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Paper: Search for (Tidal) Streams in Disks and Halos
Volume: 396, Formation and Evolution of Galaxy Disks
Page: 289
Authors: Schmithuesen, O.; Bomans, D.J.; Dettmar, R.-J.
Abstract: Here we present results of our ongoing project on the search for tidal streams in disk and halos of galaxies outside the Local Group. At present we have investigated NGC 300, M 83, M 33 and NGC 7793. Most of the data was observed with the Wide-Field-Imager at the ESO/MPG 2.2-m telescope and reduced with the THELI-Pipeline. We carried out stellar photometry on all these images and searched for over-densities in the stellar counts of red giant branch populations. For instance in NGC 300 this search revealed the presence of a break in the red giant branch counts at about 8.75 kpc away from the center and the presence of blue stars all over the field of view. The M 83 images showed three low surface brightness features, of which two were formerly seen only on photographic plates. Using the transformation to the standard magnitude system derived from the stellar sources we were able to calculate an average surface brightness for these three streams. But we did not detect any sign of substructure in the stellar counts itself down to a magnitude limit of 24.5 magnitudes for the stellar sources. Using the M 33 and NGC 7793 datasets we started to introduce an additional search algorithm. While until then the search had been carried out using an adapted binning strategy to reveal such over-densities we experimented using four dimensional cluster-finding algorithms from the field of data-mining as an addition.
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