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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.
| Models and observations of starbursts. II - Starbursts in interacting galaxies
Evolutionary models are applied here to starburst galaxies in a sampleof 30 interacting or merged systems in order to determine the durationof the starbursts. The time delay between bursts in both components ofinteracting pairs of disk galaxies is investigated and it is found thatstarbursts in the minor galaxies of these pairs started earlier thanthose in the major galaxies. While strong starbursts are found to beactive for only about 2 x 10 exp 7 yrs, the time delay between thebursts in both components of the interacting pairs can be significantlylarger. Delays of up to 2 x 10 exp 8 yrs are found in the sample. Modelfits show that the mass-to-luminosity ratios of strong centralstarbursts indicate a deficiency of low-mass stars in the starburstinitial mass function. The required low-mass-star deficiency is smallerthan previously believed.
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