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Outflows in Infrared-Luminous Starbursts at z < 0.5. II. Analysis and Discussion1,
We have performed an absorption-line survey of outflowing gas in 78starburst-dominated, infrared-luminous galaxies. This is the largeststudy of superwinds at z<~3. Superwinds are found in almost allinfrared-luminous galaxies, and changes in detection rate with SFR-windsare found twice as often in ultraluminous infrared galaxies (ULIRGs) asin less-luminous galaxies-reflect different wind geometries. The maximumvelocities we measure are 600 km s-1, though most of theoutflowing gas has lower velocities (100-200 km s-1). (Onegalaxy has velocities exceeding 1000 km s-1.) Velocities inLINERs are higher than in H II galaxies, and outflowing ionized gasoften has higher velocities than the neutral gas. Wind properties(velocity, mass, momentum, and energy) scale with galaxy properties(SFR, luminosity, and galaxy mass), consistent with ram-pressure drivingof the wind. Wind properties increase strongly with increasing galacticmass, contrary to expectation. These correlations flatten at high SFR(>~10-100 Msolar yr-1), luminosities, andmasses. This saturation is due to a lack of gas remaining in the wind'spath, a common neutral gas terminal velocity, and/or a decrease in theefficiency of thermalization of the supernovae energy. It means thatmass entrainment efficiency, rather than remaining constant, declines ingalaxies with SFR>10 Msolar yr-1 andMK<-24. Half of our sample consists of ULIRGs, which hostas much as half of the star formation in the universe at z>~1. Thepowerful, ubiquitous winds we observe in these galaxies imply thatsuperwinds in massive galaxies at redshifts above unity play animportant role in the evolution of galaxies and the intergalacticmedium.Some of the observations reported here were obtained at the MMTObservatory, which is a joint facility of the Smithsonian Institutionand the University of Arizona.Some of the observations reported here were obtained at the Kitt PeakNational Observatory, National Optical Astronomy Observatory, which isoperated by the Association of Universities for Research in Astronomy,Inc. (AURA), under cooperative agreement with the National ScienceFoundation.
| Outflows in Infrared-Luminous Starbursts at z < 0.5. I. Sample, Na I D Spectra, and Profile Fitting1,
We have conducted a spectroscopic survey of 78 starburstinginfrared-luminous galaxies at redshifts up to z=0.5. We usemoderate-resolution spectroscopy of the Na I D interstellar absorptionfeature to directly probe the neutral phase of outflowing gas in thesegalaxies. Over half of our sample are ultraluminous infrared galaxiesthat are classified as starbursts; the rest have infrared luminositiesin the range log(LIR/Lsolar)=10.2-12.0. The sampleselection, observations, and data reduction are described here. Theabsorption-line spectra of each galaxy are presented. We also discussthe theory behind absorption-line fitting in the case of a partiallycovered, blended absorption doublet observed at moderate-to-highresolution, a topic neglected in the literature. A detailed analysis ofthese data is presented in a companion paper.Some of the observations reported here were obtained at the MMTObservatory, a joint facility of the Smithsonian Institution and theUniversity of Arizona.Some of the observations reported here were obtained at the Kitt PeakNational Observatory, National Optical Astronomy Observatory, which isoperated by the Association of Universities for Research in Astronomy,Inc. (AURA), under cooperative agreement with the National ScienceFoundation.
| 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.
| The PDS versus Markarian starburst galaxies: comparing strong and weak IRAS emitter at 12 and 25 μm in the nearby Universe
The characteristics of the starburst galaxies from the Pico dos Diassurvey (PDS) are compared with those of the nearby ultraviolet (UV)bright Markarian starburst galaxies, having the same limit in redshift(vh < 7500 km s-1) and absolute B magnitude(MB < -18). An important difference is found: theMarkarian galaxies are generally undetected at 12 and 25 μm in IRAS.This is consistent with the UV excess shown by these galaxies andsuggests that the youngest star-forming regions dominating thesegalaxies are relatively free of dust.The far-infrared selection criteria for the PDS are shown to introduce astrong bias towards massive (luminous) and large size late-type spiralgalaxies. This is contrary to the Markarian galaxies, which are found tobe remarkably rich in smaller size early-type galaxies. These resultssuggest that only late-type spirals with a large and massive disc arestrong emitters at 12 and 25 μm in IRAS in the nearby Universe.The Markarian and PDS starburst galaxies are shown to share the sameenvironment. This rules out an explanation of the differences observedin terms of external parameters. These differences may be explained byassuming two different levels of evolution, the Markarian being lessevolved than the PDS galaxies. This interpretation is fully consistentwith the disc formation hypothesis proposed by Coziol et al. to explainthe special properties of the Markarian SBNG.
| Tidally Triggered Star Formation in Close Pairs of Galaxies. II. Constraints on Burst Strengths and Ages
Galaxy-galaxy interactions rearrange the baryons in galaxies and triggersubstantial star formation; the aggregate effects of these interactionson the evolutionary histories of galaxies in the universe are poorlyunderstood. We combine B- and R-band photometry and optical spectroscopyto estimate the strengths and timescales of bursts of triggered starformation in the centers of 190 galaxies in pairs and compact groups.Based on an analysis of the measured colors and EW(Hα), wecharacterize the preexisting and triggered populations separately. Thebest-fitting burst scenarios assume stronger reddening corrections forline emission than for the continuum and continuous star formationlasting for >~100 Myr. The most realistic scenarios require aninitial mass function that is deficient in the highest mass stars. Thecolor of the preexisting stellar population is the most significantsource of uncertainty. Triggered star formation contributessubstantially (probably >~50%) to the R-band flux in the centralregions of several galaxies; tidal tails do not necessarily accompanythis star formation. Many of the galaxies in our sample have bluercenters than outskirts, suggesting that pre- or nonmerger interactionsmay lead to evolution along the Hubble sequence. These objects wouldappear blue and compact at higher redshifts; the older, redder outskirtsof the disks would be difficult to detect. Our data indicate thatgalaxies with larger separations on the sky contain weaker, and probablyolder, bursts of star formation on average. However, confirmation ofthese trends requires further constraints on the colors of the olderstellar populations and on the reddening for individual galaxies.
| 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 - 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.
| 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.
| The Supernova Rate in Starburst Galaxies
We conducted an optical CCD search for supernovae in a sample of 142bright [m(B) <= 16 mag], nearby (z<=0.03) starburst galaxies overthe period 1988 December to 1991 June, to a limiting R-band magnitude of18. Five supernovae were found, in all cases outside the host galaxy'snucleus. We determine supernova rates (in supernova units or SNU) in theextranuclear regions to be 0.7 h^2 SNU for Type Ia, 0.7 h^2 SNU for TypeIb/c, and ~0.6 h^2 SNU for Type II, with large uncertainties but upperlimits of 2.2 h^2, 2.5 h^2, and 1.7 h^2 SNU, respectively. These ratesare similar to those measured in ``normal'' galaxies. We found noevidence for a supernova-induced brightening in any galactic nucleusand, with a few reasonable assumptions, can place upper limits of 9 h^2,12 h^2, and 7 h^2 SNU on the rates of unobscured supernovae Types Ia,Ib/c, and II, respectively, inside the nuclei.
| The Pico DOS Dias Survey Starburst Galaxies
We discuss the nature of the galaxies found in the Pico dos Dias Survey(PDS) for young stellar objects. The PDS galaxies were selected from theIRAS Point Source catalog. They have flux density of moderate or highquality at 12, 25, and 60 μm and spectral indices in the ranges -3.00<= alpha(25, 12) <= + 0.35 and -2.50 <= alpha(60, 25) <=+0.85. These criteria allowed the detection of 382 galaxies, which are amixture of starburst and Seyfert galaxies. Most of the PDS Seyfertgalaxies are included in the catalog of warm IRAS sources by de Grijp etal. The remaining galaxies constitute a homogeneous sample of luminous[log F (L_B/L_ȯ) = 9.9 +/- 0.4] starburst galaxies, 67% of whichwere not recognized as such before. The starburst nature of the PDSgalaxies is established by comparing their L_IR/L_B ratios and IRAScolors with a sample of emission-line galaxies from the literaturealready classified as starburst galaxies. The starburst galaxies show anexcess of FIR luminosity, and their IRAS colors are significantlydifferent from those of Seyfert galaxies-99% of the starburst galaxiesin our sample have a spectral index alpha(60, 25) < -1.9. As opposedto Seyfert galaxies, very few PDS starbursts are detected in X-rays. Inthe infrared, the starburst galaxies form a continuous sequence withnormal galaxies. But they generally can be distinguished from normalgalaxies by their spectral index alpha(60, 25) > -2.5. This colorcutoff also marks a change in the dominant morphologies of the galaxies:the normal IRAS galaxies are preferentially late-type spirals (Sb andlater), while the starbursts are more numerous among early-type spirals(earlier than Sbc). This preference of starbursts for early-type spiralsis not new, but a trait of the massive starburst nucleus galaxies(Coziol et al.). As in other starburst nucleus galaxy samples, the PDSstarbursts show no preference for barred galaxies. No difference isfound between the starbursts detected in the FIR and those detected onthe basis of UV excess. The PDS starburst galaxies represent the FIRluminous branch of the UV-bright starburst nucleus galaxies, with meanFIR luminosity log (L_IR/L_ȯ) = 10.3 +/- 0.5 and redshifts smallerthan 0.1. They form a complete sample limited in flux in the FIR at 2 x10^-10 ergs cm^-2 s^-1.
| 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.
| Optical Spectroscopy of Luminous Infrared Galaxies. II. Analysis of the Nuclear and Long-Slit Data
A spectroscopic survey of a sample of 200 luminous IRAS galaxies (LIGs:L_ir_^7^ > 3 x 10^10^ L_sun_; H_0_ = 75 km s^-1^ Mpc^-1^) was carriedout using the Palomar 5 meter and University of Hawaii 2.2 m telescopes.Kim et al. (1995) described the data-taking and data-reductionprocedures and presented line and continuum measurements extracted fromthe nucleus of these objects. In this paper, the nuclear data arecombined with circumnuclear measurements on 23 of these galaxies toinvestigate the properties of the line-emitting gas and underlyingstellar population in and out of the nucleus. The nuclear spectra ofthese galaxies were classified as H II region-like" or "AGN-like" usinga large number of line-ratio diagnostics corrected for the underlyingstellar absorption features. This correction is an important source oferrors in some previous studies. The emission-line spectra of many AGNswere found to-be of relatively low ionization level and were thereforeclassified as LINER. We confirm that both the fraction of LIGs with AGNspectra and the fraction of Seyferts among the AGN increase withinfrared luminosity, reaching values of 62% and 54% at the highestobserved luminosities, respectively. The fraction of LINERs, on theother hand, is relatively constant at ~27%. The source of the ionizationof the emission-line gas often is a function of the distance from thenucleus. Based on the emission-line ratios and the strengths of thestellar absorption features, circumnuclear starburst activity is acommon feature of LIGs, regardless of their nuclear spectral types. Theemission-line, absorption-line, continuum, radio, and IRAS properties ofthe LINERs suggest that most of the LINER emission in theseinfrared-selected galaxies is produced through shock ionization ratherthan photoionization by a genuine active nucleus. The nuclear region ofSeyfert LIGs is found to be slightly less reddened than that of theLINERs and H II galaxies. The dust distribution generally isconcentrated toward the nucleus, in agreement with the often peakydistribution of the molecular gas observed in these galaxies. Inverteddust profiles in which the nucleus appears less dusty than thecircumnuclear region are observed in only three LIGs, all of which haveAGN emission-line characteristics (one Seyfert 2 galaxy and two LINERs).Low nuclear dust content appears to favor the detection of activenuclei. This may be due to selection effects or may reflect realphysical differences between these classes of objects: galaxies withSeyfert emission lines may be at a more advanced stage of dustdestruction/expulsion than H II LIGs. Complex optical depth effects mayalso explain these results without invoking a smaller amount of dust inthe nucleus. The Hβ and Mg I b absorption features are stronger inthe nuclei of AGNs (especially among the LINERs) than in H II LIGs,suggesting that AGN LIGs are at a more advanced stage of stellarevolution than H II LIGs. Further support for this scenario comes fromthe fact that AGNs are found more frequently in advanced mergers than HII galaxies (only two Seyfert galaxies are detected in systems withwell-separated nuclei). However, this last result may be a luminosityeffect rather than an effect related to the dominant nuclear source ofionization. Moreover, the absorption-line data may simply reflect thefact that galaxies with powerful H II regions show evidence for youngstars while galaxies with AGNs do not. The radial variations of theHβ and Mg I b absorption features indicate the presence of a strongsource of featureless continuum in the nucleus of nearly all LIGs,regardless of their nuclear spectral types. Contamination by thecircumnuclear starburst prevents us from determining the extent of thiscontinuum source. The [O III] profiles of both Seyfert and LINER LIGswere found to be broader on average than those of H II objects. Nearly20% of the LIGs in our sample have line widths larger than 600 km s^-1^.We find that most of the galaxies in which we could determine the radialvariations of the [O III] line width present broader profiles in thecircumnuclear region than at the nucleus. When combined with publisheddata on a few other well-studied LIGs, these results suggest thatlarge-scale nuclear winds are common in these objects and are anefficient way of getting rid of the obscuring material in the nuclearregion. The spatially extended LINER emission observed in many of theseobjects is probably due to shock ionization resulting from theinteraction of the wind-accelerated gas with the ambient material of thehost galaxy.
| Optical Spectroscopy of Luminous Infrared Galaxies. I. Nuclear Data
A spectroscopic survey of a large sample of luminous infrared galaxies[log (L_ir_/L_sun_)^7^ ~ 10.5-12.5; H_0_ = 75 km s^-1^ Mpc^-1^] has beencarried out using the Palomar 5 m telescope,, and the University ofHawaii 2.2 m telescope. Long-slit spectra covering 375o-8000 A at aresolution of ~10 A were obtained of 200 IRAS galaxies, including 114objects from the IRAS Bright Galaxy Survey, and 86 objects with fainterinfrared fluxes selected on the basis of their "warm" far-infrared(S_60_/S_100_) colors. The methods of observation and data reduction arediscussed. An atlas of the spectra extracted from the nuclear region ofthese objects is presented along with a large number of parametersdescribing the properties of the emission lines, the stellar absorptionlines, and the continuum emission that were measured from the spectra.An analysis of these data is presented in a companion paper (Veilleux etal. 1995) along with a discussion of the spatial variations of theseparameters in a subsample of twenty-three objects.
| 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
| Radio Identifications of Extragalactic IRAS Sources
Extragalactic sources detected at λ= 60 microns were selectedfrom the IRAS Faint Source Catalog, Version 2 by the criterion S_60microns_ >= S_12_ microns. They were identified by positioncoincidence with radio sources stronger than 25 mJy at 4.85 GHz in the6.0 sr declination band 0^deg^ < δ < +75^deg^ (excluding the0.05 sr region 12^h^40^m^< α < 14^h^40^m^, 0^deg^<+5^deg^) and with radio sources stronger than 80 mJy in the 3.4 sr areao^h^ <α < 2o^h^, -40^deg^ < δ < 0^deg^ (plus theregion 12^h^40^m^ < α < 14^h^40^m^, 0^deg^<δ<+5^deg^). Fields containing new candidate identifications weremapped by the VLA at 4.86 GHz with about 15" FWHM resolution. Difficultcases were confirmed or rejected with the aid of accurate (σ ~ 1")radio and optical positions. The final sample of 354 identifications in{OMEGA} = 9.4 sr is reliable and large enough to contain statisticallyuseful numbers of radio-loud FIR galaxies and quasars. The logarithmicFIR radio flux ratio parameter q can be used to distinguish radiosources powered by "starbursts" from those powered by "monsters."Starbursts and normal spiral galaxies in a λ = 60 micronflux-limited sample have a narrow (σ_q_ = 0.14 +/- 0.01) qdistribution with mean = 2.74 +/- 0.01, and none have "warm"FIR spectra [α(25 microns, 60 microns) < 1.5]. The absence ofradio- quiet (but not completely silent) blazars indicates that nearlyall blazars become optically thin at frequencies v<~100 GHz.Nonthermal sources with steep FIR/optical spectra and dusty-embeddedsources visible only at FIR and radio wavelengths must be very rare.
| 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.
| 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.
| Northern dwarf and low surface brightness galaxies. II - The Green Bank neutral hydrogen survey
The paper reports neutral hydrogen observations of a large sample ofdwarf and other low surface brightness galaxies. A detailed discussionand error analysis of the observations are presented, and spectra aredisplayed for 329 galaxies detected for the first time, or detected withsubstantially better signal-to-noise ratios than achieved previously.The positions on the sky of 667 galaxies meeting the present selectioncriteria north of delta = 38 deg are shown. The distribution of theredshifts of galaxies detected at Green Bank is illustrated. The GreenBank detections tapered off strongly below the median H I flux of 3.7 Jykm/s detected at Arecibo: only 12 percent of the Green Bank sample wasdetected with smaller fluxes.
| Velocity differences in binary galaxies. I - Suggestions for a nonmonotonic, two-component distribution
A compilation of published high-precision velocities for 107 isolatedgalaxies is presented and used to obtain the distribution function oftheir velocity differences. The distribution shows a peak at the zerodifference as expected, but it also exhibits a preference for valuesnear 72 km/2. The distribution function declines smoothly beyond about72 km/s, with no significant peaks at multiples of 72 km/s, as claimedby Tifft (1977, 1980, 1982). It is argued that criteria for selectionprocedures on binary galaxy samples which are defined on the basis oftoo narrow a projected separation in the sky can produce a nonmonotonicdistribution if the orbits are eccentric. Such orbits can produce astrong secondary peak only if the level of incompleteness inbinary-galaxy samples is quite high, suggesting that the presentstatistical estimates of the masses of binary galaxies should bereevaluated.
| Hydroxyl in galaxies. I - Surveys with the NRAO 300 FT telescope
Results are presented of a search for 1667- and 1665-MHz mainline OHtransitions for 321 galaxies, which were observed during four separatesessions at the NRAO 300-ft telescope in the period 1984-1987. Threedetections of OH megamasers are reported, as well as detections of threenew OH absorption sources. The observational sample contains sourcesfrom a variety of catalogs and represents different criteria. Theresults for the whole sample confirm that FIR luminosity and colorcriteria used for these surveys are indeed optimized for findingmegamasers. The results also confirm that detecting distant highluminosity OH megamasers is considerably more successful than findingnearby weak masers.
| A volume-limited sample of IRAS galaxies to 4000 km/s. I - Neutral hydrogen observations from Jodrell Bank
A volume-limited catalog is constructed of normal spiral galaxies withinthe redshift interval 0-4000 km/s and brighter than 1.9 Jy at 60 micronsto study relationships between fundamental galaxy properties and to mapto the peculiar velocity field. Observations of 57 galazies are reportedfrom this sample at Jodrell Bank, 42 of which resulted in detections,and study relationships between far-IR and neutral hydrogen properties.Gas and dynamical or halo mass are well correlated with each other andmoderately so with far IR luminosity. A decrease in dynamical mass withincreasing far-color temperature suggests that less massive, later-typesystems enjoy higher specific star-formation rates.
| UGC galaxies stronger than 25 mJy at 4.85 GHz
UGC galaxies in the declination band +5 to +75 deg were identified byposition coincidence with radio sources stronger than 25 mJy on theGreen Bank 4.85 GHz sky maps. Candidate identifications were confirmedor rejected with the aid of published aperture-synthesis maps and new4.86 GHz VLA maps having 15 or 18 arcsec resolution, resulting in asample of 347 nearby radio galaxies plus five new quasar-galaxy pairs.The radio energy sources in UGC galaxies were classified as 'starbursts'or 'monsters' on the basis of their infrared-radio flux ratios, infraredspectral indices, and radio morphologies. The rms scatter in thelogarithmic infrared-radio ratio q is not more than 0.16 for starburstgalaxies selected at 4.85 GHz. Radio spectral indices were obtained fornearly all of the UGC galaxies, and S0 galaxies account for adisproportionate share of the compact flat-spectrum (alpha less than0.5) radio sources. The extended radio jets and lobes produced bymonsters are preferentially, but not exclusively, aligned within about30 deg of the optical minor axes of their host galaxies. The tendencytoward minor-axis ejection appears to be independent of radio-sourcesize and is strongest for elliptical galaxies.
| 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.
| Less probable IRR II candidateas
The paper presents a list of 89 less probable Irr candidates in whichthe presence of dust is suspected. In a commentary to this list, theshape of the galaxies is described and their location in relation toneighboring background galaxies is noted.
| 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.
| 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.
| The IRAS bright galaxy sample. II - The sample and luminosity function
A statistically complete sample of 324 of the brightest infraredgalaxies discovered at 60 microns in the IRAS all-sky survey isdescribed. The results show that far-infrared emission is a significantluminosity component in the local universe, representing 25 percent ofthe luminosity emitted by stars in the same volume. Above 10 to the 11thsolar luminosities, the infrared luminous galaxies are the dominantpopulation of objects in the universe, being as numerous as the Seyfertgalaxies and more numerous than quasars at higher luminosities. Theinfrared luminosity appears to be independent of the optical luminosityof galaxies. Most infrared bright galaxies appear to require much of theinterstellar matter to be contributing to the observed infraredluminosity. Approximately 60-80 percent of the far-infrared luminosityof the local universe can be attributed, directly or indirectly, torecent or ongoing star formation.
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