Isolated Pairs of Galaxies in SDSS

摘要

A search for galaxy pairs was performed in the Sloan Digital Sky Survey, Data Release 6 (SDSS-DR6), using the SQL language. We have analyzed the isolation of these pairs, in a 0.5h_(70)~(-1) Mpc radius. The isolation criteria used are similar to the fossil group ones, where the difference in the r-band magnitude between the brightest galaxy of the pair and the next brightest galaxy is larger than 2, taking into account redshift constraints. Our results show that around 3.5% of all the pairs found in SDSS can be considered isolated, according to the r-band magnitude criterion. We also analyzed properties of the galaxies in the pair, such as their colors, classifying them in early or late types.