2014ApJ...795..157K -
Astrophys. J., 795, 157 (2014/November-2)
Evolution of the major merger galaxy pair fraction at z < 1.
KEENAN R.C., FOUCAUD S., DE PROPRIS R., HSIEH B.C., LIN L., CHOU R.C.Y., HUANG S., LIN J.H. and CHANG K.H.
Abstract (from CDS):
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 fpair∝(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).
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Journal keyword(s):
galaxies: evolution - galaxies: formation - galaxies: interactions
Simbad objects:
3
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