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Color functions of stellar systems
Model calculations of the photometric evolution of rather dense stellarsystems, such as globular clusters, are presented. On“luminosity-effective temperature” diagrams of thesesystems, low-mass stars are concentrated near the minimum and maximumtemperatures for a given luminosity and are deficient in theintermediate region. This sort of double-peaked distribution of thestars can be avoided in open models with ejection of excess metals intothe surrounding medium. The distributions of the stars with respect toeffective temperature on a “ luminosity-effectivetemperature” diagram are sensitive to the history of starformation in the system and to possible time variations in the initialmass function. In open systems with a single-peak distribution function,the asymmetry in the distribution varies over wide limits with the lowerbound for the initial mass function and this can be used to establishwhether the first generations of stars might have been more massive thanin the present epoch.
| 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.
| A Comprehensive Spectral and Variability Study of Narrow-Line Seyfert 1 Galaxies Observed by ASCA. I. Observations and Time Series Analysis
I present a comprehensive and uniform analysis of 25 ASCA observationsfrom 23 narrow-line Seyfert 1 galaxies. The time series analysis ispresented in this paper, Part 1, and the spectral analysis andcorrelations are presented in the companion paper, Part 2. Time seriesanalysis shows that the excess variance from the NLS1 light curves isinversely correlated with their X-ray luminosity. However, with alogarithmic slope of ~-0.3, the dependence of the excess variance onluminosity is flat compared with broad-line objects and the expectedvalue of -1 from simple models. At a particular X-ray luminosity, theexcess variance is typically an order of magnitude larger for NLS1s thanfor Seyfert 1 with broad optical lines. There is, however, a largescatter, and a few objects show an even larger excess variance. Theexcess variance can be interpreted as a timescale if the shape of thevariability power spectrum, the length of the observation, and thewindow function are the same for all observations, and the properties ofthe sample objects are shown to be roughly consistent with thisrequirement. In particular, no strong evidence for changes during anobservation in the shape or normalization of the power spectrum wasfound once the systematic errors due to the 1/f nature of the powerspectrum was accounted for properly. Some of the more variable lightcurves are shown to be inconsistent with a linear, Gaussian process,implying that the process is non-Gaussian. It is possible that theprocess is nonlinear, but while the distinction between thesepossibilities is very important for differentiating between models, sucha distinction cannot be made using these data. The enhanced excessvariance exhibited by NLS1s can be interpreted as evidence that they arescaled-down versions of broad-line objects, having black hole massesroughly an order of magnitude smaller and requiring an accretion rate anorder of magnitude higher. Alternatively, NLS1s may exhibit aninherently different type of variability, characterized byhigh-amplitude flares, in which case a smaller black hole mass would notbe required.
| Near-infrared observations of galaxies in Pisces-Perseus. I. vec H-band surface photometry of 174 spiral
We present near-infrared, H-band (1.65 $() μm), surface photometry of174 spiral galaxies in the area of the Pisces-Perseus supercluster. Theimages, acquired with the ARNICA camera mounted on various telescopes,are used to derive radial profiles of surface brightness, ellipticities,and position angles, together with global parameters such as H-bandmagnitudes and diameters Radial profiles in tabular form and images FITSfiles are also available upon request from gmorio@arcetri.astro.it.}.The mean relation between H-band isophotal diameter D_{21.5} and theB-band D25 implies a B-H color of the outer disk bluer than3.5; moreover, D_{21.5}/D25 depends on (global) color andabsolute luminosity. The correlations among the various photometricparameters suggest a ratio between isophotal radius D_{21.5}/2 and diskscale length of ~ m3.5 and a mean disk central brightness ~ meq 17.5H-mag arcsec^{-2}. We confirm the trend of the concentration indexC31$ with absolute luminosity and, to a lesser degree, withmorphological type. We also assess the influence of non-axisymmetricstructures on the radial profiles and on the derived parameters. Basedon observations at the TIRGO, NOT, and VATT telescopes. TIRGO(Gornergrat, CH) is operated by CAISMI-CNR, Arcetri, Firenze. NOT (LaPalma, Canary Islands) is operated by NOTSA, the Nordic ObservatoryScientific Association. VATT (Mt. Graham, Az) is operated by VORG, theVatican Observatory Research Group Table 3 and Fig. 4 are only availablein electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html.
| Extensive Spiral Structure and Corotation Resonance
Spiral density wave theories demand that grand-design spiral structurebe bounded, at most, between the inner and outer Lindblad resonances ofthe spiral pattern. The corotation resonance lies between the outer andthe inner Lindblad resonances. The locations of the resonances are atradii whose ratios to each other are rather independent of the shape ofthe rotation curve. The measured ratio of outer to inner extent ofspiral structure for a given spiral galaxy can be compared to thestandard ratio of corotation to inner Lindblad resonance radius. In thecase that the measured ratio far exceeds the standard ratio, it islikely that the corotation resonance is within the bright optical disk.Studying such galaxies can teach us how the action of resonances sculptsthe appearance of spiral disks. This paper reports observations of 140disk galaxies, leading to resonance ratio tests for 109 qualified spiralgalaxies. It lists candidates that have a good chance of having thecorotation resonance radius within the bright optical disk.
| Kinematics of the local universe. VII. New 21-cm line measurements of 2112 galaxies
This paper presents 2112 new 21-cm neutral hydrogen line measurementscarried out with the meridian transit Nan\c cay radiotelescope. Amongthese data we give also 213 new radial velocities which complement thoselisted in three previous papers of this series. These new measurements,together with the HI data collected in LEDA, put to 6 700 the number ofgalaxies with 21-cm line width, radial velocity, and apparent diameterin the so-called KLUN sample. Figure 5 and Appendices A and B forcorresponding comments are available in electronic form at thehttp://www.edpsciences.com
| A Minnesota Automated Plate Scanner Catalog of Galaxies behind the Virgo Cluster and toward Its Antipode
We present a catalog of 1268 galaxies, essentially complete to B <=17.0, found by scanning glass copies of several fields of the originalPalomar Sky Survey using the Minnesota Automated Plate Scanner in itsisodensitometric mode (as opposed to the threshold densitometric modeused in the APS Catalog of the POSS I). In addition to the differentscanning mode, we have employed a different star-galaxy separationmethod and have visually inspected POSS prints to verify that each imageremaining in the catalog is nonstellar. The scanned fields aredistributed generally in two areas, one around the outskirts of theVirgo Cluster, the other toward the antipode of the cluster (but stillin the northern celestial hemisphere). The catalog gives the position ofthe center of each galaxy; estimates of the blue and red magnitudeswithin the outermost threshold crossing and of the blue magnitudeextrapolated to zero surface brightness; and the blue and red diametersof four ellipses fitted to the four threshold crossings (approximately23.8,23.6,23.2, and 22.7 mag arcsec 2 in blue, and 22.5,22.4,21.5, and21.2 mag arcsec^-2^ in red), and the ellipticities of those fourellipses. The catalog has served as a base from which to draw targetsfor a Tully-Fisher study of the Virgocentric infall velocity of theLocal Group.
| 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.
| Lower metallicity of the Galactic globular cluster system: Calcium triplet spectroscopy of metal-poor globular cluster giants
Medium-resolution spectra at the Ca II infrared triplet are presentedfor 164 giants in 12 metal-poor Galactic globular clusters. The data for4 for these clusters are combined with published data for 7 otherclusters with well-known metal abundances and used to calibrate thederivation of metallicity values for the remaining clusters from thesummed strength of the 2 strongest Ca lines at a given V -VHB. The mean (Fe/H) values we find are: -1.82 for NGC 2298,-2.10 for NGC 4372, -1.84 for NGC 4833, -2.10 for NGC 5053, -1.87 forNGC 5694, -1.94 for NGC 5897, -1.86 for NGC 6101 and -1.86 for NGC 6144,with a typical mean error of 0.05 dex from an average of 10 membergiants per cluster. Upper limits to any intrinsic intraclustermetallicity dispersion are less than or = 0.05 dex in all of theclusters except approximately 0.15 dex in NGC 5053 and NGC 5694, wherethe higher limits are due to the lower quality spectra for these moredistant clusters. The mean metallicity values for most of the programclusters are in excellent agreement with the Zinn scale, while those forNGC 5897 and NGC 5053 are 0.26 dex lower and 0.48 dex higher than givenby Zinn, respectively. The value for NGC 5897 is intermediate to thatgiven by the Washington photometry of Geisler et al. (1992b) and Zinn.The high value for NGC 5053 increases the already very significantdifference between the metallicity distribution functions of haloclusters and field stars. Our results, combined with previousdeterminations for other clusters, indicate that the lower metallicitylimit for globular clusters in the Galaxy is -2.25 +/- 0.10. A similarvalue also appears to hold for other nearby globular cluster systems. Wealso derive mean cluster radial velocities to a typical precision of 1.2km/s (mean error). The values for several of the program clusters aresignificantly different from previously published values. An updatedanalysis slightly strengthens van den Bergh's (1993) finding that haloclusters on retrograde orbits have different horizontal branchmorphologies than clusters on prograde orbits.
| The far-infrared properties of the CfA galaxy sample. I - The catalog
IRAS flux densities are presented for all galaxies in the Center forAstrophysics magnitude-limited sample (mB not greater than 14.5)detected in the IRAS Faint Source Survey (FSS), a total of 1544galaxies. The detection rate in the FSS is slightly larger than in thePSC for the long-wavelength 60- and 100-micron bands, but improves by afactor of about 3 or more for the short wavelength 12- and 25-micronbands. This optically selected sample consists of galaxies which are, onaverage, much less IR-active than galaxies in IR-selected samples. Itpossesses accurate and complete redshift, morphological, and magnitudeinformation, along with observations at other wavelengths.
| A 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.
| Arm classifications for spiral galaxies
The spiral arm classes of 762 galaxies are tabulated; 636 galaxies withlow inclinations and radii larger than 1 arcmin were classified on thebasis of their blue images on the Palomar Observatory Sky Survey (POSS),76 SA galaxies in the group catalog of Geller and Huchra were alsoclassified from the POSS, and 253 galaxies in high-resolution atlaseswere classified from their atlas photographs. This spiral armclassification system was previously shown to correlate with thepresence of density waves, and galaxies with such waves were shown tooccur primarily in the densest galactic groups. The present sampleindicates, in addition, that grand design galaxies (i.e., those whichtend to contain prominent density wave modes) are physically larger thanflocculent galaxies (which do not contain such prominent modes) by afactor of about 1.5. A larger group sample confirms the previous resultthat grand design galaxies are preferentially in dense groups.
| Isolated galaxies
A new list of isolated galaxies has been compiled in order to determinewhether or not a true isolated sample can be selected. The sampleselection and the statistical characteristics of the sample arediscussed. In agreement with previous findings, it is concluded that anunclustered background seems to be observationally and operationallymeaningless, and that clustering dominates in all regions of space.
| Nitrogen and oxygen evolution in dwarf irregular galaxies
In the present computation of numerical chemical evolution models for asample of 40 dwarf irregular galaxies, assuming bursts of star formationand taking account of galactic winds, N and O evolution is followed upin light of the most recent results on stellar evolution. The N and Oabundances observed are well reproduced by theoretical models with suchimplications as the ability to explain the N/O vs O diagrams of dwarfirregulars, as well as those of halo stars in the Galaxy, by means of aprimary fraction of N ranging from 30 to 50 percent. A Salpeter (1955)initial mass function is applicable to all these galaxies, whilefunctions strongly varying with metallicity do not yield the observeddata.
| Morphology of spiral galaxies. I - General properties
Red Palomar Sky Survey plates are scanned to characterize a completesample of 605 spiral galaxies north of declination -33 deg havinginclination angle less than 56 deg and blue diameter 2-15 arcmin. Theselection of the data and the reduction and parameter-extractionprocedures are explained, and the data and the results of statisticalanalysis are presented in tables and graphs. Findings reported include alow frequency of occurrence for small inclination angles (suggestingdistortion of outer structures), similar distributions of central diskbrightness for types Sa-Sc but not for types Sd-Sm (where mean valuesare smaller), fewer late-type galaxies with large exponential-disk scalelengths, no galaxies with both high central brightness and large scalelength (indicating a limit on angular momentum in galaxy formation), anda correlation between mean surface brightness and absolute magnitude forlater-type galaxies but not for types Sa-Scd.
| Very large spiral galaxies
As a first step in the systematic study of large spirals, which may beuseful in cosmological tests and studies of galaxy evolution, a catalogof the 107 largest known spiral galaxies is presented. Catalog galaxieshave isophotal diameters greater than 90 kpc, assuming an H(zero) valueof 50 km/sec per Mpc. UBVR photoelectric photometry is presented for 20of these galaxies, and absolute magnitudes are derived for all galaxiesin the catalog by transforming Zwicky magnitudes to the B(T) system.
| A survey of galaxy redshifts. IV - The data
The complete list of the best available radial velocities for the 2401galaxies in the merged Zwicky-Nilson catalog brighter than 14.5mz and with b (II) above +40 deg or below -30 deg ispresented. Almost 60 percent of the redshifts are from the CfA surveyand are accurate to typically 35 km/s.
| Index of galaxy spectra.
Not Available
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