micronwavelength with the CPC instrument of the IRAS satellite. The CPCinstrument has a significantly better resolution than the IRAS Surveyinstrument at these wavelengths, i.e. a round beam with a FWHM of about80" at 50 microns and 95" at 100 microns, respectively, intended to bematched to the diffraction limit of the telescope at 100 microns. Themaps were made using a new algorithm to correct for gain variations,which gives better results than the one used previously for the imagesmade available on tape in 1985. Of 262 objects observed, 167 and 188were detected at 50 and 100 microns, respectively, about 85% of thegalaxies from the same sample listed as detected by the Surveyinstrument in the IRAS Point Source Catalog. For all 55 galaxiesresolved (i.e. with a FWHM major axis diameter exceeding 1.6 times thebeam FWHM and/or extended lower-level emission) by the CPC we alsopresent the averaged maps at 50 and 100 microns. These 55 objectsinclude 35 for which there are no published maps obtained with the IRASSurvey instrument. We rescaled the flux densities of the published CPCmaps using the more accurate IRAS Survey instrument data, since theabsolute flux density calibration of the CPC is only accurate to about+/-60%. We also present images of a triplet of galaxies associated witha single Survey point source, which were resolved into separate sourcesby the CPC.
| General study of group membership. II - Determination of nearby groups
We present a whole sky catalog of nearby groups of galaxies taken fromthe Lyon-Meudon Extragalactic Database. From the 78,000 objects in thedatabase, we extracted a sample of 6392 galaxies, complete up to thelimiting apparent magnitude B0 = 14.0. Moreover, in order to considersolely the galaxies of the local universe, all the selected galaxieshave a known recession velocity smaller than 5500 km/s. Two methods wereused in group construction: a Huchra-Geller (1982) derived percolationmethod and a Tully (1980) derived hierarchical method. Each method gaveus one catalog. These were then compared and synthesized to obtain asingle catalog containing the most reliable groups. There are 485 groupsof a least three members in the final catalog.
| Co/ 2-1 and 13/CO/ 1-0 Emission from Luminous Southern Infrared Galaxies
, We observed, using the SEST 15-m telescope, the CO(2-1) line emissiontoward eight highly luminous infrared galaxies of the southernhemisphere which were previously detected in the CO(1-0) transition.While the shapes of the (2 - 1) and (1 - 0) line profiles (taken withangular resolutions of 24" and 45", respectively) are remarkablysimilar, the ratios of observed peak main-beam radiation temperaturesvary between 1.2 and 2.6. The derived (2-1)/(1-0) ratios of velocityintegrated brightness temperature range between 0.33 and 0.77,indicating that the physical conditions of the molecular gas varies fromsource to source. Assuming that the kinetic temperature of the moleculargas is similar to the temperature derived for the dust (~30-40 K), thelow values of the integrated line ratios imply that the CO issubthermally excited and that the bulk of the emission arises fromregions of moderate H_2_ density, between 100 and 500 cm^-3^. We findthat the use of the Galactic CO-H_2_ conversion factor is appropriate,to within a factor of 1.5, to estimate the molecular mass in this typeof galaxies. We also observed four of these galaxies in the ^13^CO(1-0)transition and one in the ^13^CO(2-1) line. The ^12^CO(1-0)/^13^CO(1-0)velocity integrated brightness temperature ratios range from 9 to 27.The largest values, about 5 times greater than the average ratioobserved for molecular clouds in the Milky Way disk, are exhibited bythe most luminous IR galaxies. They can be explained if molecular cloudsin mergers have low and moderate optical depths in ^13^CO and ^12^CO,respectively.
| IRAS LRS spectroscopy of galaxies
The study presents IRAS LRS data for 350 galaxies with pointlike IRASsources having either S(12) or S(25) not less than 1.5 Jy. Techniquesare presented which form the mean of an ensemble of LRS spectra, ll ofwhich are only of low signal-to-noise ratio, by quantitative evaluationof the significance of the individual spectra for each object ratherthan mere acceptance of the 'average spectrum' present in the completeLRS data base. Average LRS spectra for groups of galaxies with distinctoptical nuclear properties are formed. Average LRS spectra for severalcategories of objects are presented and interpreted. H II regiongalaxies show the polycyclic aromatic hydrocarbon spectrum of bands inemissions; type 2 Seyferts present a broad emission feature parking near16 microns; LINERs and galaxies without optical emission lines have LRSspectra that decline with wavelength, whereas type 1 Seyferts and WRgalaxies have red spectra suggestive of nonthermal emission processes.
| Groups of galaxies within 80 Mpc. II - The catalogue of groups and group members
This paper gives a catalog of the groups and associations obtained bymeans of a revised hierarchical algorithm applied to a sample of 4143galaxies with diameters larger than 100 arcsec and redshifts smallerthan 6000 km/s. The 264 groups of galaxies obtained in this way (andwhich contain at least three sample galaxies) are listed, with the looseassociations surrounding them and the individual members of eachaggregate as well; moreover, the location of every entity among 13regions corresponding roughly to superclusters is specified. Finally,1729 galaxies belong to the groups, and 466 to the associations, i.e.,the total fraction of galaxies within the various aggregates amounts to53 percent.
| CO(1-0) emission from luminous infrared galaxies in the southern hemisphere
CO (1-0) emission was detected from 28 high luminosity IRAS galaxies inthe southern sky, selected from a sample of galaxies with 60 micron IRASfluxes over 4.5 Jy and IR luminosities over 10 to the 11th solar. Thesegalaxies have total masses of H2 in the range of 0.6-6 x 10 to the 10thsolar mass, namely 2-20 times the mass of molecular gas in the Galaxy.The IR luminosities per nucleon of molecular gas, L(IR)/M (H2), are inthe range of 10-80 L(solar)/M(solar). This is 5-40 times the globalvalue of this ratio in the Galaxy averaged over the whole disk. Theoptical morphology and the large masses of molecular gas found among the12 galaxies of this sample with L(IR) over 10 to the 12th L(solar)suggest that ultraluminous IR galaxies are mergers of giant spiralgalaxies.
| Models for infrared emission from IRAS galaxies
The far-infrared spectra of galaxies detected in four wavelength bandsby IRAS have been modeled in terms of a cool disk component, a warmerstarburst component, and a Seyfert component peaking at 25 microns.Although the models are found to fit the observed spectra of non-Seyfertand several Seyfert galaxies, a more complex geometry for the dustdistribution is indicated for NGC 1068 and many other Seyfert galaxies.In some cases, the dust in the narrow-line region has a nonsphericallysymmetric geometry.
| A search for megamaser galaxies
The results of a search for OH megamaser emission from a sample of 32galaxies selected from the IRAS Point Source Catalog on the basis oftheir IR properties are presented. For each galaxy (other than those fewalready observed elsewhere), an optical redshift is obtained and both OHand H I emission are sought. The search yielded one new OH megamasergalaxy, and H I was detected toward nine objects. There are unlikely tobe any OH megamasers in the Southern Hemisphere with flux densitiescomparable to that of Arp 220 (280 mJy), although there may be apopulation of weaker megamasers. No special conditions are required toexplain the known OH megamasers other than those expected in a cool,dusty, active galaxy.
| Simulated aperture-photometry on CCD-frames for 67 southern galaxies in B and R
As part of a large project to calibrate all the Schmidt plates of theESO Quick blue and the red survey, CCD-photometry in B and R has beenobtained for galaxies on 67 different survey fields. On these framessynthetic-aperture photometry is applied in order to present the data ina way which makes the comparison with photographic photometry easy.
| A case for H0 = 42 and Omega(0) = 1 using luminous spiral galaxies and the cosmological time scale test
The two principal methods of finding the Hubble velocity-distance ratiosfor individual galaxies are compared, and it is shown that one route toH0 is flawed by selection effects when using flux-limited catalogs. Theproof is made by analyzing two sets of catalogs that reach differentapparent flux levels, so that selection effects are shown directly. Theoptical data on field spiral galaxies of the brightest van den Berghluminosity class are analyzed. Calibration using M31, M81, and M101which have Cepheid distances gives H0 = 42 + or - 11 km/s/Mpc. It isshown that all values of H0 derived by the method of assigning a fixedabsolute magnitude to any given distance indicator is subject tosystematic error, giving too large an H0 value if uncorrected for bias.The age of the globular clusters is adopted to be 13.5 + or - 1 Gyr, andthe age of the universe is put at 14.9 + or - 2 Gyr. A value of Omega(0)= 1.2 + 3 or - 0.9 with Lambda = 0 is obtained.
| Southern Galaxy Catalogue.
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