The second u-band extension of the WINGS cluster survey ? ??

摘要

Context. This is the second u -band extension of the WIde-field Nearby Galaxy-cluster Survey (WINGS) whereby 39 clusters were imaged with the ESO-VLT survey telescope. This follows the first part of the survey which was performed with several telescopes of the northern hemisphere in the U Cousin–Bessel filter band covering 17 clusters. Aims. The u -band data, in combination with those already collected by the WINGS survey, permit a detailed multi-wavelength investigation of the properties of the member galaxies from the cluster center out to the periphery. Methods. We used SExtractor to derive the main properties of the galaxies in the observed fields and measure the u ??? V colors on circular apertures of increasing radius. The photometric accuracy of the magnitudes was calibrated with the standard stars and was tested by means of comparisons with the u -band data of the Sloan Digital Sky Survey (SDSS). Results. We present the catalogs of the photometric analysis performed by SExtractor . We also provide a brief analysis of the u ??? V versus V color–magnitude diagram of our clusters, the plots of the color as a function of the cluster-centric distance (for cluster members only), the mass–color relation and the correlation of the current star formation rate (SFR) with the absolute V and u magnitudes for the galaxies in the observed fields.