We present a study of the largest available sample of near-infrared selected (i.e., stellar mass selected) dynamically close pairs of galaxies at low redshifts (z < 0.3). We combine this sample with new estimates of the major merger pair fraction for stellar mass selected galaxies at z < 0.8, from the Red Sequence Cluster Survey (RCS1). We construct our low-redshift K-band selected sample using photometry from the UKIRT Infrared Deep Sky Survey and the Two Micron All Sky Survey (2MASS) in the K band (∼2.2 μm). Combined with all available spectroscopy, our K-band selected sample contains ∼250, 000 galaxies and is >90% spectroscopically complete. The depth and large volume of this sample allow us to investigate the low-redshift pair fraction and merger rate of galaxies over a wide range in K-band luminosity. We find the major merger pair fraction to be flat at ∼2% as a function of K-band luminosity for galaxies in the range 108-1012 L ⊙, in contrast to recent results from studies in the local group that find a substantially higher low-mass pair fraction. This low-redshift major merger pair fraction is ∼40%-50% higher than previous estimates drawn from K-band samples, which were based on 2MASS photometry alone. Combining with the RCS1 sample, we find a much flatter evolution (m = 0.7 ± 0.1) in the relation f pair∝(1 + z)m than indicated in many previous studies. These results indicate that a typical L ∼ L∗ galaxy has undergone ∼0.2-0.8 major mergers since z = 1 (depending on the assumptions of merger timescale and percentage of pairs that actually merge).
CITATION STYLE
Keenan, R. C., Foucaud, S., De Propris, R., Hsieh, B. C., Lin, L., Chou, R. C. Y., … Chang, K. H. (2014). Evolution of the major merger galaxy pair fraction at z < 1. Astrophysical Journal, 795(2). https://doi.org/10.1088/0004-637X/795/2/157
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