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|The Westerbork HI survey of spiral and irregular galaxies. III. HI observations of early-type disk galaxies|
We present Hi observations of 68 early-type disk galaxies from the WHISPsurvey. They have morphological types between S0 and Sab and absoluteB-band magnitudes between -14 and -22. These galaxies form the massive,high surface-brightness extreme of the disk galaxy population, few ofwhich have been imaged in Hi before. The Hi properties of the galaxiesin our sample span a large range; the average values of MHI/LB and DH I/D25 are comparableto the ones found in later-type spirals, but the dispersions around themean are larger. No significant differences are found between the S0/S0aand the Sa/Sab galaxies. Our early-type disk galaxies follow the same Himass-diameter relation as later-type spiral galaxies, but theireffective Hi surface densities are slightly lower than those found inlater-type systems. In some galaxies, distinct rings of Hi emissioncoincide with regions of enhanced star formation, even though theaverage gas densities are far below the threshold of star formationderived by Kennicutt (1989, ApJ, 344, 685). Apparently, additionalmechanisms, as yet unknown, regulate star formation at low surfacedensities. Many of the galaxies in our sample have lopsided gasmorphologies; in most cases this can be linked to recent or ongoinginteractions or merger events. Asymmetries are rare in quiescentgalaxies. Kinematic lopsidedness is rare, both in interacting andisolated systems. In the appendix, we present an atlas of the Hiobservations: for all galaxies we show Hi surface density maps, globalprofiles, velocity fields and radial surface density profiles.
|On the alignment between binary spiral galaxies|
We show some significance against the null hypothesis of randominteractions of binary spiral galaxies, and in favour of the alternativethat more interactions than expected occur for axes either nearlyparallel (spins being parallel or anti-parallel) or nearly orthogonal.We discuss this in the context of similar prior studies, using adifferent statistical focus in such a way that we are able toincorporate additional data.
|A Study of the Distribution of Star-forming Regions in Luminous Infrared Galaxies by Means of Hα Imaging Observations|
We performed Hα imaging observations of 22 luminous infraredgalaxies to investigate how the distribution of star-forming regions inthese galaxies is related to galaxy interactions. Based on correlationdiagrams between Hα flux and continuum emission for individualgalaxies, a sequence for the distribution of star-forming regions wasfound: very compact (~100 pc) nuclear starbursts with almost nostar-forming activity in the outer regions (type 1), dominant nuclearstarbursts <~1 kpc in size with a negligible contribution from theouter regions (type 2), nuclear starbursts >~1 kpc in size with asignificant contribution from the outer regions (type 3), and extendedstarbursts with relatively faint nuclei (type 4). These classes ofstar-forming regions were found to be strongly related to globalstar-forming properties, such as star formation efficiency, far-infraredcolor, and dust extinction. There was a clear tendency for the objectswith more compact distributions of star-forming regions to show a higherstar formation efficiency and hotter far-infrared color. An appreciablefraction of the sample objects were dominated by extended starbursts(type 4), which is unexpected in the standard scenario ofinteraction-induced starburst galaxies. We also found that thedistribution of star-forming regions was weakly but clearly related togalaxy morphology: severely disturbed objects had a more concentrateddistribution of star-forming regions. This suggests that the propertiesof galaxy interactions, such as dynamical phase and orbital parameters,play a more important role than the internal properties of progenitorgalaxies, such as dynamical structure or gas mass fraction. We alsodiscuss the evolution of the distribution of star-forming regions ininteracting galaxies.
|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.
|The Arizona-New Mexico Spectroscopic Survey of Galaxies. I. Data for the Western End of the Perseus Supercluster|
We present new optical spectroscopic data for 347 galaxies in the regionof the Perseus supercluster. The new data were obtained using theSteward Observatory 2.3 m telescope and cover the whole optical window.Included are redshifts (for 345 objects), absorption-line equivalentwidths, a continuum index measuring the 4000 Å break, andemission-line flux ratios. After 11 objects are rejected for being toofaint and redshifts for 26 objects are added from the literature, wearrive at a complete sample of 361 galaxies. The distribution ofredshifts for the whole sample is examined, and we show the relationshipof the continuum index to morphology.
|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 I-Band Tully-Fisher Relation for SC Galaxies: 21 Centimeter H I Line Data|
A compilation of 21 cm line spectral parameters specifically designedfor application of the Tully-Fisher (TF) distance method is presentedfor 1201 spiral galaxies, primarily field Sc galaxies, for which opticalI-band photometric imaging is also available. New H I line spectra havebeen obtained for 881 galaxies. For an additional 320 galaxies, spectraavailable in a digital archive have been reexamined to allow applicationof a single algorithm for the derivation of the TF velocity widthparameter. A velocity width algorithm is used that provides a robustmeasurement of rotational velocity and permits an estimate of the erroron that width taking into account the effects of instrumental broadeningand signal-to-noise. The digital data are used to establish regressionrelations between measurements of velocity widths using other commonprescriptions so that comparable widths can be derived throughconversion of values published in the literature. The uniform H I linewidths presented here provide the rotational velocity measurement to beused in deriving peculiar velocities via the TF method.
|The I-Band Tully-Fisher Relation for SC Galaxies: Optical Imaging Data|
Properties derived from the analysis of photometric I-band imagingobservations are presented for 1727 inclined spiral galaxies, mostly oftypes Sbc and Sc. The reduction, parameter extraction, and errorestimation procedures are discussed in detail. The asymptotic behaviorof the magnitude curve of growth and the radial variation in ellipticityand position angle are used in combination with the linearity of thesurface brightness falloff to fit the disk portion of the profile. TotalI-band magnitudes are calculated by extrapolating the detected surfacebrightness profile to a radius of eight disk scale lengths. Errors inthe magnitudes, typically ~0.04 mag, are dominated by uncertainties inthe sky subtraction and disk-fitting procedures. Comparison is made withthe similar imaging database of Mathewson, Ford, & Buchhorn, both aspresented originally by those authors and after reanalyzing theirdigital reduction files using identical disk-fitting procedures. Directcomparison is made of profile details for 292 galaxies observed incommon. Although some differences occur, good agreement is found,proving that the two data sets can be used in combination with onlyminor accommodation of those differences. The compilation of opticalproperties presented here is optimized for use in applications of theTully-Fisher relation as a secondary distance indicator in studies ofthe local peculiar velocity field.
|Structure and kinematics of the peculiar galaxy NGC 128|
This is a multiband photometric and spectroscopic study of the peculiarS0 galaxy NGC 128. We present results from broad (Band R) and narrow (Hα ) band optical CCD photometry, near (NIR)and far (FIR) infrared observations, long slit spectroscopy, andFabry-Perot interferometry (CIGALE). The peculiar peanut shapemorphology of the galaxy is observed both at optical and near-infraredwavelengths. The stellar disk is thick and distorted (arc-bended), witha color asymmetry along the major axis due to the presence of a largeamount of dust, estimated through NIR and FIR data of ~ 6\ 10(6\)M_ȯ, in the region of interaction with the companion galaxyNGC 127. The color maps are nearly uniform over thewhole galaxy, but for the major axis asymmetry, and a small gradienttoward the center indicating the presence of a redder disk-likecomponent. The Hα image indeed reveals the existence of a tiltedgaseous ``disk'' around the center, oriented with the major axis towardthe companion galaxy NGC 127. Long slit and CIGALE data confirm thepresence of gas in a disk-like component counter-rotating and inclinedapproximately of 50(deg) to the line of sight. The mass of the gas diskin the inner region is ~ 2.7\ 10(4) \ M_ȯ. The stellar velocityfield is cylindrical up to the last measured points of the derivedrotation curves, while the velocity dispersion profiles are typical foran S0 galaxy, but for an extended constant behaviour along the minoraxis. Based on observations taken at ESO La Silla and at the SpecialAstrophysical Observatory (SAO) of the Russian Academy of Sciences(RAS).
|Very Wide Galaxy Pairs of the Northern and Southern Sky|
We present highly accurate observations of the 21 cm line of hydrogen ingalaxies made at the Arecibo and Parkes Observatories. The galaxiesobserved have been identified, through rigorous selection criteriaapplied to the CfA and SSRS catalogs, as being members of pairs withprojected separations of up to 1.5 Mpc (H0 = 75 km s-1 Mpc-1). Theseobservations form the completion of the Chengalur-Nordgren galaxy pairsample with data previously published by Chengalur, Nordgren andcolleagues. The new selection criteria used in this paper are anextension to larger projected separations of the criteria usedpreviously. Forty-nine new galaxies are observed, while H I is detectedin 41 of them. With the addition of these galaxies, the completed samplehas highly accurate H I velocities for a total of 219 galaxies.
|Groups of galaxies. III. Some empirical characteristics.|
|Catalogue of HI maps of galaxies. I.|
A catalogue is presented of galaxies having large-scale observations inthe HI line. This catalogue collects from the literature the informationthat characterizes the observations in the 21-cm line and the way thatthese data were presented by means of maps, graphics and tables, forshowing the distribution and kinematics of the gas. It containsfurthermore a measure of the HI extension that is detected at the levelof the maximum sensitivity reached in the observations. This catalogueis intended as a guide for references on the HI maps published in theliterature from 1953 to 1995 and is the basis for the analysis of thedata presented in Paper II. The catalogue is only available inelectronic form at the CDS via anonymous ftp 184.108.40.206 orhttp://cdsweb.u-strasbg.fr/Abstract.html
|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.
|Recalibration of the H-0.5 magnitudes of spiral galaxies|
The H-magnitude aperture data published by the Aaronson et al.collaboration over a 10 year period is collected into a homogeneous dataset of 1731 observations of 665 galaxies. Ninety-six percent of thesegalaxies have isophotal diameters and axial ratios determined by theThird Reference Cataloque of Bright Galaxies (RC3; de Vaucouleurs et al.1991), the most self-consistent set of optical data currently available.The precepts governing the optical data in the RC3 are systematicallydifferent from those of the Second Reference Catalogue (de Vaucouleurs,de Vaucouleurs, & Corwin 1976), which were used by Aaronson et al.for their original analyses of galaxy peculiar motions. This in turnleads to systematic differences in growth curves and fiducialH-magnitudes, prompting the present recalibration of the near-infraredTully-Fisher relationship. New optically normalized H-magnitude growthcurves are defined for galaxies of types SO to Im, from which new valuesof fiducial H-magnitudes, Hg-0.5, are measured forthe 665 galaxies. A series of internal tests show that these fourstandard growth curves are defined to an accuracy of 0.05 mag over theinterval -1.5 less than or equal to log (A/Dg) less than orequal to -0.2. Comparisons with the Aaronson et al. values of diameters,axial ratios, and fiducial H-magnitudes show the expected differences,given the different definitions of these parameters. The values ofHg-0.5 are assigned quality indices: a qualityvalue of 1 indicates an accuracy of less than 0.2 mag, quality 2indicates an accuracy of 0.2-0.35 mag, and quality 3 indicates anaccuracy of more than 0.35 mag. Revised values of corrected H I velocitywidths are also given, based on the new set of axial ratios defiend bythe RC3.
|The spatial distribution, kinematics, and dynamics of the galaxies in the region of Abell 2634 and 2666|
A total of 663 galaxies with known redshifts in a 12 deg x 12 deg fieldcentered on A2634, including 211 new measurements, are used to study indetail the structure of the region. In it we find six main galaxyconcentrations: the nearby clusters A2634 and A2666, two groups in thevicinity of A2634, and two distant clusters at approximately 18,000(A2622) and approximately 37,000 km/s seen in projection near the coreof A2634. For A2634, the most richly sampled of those concentrations, weare able to apply strict cluster membership criteria. Two samples - onecontaining 200 galaxies within 2 deg from the cluster center and asecond, magnitude-limited, of 118 galaxies within the central halfdegree - are used to examine the structure, kinematics, dynamics, andmorphological segregation of the cluster. We show that early typegalaxies appear to be a relaxed system, while the spiral populationeschews the center of the cluster and exhibits both a multimodalvelocity distribution and a much larger velocity dispersion that theellipticals. We propose that the spiral galaxies of A2634 represent adynamically young cluster population. For the galaxy component of A2634,we find no evidence of significant substructure in the central regions.We also conclude that the adoption of lenient membership criteria thatignore the dynamical complexity of A2634 are unlikely to be responsiblefor the conflicting results reported on the motion of this cluster withrespect ot the CMB. The kinematical and dynamical analysis is extendedto A2634's close companion, A2666, and the two distant backgroundclusters.
|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.
|H I observations of binary spiral galaxies|
A sample of binary spiral galaxies has been observed with the Areciboand Westerbork radio telescopes in the H I 21 cm line, and these data,in conjunction with optical information, are used to ascertain thespin-vector spatial orientation of the galaxies, as well as to estimatetheir systemic and rotation velocities. A tabulation is given of theresults thus obtained for 23 galaxies.
|Peculiar motions in superclusters: Perseus--Pisces|
We discuss the near infrared observations obtained for a set of 81galaxies in the region of the Perseus--Pisces supercluster. From these,in conjunction with the 21 cm data of the Arecibo sample, we estimatethe peculiar velocities via the Tully-Fisher relation and the model ofthe local perturbations as derived by Han and Mould. From the datadiscussed we find that the supercluster main structure is shrinking. Toexplain the size and velocities observed the model requires, for thesupercluster, a mean overdensity of about delta rho/rho = 9 whichcorresponds to a total mass of 1016 solar masses to cover anextension of about 100 Mpc.
|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.
|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.
|KISO survey for ultraviolet-excess galaxies. XIV.|
The 14th list and identification charts of the UV-excess galaxiesdetected on the multicolor plates taken with the Kiso Schmidt telescopefor 10 survey fields are presented. In the sky area of some 300 sq deg,about 470 objects are cataloged down to the photographic magnitude ofabout 17.5.
|Quantization of redshift differences in isolated galaxy pairs|
Improved 21 cm data on isolated galaxy pairs are presented whicheliminate questions of inhomogeneity in the data on such pairs andreduce observational error to below 5 km/s. Quantization is sharpened,and the 'zero' peak is shown to be displaced from zero to a locationnear 24 km/s. An exclusion principle is suggested whereby identicalredshifts are forbidden in limited volumes. The radio data and data fromSchweizer (1987) are combined with the best optical data on closeKarachentsev pairs to provide a cumulative sample of 84 of the bestdifferentials now available. New 21 cm observations are used to test forthe presence of small differentials in very wide pairs, and thedeficiency near zero is found to continue to very wide spacings. A lossof wide pairs by selection bias cannot produce the observed zerodeficiency. A new test using pairs selected from the Fisher-Tullycatalog is used to demonstrate quantization properties of thirdcomponents associated with possible pairs.
|Central Parts of Some Irregular Type-II Candidate Galaxies|
|Cosmology from a galaxy group catalog. I - Binaries|
A new, completely objective group-finding algorithm is described andapplied to the CfA redshift catalog. The binary galaxies are isolatedfor analysis. The assumptions underlying the analysis are (1) that lighttraces mass, (2) that our binary galaxy subsets are representative lighttracers, and (3) that the binary orbits are circular. The primary resultof the work is that the resulting bias-free binary catalogs are afunction of the assumed cosmological model. For virtually any inputvalue of Omega(0) in the range 0.01-5.00, there is a reasonablyconsistent interpretation of the CfA survey such that the specifiedvalue of Omega(0) can be derived from the binary sample obtained underthat interpretation. A secondary result is that the higher the inputvalue of Omega(0), the broader the intrinsic distribution in M/L, andhence the less valid the assumption that light traces mass.
|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.
|Neutral hydrogen in small groups of galaxies|
Neutral hydrogen in 36 pairs and small groups of galaxies was studiedusing the Arecibo radio telescope. Potential groups were selected fromthe Uppsala General Catalogue of Galaxies of Nilson (1973) by a simplealgorithm with the aims of determining or improving redshifts forgalaxies in possible groups and of mapping some of the larger galaxiesto determine their internal dynamics. The H I spectra are examined indetail and problems of confusion in these and previous observations areaddressed. A simple analysis of the groups' mean dynamical mass suggeststhat the mass determined from the galaxies' rotation is sufficient tobind them, but there may be important unmodeled selection orcontamination problems. A simple method for estimating errors of H Ivelocity measurements is also derived.
|A 21 CM survey of the Pisces-Perseus supercluster. II - The declination zone +21.5 to +27.5 degrees|
Neutral-hydrogen 21-cm line spectra and derived parameters are presentedfor a sample of spiral galaxies in the region bounded by an R.A. greaterthan 22 h and less then 0.04 h, and a declination greater than +21 deg30 min and less than +27 deg 30 min, covering the Zwicky fields 470 to488, as the second installment of a survey of the region of thePisces-Perseus supercluster. New H I line observations made with theArecibo 305 m telescope detected 275 galaxies of 318 studied. Atabulation of derived galaxian properties is given. The redshiftdistribution shows gross departures from that expected for a sample withsimilar magnitude characteristics but homogeneously located in space.These new data will be incorporated into the overall survey of thethree-dimensional structure in the Pisces-Perseus region.
|Analysis of groups of galaxies with accurate redshifts|
Arecibo radio telescope redshift measurements have been obtained forover 100 galaxies in more than 40 different groups which generallyconsist of a large spiral galaxy with one or more companions. This setof data is supplemented with over 160 galaxies in more than 40 groupswhose dominant galaxy is brighter than 11.8 mag. An analysis of theentire sample indicates that typical structure in extragalactic space isone in which a large central galaxy has smaller and fainter companionsextending from about 20-900 kpc around. The companion galaxies in thesegroups have significantly higher redshifts than the brightest galaxy inthe group, confirming previous studies in whose results the companiongalaxies are systematically redshifted with respect to the dominantgalaxy.
|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.
|Enhanced radio emission in binary spiral galaxies|
A comparison is conducted between the radio emission characteristics ofa sample of isolated pairs of spiral galaxies and those of a sample ofisolated spiral galaxies for which complete distance information isavailable. It is noted that double galaxy total emission is, on average,a factor of 2 more powerful than that of isolated spiral galaxies ofcomparable luminosity. The radio emission enhancement in these doublegalaxies is correlated with a tidal index, in keeping with a tidalorigin for the enhancement.
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