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Neutral hydrogen absorption at the centre of NGC 2146
We present 1.4-GHz HI absorption line observations towards thestarburst in NGC 2146, made with the Very Large Array and theMulti-Element Radio-Linked Interferometer Network. The HI gas has arotating disc/ring structure with column densities between 6 and 18× 1021 atom cm-2. The HI absorption has auniform spatial and velocity distribution, and does not reveal anyanomalous material concentration or velocity in the central region ofthe galaxy which might indicate an encounter with another galaxy or afar-evolved merger. We conclude that the signs of an encounter causingthe starburst should be searched for in the outer regions of the galaxy.
| 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.
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