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The WSRT wide-field H I survey. I. The background galaxy sample
We have used the Westerbork array to carry out an unbiased wide-fieldsurvey for H I emission features, achieving an RMS sensitivity of about18 mJy/Beam at a velocity resolution of 17 km s-1 over 1800deg2 and between -1000 < VHel <+6500 kms-1. The primary data consists of auto-correlation spectrawith an effective angular resolution of 49' FWHM, althoughcross-correlation data were also acquired. The survey region is centeredapproximately on the position of Messier 31 and is Nyquist-sampled over60x 30o in RA x Dec. More than 100 distinct features aredetected at high significance in each of the two velocity regimes(negative and positive LGSR velocities). In this paper we present theresults for our H I detections of external galaxies at positive LGSRvelocity. We detect 155 external galaxies in excess of 8sigma inintegrated H I flux density. Plausible optical associations are foundwithin a 30' search radius for all but one of our H I detections in DSSimages, although several are not previously cataloged or do not havepublished red-shift determinations. Our detection without a DSSassociation is at low galactic latitude. Twenty-three of our objects aredetected in H I for the first time. We classify almost half of ourdetections as ``confused'', since one or more companions is catalogedwithin a radius of 30' and a velocity interval of 400 km s-1.We identify a handful of instances of significant positional offsetsexceeding 10 kpc of unconfused optical galaxies with the associated H Icentroid, possibly indicative of severe tidal distortions or uncatalogedgas-rich companions. A possible trend is found for an excess of detectedH I flux in unconfused galaxies within our large survey beam relative tothat detected previously in smaller telescope beams, both as function ofincreasing distance and increasing gas mass. This may be an indicationfor a diffuse gaseous component on 100 kpc scales in the environment ofmassive galaxies or a population of uncataloged low mass companions. Weuse our galaxy sample to estimate the H I mass function from our surveyvolume. Good agreement is found with the HIPASS BGC results, but onlyafter explicit correction for galaxy density variations with distance.Table 1 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/406/829 and Fig. 3 is onlyavailable in electronic form at http://www.edpsciences.org
| 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.
| 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.
| 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.
| A 21 CM survey of the Pisces-Perseus supercluster. III - The region north of +38 degrees
As part of a comprehensive survey of galaxies in the region of thePisces-Perseus supercluster and its surroundings, 21-cm lineobservations obtained with the NRAO 91-m telescope are presented for 383galaxies in the right ascension range from 22 to 10 hr and north of +38deg declination. Recent improvements to the Green Bank receiver/feedsystem have dramatically raised detection rates at the distance ofPisces-Perseus (cz = +5000 km/s). The present study has contributed todouble the number of known redshifts outside rich clusters in thissection of the sky. The H I content of the current sample, as expressedin terms of the H I mass expected for a galaxy of the same optical sizeand morphology, matches the standard of normalcy established forisolated galaxies.
| The space distribution of emission-line galaxies
The space distribution of emission-line galaxies in three 4 x 4 degfields of the Second Byurakan Survey is investigated, using mainlyspectra taken with the 6-m telescope. Two fields, centered at 8h00m, +59 deg and 9h50m, + 55 deg, show regions of enhanced galaxy densityseparated by a 50-Mpc void and evidently comprising several groups orclusters of galaxies. In the third field (11h30m, + 59 deg) the objectsare distributed continuously out ot R = 300 Mpc.
| Observations of galaxies with an ultraviolet continuum at a frequency of 102 MHz. II
A radio survey was carried out at 102 MHz to study the UV continuum of67 galaxies. The objects included 58 Seyfert galaxies and two BL Lacobjects. Data on the total flux, the flux of the scintillatingcomponent, the angular diameter of the scintillating component, thesolar elongation and the type of the galaxy are provided for the 11sources of 102 MHz emission detected. Radio spectra are also tabulatedin terms of the scintillating, central, northern, southern and easternradio components for the galaxies NGC 1068, 4151 and 5548. Variousdetails observed in the galaxies which featured 102 MHz emissions arebriefly discussed.
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