Oral Presentation

Stellar Mass Selected Galaxy Mergers at z < 1

Author(s): Ryan Keenan (ASIAA), Sebastien Foucaud (SJTU), Roberto de Propris (U. Turku), Bau-Ching Hsieh (ASIAA), Lihwai Lin (ASIAA), Richard Chou (ASIAA), Shan Huang (ASIAA), Jing-Hua Lin (NTU), Kai-Hung Chang (NTU)

Presenter: Ryan Keenan (ASIAA)

In this study we use the largest ever stellar mass selected sample of galaxies to characterize the pair fraction of major-merger candidate galaxies as a function of stellar mass and redshift. We find the pair fraction to be ~50% higher at z~0 than previous stellar mass selected samples. This is mostly due to the improvement in detection of close pairs in UKIDSS over 2MASS. We find essentially no evolution in the pair fraction out to z=0.8 for galaxies with stellar masses of M~10^11 M_sun. We demonstrate that much of the discrepancy between previous studies of the pair fraction or merger rate evolution is most likely due to cosmic variance. By contrast, we find that the systematics due to cosmic variance in our sample should be ~10%, making this the best measurement to date of the pair fraction evolution.