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A catalog of edge-on disk galaxies. From galaxies with a bulge to superthin galaxies
Spiral galaxies range from bulge-dominated early-type galaxies to latetypes with little or no bulge. Cosmological models do not predict theformation of disk-dominated, essentially bulgeless galaxies, yet theseobjects exist. A particularly striking and poorly understood example ofbulgeless galaxies are flat or superthin galaxies with large axisratios. We therefore embarked on a study aimed at a better understandingof these enigmatic objects, starting by compiling a statisticallymeaningful sample with well-defined properties. The disk axis ratios canbe most easily measured when galaxies are seen edge-on. We used datafrom the Sloan Digital Sky Survey (SDSS) in order to identify edge-ongalaxies with disks in a uniform, reproducible, automated fashion. Inthe five-color photometric database of the SDSS Data Release 1 (2099deg^2) we identified 3169 edge-on disk galaxies, which we subdividedinto disk galaxies with bulge, intermediate types, and simple diskgalaxies without any obvious bulge component. We subdivided these typesfurther into subclasses: Sa(f), Sb(f), Sc(f), Scd(f), Sd(f), Irr(f),where the (f) indicates that these galaxies are seen edge-on. Here wepresent our selection algorithm and the resulting catalogs of the 3169edge-on disk galaxies including the photometric, morphological, andstructural parameters of our targets. A number of incompleteness effectsaffect our catalog, but it contains almost a factor of four morebulgeless galaxies with prominent simple disks (flat galaxies) withinthe area covered here than previous optical catalogs, which were basedon the visual selection from photographic plates (cf. Karachentsev etal. 1999, Bull. Special Astrophys. Obs., 47, 5). We find thatapproximately 15% of the edge-on disk galaxies in our catalog are flatgalaxies, demonstrating that these galaxies are fairly common,especially among intermediate-mass star-forming galaxies. Bulgelessdisks account for roughly one third of our galaxies when also puffydisks and edge-on irregulars are included. Our catalog provides auniform database for a multitude of follow-up studies of bulgelessgalaxies in order to constrain their intrinsic and environmentalproperties and their evolutionary status.
| The 2MASS-selected Flat Galaxy Catalog
An all-sky catalog of 18020 disc-like galaxies is presented. Thegalaxies are selected from the Extended Source Catalog of the Two MicronAll-Sky Survey (XSC 2MASS) basing on their 2MASS axial ratio a/b ≥ 3.The Catalog contains data on magnitudes of a galaxy in the J, H,KS bands, its axial ratio, positional angle, index ofluminosity concentration, as well as identification of the galaxy withthe LEDA and the NED databases. Unlike the available optical catalogs,the new 2MFGC catalog seems to be more suitable to study cosmicstreaming on a scale of z <~ 0.1. The dipole moment of distributionof the bright (K < 11m) 2MFGC objects (l = 227°, b =41° or SGL = 90°, SGB = -43°) lies within statistical errors(±15°) in the direction of the IRAS dipole and the opticalRFGC dipole.
| 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.
| 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.
| Optical positions and 327 MHz flux-densities of UGC galaxies in selected Westerbork fields
The study presents accurate optical positions of 421 UGC galaxies whichare used to search for 30 92-cm WSRT fields observed for emission fromthese galaxies. Good 92-cm flux densities were obtained for 140galaxies, marginal flux densities for 71 galaxies, and upper limits for210 galaxies. For 35 galaxies, spectral indices in the decimeterwavelength range are determined. The mean spectral index for spiralgalaxies (0.72 +/- 0.03) is very similar to that of elliptical galaxies(0.64 +/- 0.10). The four multiple systems in the sample have a muchflatter spectral index (-0.21 +/- 0.07), from which the presence of asignificant thermal component in their total radio emission issuggested. Comparison with IRAS results show that about half of thegalaxies detected at radio wavelengths are detected in the FIR. It isproposed that some spiral galaxies are anomalously weak in the IR ascompared with their radio brightness.
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