Aims. We investigate the influence of major mergers on the radio emission of elliptical galaxies. Methods. We use a complete sample of close pairs, which contains 475 merging and 1828 non-merging paired elliptical galaxies of Mr???21.5 selected from the Sloan Digital Sky Survey. In addition, a control sample of 2000 isolated field galaxies is used for comparison. We cross-identify the optical galaxies with the radio surveys of FIRST and NVSS. Results. We find that the radio fraction of merging paired galaxies is about 6%, which is slightly higher than the 5% obtained for non-merging paired galaxies, although these values are consistent with each other owing to the large uncertainty caused by the limited sample. The radio fraction is twice that of isolated galaxies, which is less than 3%. Conclusions. Radio emission of elliptical galaxies is only slightly affected by major mergers, but depends predominantly on their optical luminosities. We therefore conclude that merging is unimportant in triggering the radio emission of elliptical galaxies.
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机译:目的我们调查主要合并对椭圆星系无线电发射的影响。方法。我们使用完整的近似对样本,其中包含从Sloan Digital Sky Survey选出的475个合并的Mr. <21.5的非合并配对椭圆星系。另外,将2000个隔离的野外星系的对照样品用于比较。我们通过FIRST和NVSS的无线电勘测交叉识别光学星系。结果。我们发现,合并成对星系的射电分数约为6%,这比非合并成对星系的射电分数略高一些,尽管由于数值不确定性较大,这些值彼此一致。有限的样本。射电分数是孤立星系的二分之一,小于3%。结论。椭圆星系的无线电发射仅受到主要合并的轻微影响,但主要取决于它们的光度。因此,我们得出结论,合并对于触发椭圆星系的无线电发射并不重要。
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