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|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.
|On the relationship between radio emission and optical properties in early-type galaxies|
To study the origin of radio activity in early-type galaxies, thepossible dependence of their radio emission on basic optical parameters,such as the absolute magnitude, the central velocity dispersion sigma,and the mean surface brightness mu is explored. A sample of 743 E and SOgalaxies is used which is based on three independent radio surveys ofoptically selected galaxies with virtually complete information onmagnitudes, morphological types, redshift distances, diameters, andradio fluxes. For both E and SO galaxies, only the absolute magnitudeappears to be directly related to the radio activity, while sigma and mudo not. Also, a significant dependence of the apparent flattening onradio power is confirmed for E galaxies. Some relevant implications ofthese results are discussed.
|Radio sources in giant E and S0 galaxies|
An optically selected sample of 67 giant E and S0 galaxies has beenobserved with radio telescopes of high sensitivity to low-brightnessemission. Correlations between radio emission and galaxy type andbetween radio emission and environment are confirmed, and the fractionof E galaxies with M(B) less than -21.75 that have radio powers Pgreater than 10 to the 23rd W/Hz at 2380 MHz is found to be 0.4 + or -0.1. For all of the 19 sources with P greater than 10 to the 23rd W/Hzthere is evidence on high-resolution maps of continuing centralactivity. Sensitive observations at 151 MHz are used to put limits onthe number of steep-spectrum radio sources, which may be relics of pastactivity in other sample galaxies, more effectively than has previouslybeen possible. Based on the expected lifetime at 151 MHz of radiativelydecaying sources, the time-scale over which typical radio galaxiesremain active is determined to be greater than a few billion yr. This isin conflict with the small linear sizes of many radio sources in thissample, and it is likely that other effects (such as expansion losses inunconfined sources) render the older parts of these objects invisible.
|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.
|Uppsala General Catalogue of Galaxies. Data for 12,921 galaxies north of delta =-2 30.|
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