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The AMIGA sample of isolated galaxies. II. Morphological refinement
We present a refinement of the optical morphologies for galaxies in theCatalog of Isolated Galaxies that forms the basis of the AMIGA (Analysisof the interstellar Medium of Isolated GAlaxies) project. Uniformreclassification using the digitized POSS II data benefited from thehigh resolution and dynamic range of that sky survey. Comparison withindependent classifications made for an SDSS overlap sample of more than200 galaxies confirms the reliability of the early vs. late-typediscrimination and the accuracy of spiral subtypes within Δ T =1-2. CCD images taken at the Observatorio de Sierra Nevada were alsoused to solve ambiguities in early versus late-type classifications. Aconsiderable number of galaxies in the catalog (n = 193) are flagged forthe presence of nearby companions or signs of distortion likely due tointeraction. This most isolated sample of galaxies in the local Universeis dominated by two populations: 1) 82% are spirals (Sa-Sd) with thebulk being luminous systems with small bulges (63% between types Sb-Sc)and 2) a significant population of early-type E-S0 galaxies (14%). Mostof the types later than Sd are low luminosity galaxies concentrated inthe local supercluster where isolation is difficult to evaluate. Thelate-type spiral majority of the sample spans a luminosity rangeMB-corr = -18 to -22 mag. Few of the E/S0 population are moreluminous than -21.0 marking the absence of the often-sought superL* merger (e.g. fossil elliptical) population. The rarity ofhigh luminosity systems results in a fainter derived M* forthis population compared to the spiral optical luminosity function(OLF). The E-S0 population is from 0.2 to 0.6 mag fainter depending onhow the sample is defined. This marks the AMIGA sample as unique amongsamples that compare early and late-type OLFs separately. In othersamples, which always involve galaxies in higher density environments,M^*_E/S0 is almost always 0.3-0.5 mag brighter than M^*_S, presumablyreflecting a stronger correlation between M* andenvironmental density for early-type galaxies.
| Measuring shapes of galaxy images - II. Morphology of 2MASS galaxies
We study a sample of 112 galaxies of various Hubble types imaged in theTwo Micron All Sky Survey (2MASS) in the near-infrared (NIR; 1-2 μm)J, H and Ks bands. The sample contains (optically classified)32 ellipticals, 16 lenticulars and 64 spirals acquired from the 2MASSExtended Source Catalogue (XSC).We use a set of non-parametric shape measures constructed from theMinkowski functionals (MFs) for galaxy shape analysis. We useellipticity (ɛ) and orientation angle (Φ) as shapediagnostics. With these parameters as functions of area within theisophotal contour, we note that the NIR elliptical galaxies withɛ > 0.2 show a trend of being centrally spherical andincreasingly flattened towards the edge, a trend similar to images inoptical wavelengths. The highly flattened elliptical galaxies showstrong change in ellipticity between the centre and the edge. Thelenticular galaxies show morphological properties resembling eitherellipticals or disc galaxies. Our analysis shows that almost half of thespiral galaxies appear to have bar-like features while the rest arelikely to be non-barred. Our results also indicate that almost one-thirdof spiral galaxies have optically hidden bars.The isophotal twist noted in the orientations of elliptical galaxiesdecreases with the flattening of these galaxies, indicating that twistand flattening are also anticorrelated in the NIR, as found in opticalwavelengths. The orientations of NIR lenticular and spiral galaxies showa wide range of twists.
| Revised positions for CIG galaxies
We present revised positions for the 1051 galaxies belonging to theKarachentseva Catalog of Isolated Galaxies (CIG). New positions werecalculated by applying SExtractor to the Digitized Sky Survey CIG fieldswith a spatial resolution of 1 arcsper 2. We visually checked theresults and for 118 galaxies had to recompute the assigned positions dueto complex morphologies (e.g. distorted isophotes, undefined nuclei,knotty galaxies) or the presence of bright stars. We found differencesbetween older and newer positions of up to 38 arcsec with a mean valueof 2 arcsper 96 relative to SIMBAD and up to 38 arcsec and 2 arcsper 42respectively relative to UZC. Based on star positions from the APMcatalog we determined that the DSS astrometry of five CIG fields has amean offset in (alpha , delta ) of (-0 arcsper 90, 0 arcsper 93) with adispersion of 0 arcsper 4. These results have been confirmed using the2MASS All-Sky Catalog of Point Sources. The intrinsic errors of ourmethod combined with the astrometric ones are of the order of 0 arcsper5.Full Table 1 is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/411/391
| 12CO(1-0) observation of isolated late-type galaxies
We present 12CO(J=1-0) line observations of 99 galaxiesobtained with the SEST 15 m, the Kitt Peak 12 m and the IRAM 30 mtelescopes. The target galaxies were selected from the catalogue ofisolated galaxies of Karachentseva (\cite{Karachentseva73}). These dataare thus representative of the CO properties of isolated late-typegalaxies. All objects were observed in their central position, thosewith large angular sizes were mapped. These new measurements are used toestimate the molecular gas mass of the target galaxies. The moleculargas is on average ~ 18% of the atomic gas mass.Tables 1 and 2 are also available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/411/381Based on observations made with the 12-m National Radio AstronomicalObservatory, Kitt Peak, Arizona, with the Swedish-ESO Submillimetretelescope SEST, La Silla, Chile, with the IRAM 30 m radiotelescope, PicoVeleta, Granada, Spain.
| A test of arm-induced star formation in spiral galaxies from near-infrared and Hα imaging
We have imaged a sample of 20 spiral galaxies in Hα and in thenear-infrared K band (2.2 μm), in order to determine the location andstrength of star formation in these objects with respect toperturbations in the old stellar population. We have found that starformation rates are significantly enhanced in the vicinity of K-bandarms. We have also found that this enhancement in star formation rate inarm regions correlates well with a quantity that measures the relativestrengths of shocks in arms. Assuming that the K-band light is dominatedby emission from the old stellar population, this shows that densitywaves trigger star formation in the vicinity of spiral arms.
| 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 structure of spiral galaxies - II. Near-infrared properties of spiral arms
We have imaged a sample of 45 face-on spiral galaxies in the K band, todetermine the morphology of the old stellar population, which dominatesthe mass in the disc. The K-band images of the spiral galaxies have beenused to calculate different characteristics of the underlying densityperturbation such as arm strengths, profiles and cross-sections, andspiral pitch angles. Contrary to expectations, no correlation was foundbetween arm pitch angle and Hubble type, and combined with previousresults this leads us to conclude that the morphology of the old stellarpopulation bears little resemblance to the optical morphology used toclassify galaxies. The arm properties of our galaxies seem inconsistentwith predictions from the simplest density wave theories, and someobservations, such as variations in pitch angle within galaxies, seemhard to reconcile even with more complex modal theories. Bars have nodetectable effect on arm strengths for the present sample. We have alsoobtained B-band images of three of the galaxies. For these galaxies wehave measured arm cross-sections and strengths, to investigate theeffects of disc density perturbations on star formation in spiral discs.We find that B-band arms lead K-band arms and are narrower than K-bandarms, apparently supporting predictions made by the large-scale shockscenario, although the effects of dust on B-band images may contributetowards these results.
| The structure of spiral galaxies - I. Near-infrared properties of bulges, discs and bars
We present data for a sample of 45 spiral galaxies over a range ofHubble types, imaged in the near-IR JK bands. Parameters are calculateddescribing the bulge, disc and bar K-band light distributions, and welook for correlations showing the interrelation between thesecomponents. We find that bulge profiles are not well-fitted by theclassic de Vaucouleurs profile, and that exponential or R^1/2 fits arepreferred. The bulge-to-disc ratio correlates only weakly with Hubbletype. Many of the galaxies show central reddening of their J-K colours,which we interpret as due to nuclear starbursts or dusty AGN. We definea new method for measuring the strength of bars, which we call`equivalent angle'. We stress that this is better than the traditionalbar-interbar contrast, as it is not subject to seeing and resolutioneffects. Bars are found in 40 of the 45 galaxies, nine of which had beenpreviously classified as unbarred. Bar strengths are found not tocorrelate with disc surface brightness or the presence of nearneighbours, but a tendency is found for the most strongly barredgalaxies to lie within a restricted, intermediate range of bulge-to-discratio. Bar light profiles are found to be either flat or exponentiallydecreasing along their long axes, with profile type not correlatingstrongly with Hubble type. Bar short axis profiles are significantlyasymmetric, with the steeper profile being generally on the leadingedge, assuming trailing arms. In the K band we find bars with higheraxial ratios than have been found previously in optical studies.
| 21 CM H1 Line Spectra of Galaxies in Nearby Clusters
A compilation of HI line fluxes, systemic velocities and line widths ispresented for \Ndet detected galaxies, mostly in the vicinities of 30nearby rich clusters out to a redshift of z ~ .04, specifically for usein applications of the Tully-Fisher distance method. New 21 cm HI lineprofiles have been obtained for ~ 500 galaxies in 27 Abell clustersvisible from Arecibo. Upper limits are also presented for \Nnod galaxiesfor which HI emission was not detected. In order to provide ahomogeneous line width determination optimized for Tully-Fisher studies,these new data are supplemented by the reanalysis of previouslypublished spectra obtained both at Arecibo and Green Bank that areavailable in a digital archive. Corrections for instrumental broadening,smoothing, signal-to-noise and profile shape are applied, and anestimate of the error on the width is given. When corrected forturbulent broadening and viewing angle, the corrected velocity widthspresented here will provide the appropriate line width parameter neededto derive distances via the Tully-Fisher relation.
| Large-Scale Structure at Low Galactic Latitude
We have extended the CfA Redshift Survey to low galactic latitudes toinvestigate the relation between the Great Wall in the North GalacticCap and the Perseus-Pisces chain in the South Galactic Cap. We presentredshifts for 2020 galaxies in the Catalogue of Galaxies and of Clustersof Galaxies (Zwicky et al. 1961-68, CGCG) in the following regions: 4^h^<= α <= 8^h^, 17^h^ <= α <= 20^h^, 0^deg^ <=δ <= 45^deg^. In these regions, the redshift catalogue includes1664 galaxies with B(0) <= 15.5 (of which 820 are newly measured) andis 97% complete. We also include redshifts for an additional 356galaxies in these regions with B(O) > 15.5; of these, 148 werepreviously unmeasured. The CGCG samples the galaxy distribution down tob_II_ = 10^deg^. In this paper, we discuss the acquisition and reductionof the spectra, and we examine the qualitative features of the redshiftdistribution. The Great Wall and the Perseus-Pisces chain are not simplyconnected across the Zone of Avoidance. These structures, which at firstappear to be coherent on scales of ~100 h^-1^ Mpc or more, actually formthe boundaries of neighboring voids of considerably smaller scale,approximately 50h^-1^ Mpc. The structures delineated by ouroptically-selected sample are qualitatively similar to those detected bythe far-infrared-selected IRAS 1.2 Jansky Survey (Fisher et al. 1995).Although the IRAS survey probes more deeply into the Zone of Avoidance,our optically-selected survey provides better sampling of structures atb_II_ >= 10^deg^.
| 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.
| Structure and Evolution of White Dwarfs
We review single white dwarf properties and describe how the study ofthe pulsations observed in them give us information on stellar structureand evolution.
| The Tully-Fisher relation of the IRAS minisurvey galaxies
We investigated the possible influence on the Tully-Fisher relation ofactive massive star formation in IRAS galaxies, in order to estimate thecontribution of star formation to their near-infrared luminosity. Weobserved 60 galaxies from the infrared complete so- called IRASMinisurvey sample in the 21 cm H1 line at Arecibo, determined thenear-infrared (H-band) Tully-Fisher relation for the 36 objects in thesample we judged to be usable for this purpose, and compared thisrelation with that of optically selected normal galaxies. The resultsshow no significant enhancement of the near- infrared luminosities ofthe IRAS Minisurvey galaxies compared to those of the optically selectednormal glaxies. From these results we inferred that in the minisurveygalaxies the average contribution of the active massive star formationto the total near-infrared luminosity is less and that exponential decaytimes for the starbursts occurring in the Minisurvey galaxies are of theorder of 10 Myr. The Tully-Fisher relation shows one exceptional galaxy(IRAS 03565+2139) with an about 25 times higher luminosity than averagefor its rotational velocity.
| Neutral hydrogen observations of galaxies in the Hercules supercluster. III. CGCG fields at the edge of the void.
The third installment of a HI redshift survey in the region of theHercules supercluster is presented. This part of the survey presents HIspectra of 84 galaxies selected from the UGC and CGCG which extends thepreviously begun survey of late-type spiral galaxies in that region.Measured HI parameters from the spectra are given. For about 20% of thesample, these parameters are compared to those measured previously byother workers.
| Scatter of SC galaxies on the Tully-Fisher diagram and a dark matter problem
A sample of 130 Sc galaxies with photometric I-band profiles, measuredby Freudling (1990), and with reliable data on the width of the H I lineis considered. As a distance indicator on the diagram, different globalparameters of the galaxies were tested. The use of any combinations ofoptical and radio parameters of galaxies does not decrease the spread ofestimates of galactic distances lower than a minimum value of 0.07-0.06.This limit is not significantly influenced by the galactic environmenteither. About three-fifths of the galaxies exhibit significantdeviations of their brightness profile with respect to a standard linearone. However, an amplitude and a sign of the deviation do not correlatewith a galaxy location on the TF diagram. This feature may be related tothe presence of a dark matter component in the galaxies. The mean ratioof the total mass to the I-luminosity is nearly the same (about 3 solarmasses/solar luminosity) both for giant and dwarf galaxies, but itdepends on their surface brightness.
| The peculiar velocity field in the Hercules region
The three-dimensional distribution of galaxies in the Hercules region isstudied, using the Tully-Fisher relation to search for deviations from asmooth Hubble flow. Magnitudes and inclinations are given for 86galaxies based on new I-band CCD images, and redshift-independentdistances are estimated and used to estimate peculiar velocities of thegalaxies. The gravitationally induced deviations from a smooth Hubbleflow is modeled using a sample of 2165 galaxies for which only redshiftsare known. A comparison of predicted velocities withredshift-independent distances indicates a value of 0.7 for the densityparameter Omega.
| The radio properties of galaxies with high far-infrared luminosities
Observations have been made with the Very Large Array, mainly at 5 GHz,of a sample of galaxies with high far-infrared luminosities selectedfrom the Infrared Astronomical Satellite (IRAS) minisurvey. The surfacebrightnesses of the minisurvey sources are greater than those of thedisks of normal galaxies but are similar to those of the central radiosources in these galaxies; the minisurvey sources, however, have muchlarger luminosities and physical sizes than these central sources. Onthe basis of the available data at all wavelengths, it is concluded thatthe far-infrared and radio emission from the minisurvey galaxies iscaused by star formation, not by active nuclei. It is found that thesize of the radio source is inversely correlated with the 60-100 microncolor temperature but is independent of the far-infrared luminosity.
| A further study of the relation of the radio-far-infrared in galaxies. I - Observations and data processing
The radio luminosities of 99 galaxies at 6.3 cm (and of 31 of them at2.8 cm) are determined on the basis of observations obtained with the100-m Effelsberg radio telescope during March-August 1984 and comparedto the IRAS color-corrected FIR luminosities, extending the survey of deJong et al. (1985). The data-reduction procedures are described, and theresults are presented in extensive tables and maps and brieflycharacterized. The correlation of radio to FIR luminosity is confirmedover about four decades in both parameters, and the dispersion of logP(6.3 cm)/L(FIR) is found to be about 0.2, which is significantlysmaller than the dispersion found by de Jong et al. The improvement isattributed to color correction, integration over the 100-60-micronrange, and the exclusion of ambiguous identifications.
| Near-infrared observations of IRAS minisurvey galaxies
Near-infrared photometry was obtained for 82 galaxies from the InfraredAstronomy Satellite (IRAS) minisurvey, a sample of infrared selectedgalaxies. The near-infrared colors of these galaxies are similar tothose of normal field spiral galaxies, but cover a larger range in J - Hand H - K. There is evidence of a tighter correlation between the nearand far infrared emission than exists between far-infrared and thevisible emission. These results suggest that hot dust emissioncontributes to the 2.2 micron luminosity, and extinction by dust affectsboth the near-infrared colors and the visible luminosities. In addition,there is an indication that the far-infrared emission in many of theminisurvey galaxies is coming from a strong nuclear component.
| Properties of IRAS galaxies with B(0)T not greater than approximately 14.5
The optical and infrared properties of 86 galaxies from IRAS circulars1-15, identified with optically bright galaxies in RC-2 and UGC havebeen studied. It is seen that B(0)T, the face-on integratedblue magnitude, is correlated with the far-infrared (FIR) flux. For asubsample of 61 galaxies for which distances are available, it is foundthat the color temperature of FIR emitting dust is correlated with theFIR luminosity, but not with the blue band luminosity. This along withthe observed ratio of L(FIR)/L(B) implies that the observed blueluminosity is unlikely to be associated with young star formationactivity. Associating FIR luminosity with young star formation activityin molecular clouds and the blue luminosity to the mass of the galaxy, avalue of 5-10 solar luminosity/solar mass is estimated for the meanratio of total FIR luminosity to the mass of the gas in these galaxies.
| CO emission from IRAS galaxies
The results of a search for CO emission in 20 galaxies in the IRAScirculars are presented. The observations were carried out using the14-m millimeter telescope of the Five College Radio AstronomyObservatory (FCRAO) at a half-power beam width of 45 arcsec. CO wasdetected in 10 of the galaxies, including Arp 220 and NGC 6240. A roughcorrelation was found between CO and 10-micron luminosities, although awide scatter was observed in the relation. The very luminous far-IRgalaxies Arp 220 and NGC 6240 contain 3 x 10 to the 10th solar mass ofH2, or a factor of 3 more molecular gas than was found in the luminousspiral galaxies NGC and M51. It is shown that if the far-IR emissionoriginated in a region much smaller than 45 arcsec, the surface densityof the molecular hydrogen in Arp 220 may exceed that observed in any Scgalaxy.
| Neutral hydrogen in isolated galaxies. IV - Results for the Arecibo sample
A standard sample for the comparison of the H I content of galaxies invarious intergalactic environments is presently defined by means ofobservations of 324 isolated galaxies lying in the declination rangeaccessible to the Arecibo 305-m telescope. Both mapping and single pointspectra are used to compute the integral properties of these galaxies.Neutral hydrogen was detected in 288 of the 324 galaxies surveyed, andit is noted that the optical diameter of a spiral disk is bettercorrelated with the hydrogen mass than the morphological type. When usedto define a measure of H I content, the isolated galaxy sample canpredict 'normalcy' with an accuracy that carries a standard error ofabout 0.20 in the log of the H I mass, if a dependence on disk size, aswell as type, is taken into account.
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