2MASS/SDSS CLOSE MAJOR-MERGER GALAXY PAIRS

Donovan L. Domingue, C. K. Xu, T. H. Jarrett, Y. Cheng
2009 Astrophysical Journal  
We select a close "major-merger candidate" galaxy pair sample in order to calculate the K s luminosity function (LF) and pair fraction representative of the merger/interaction component of galaxy evolution in the local universe. The pair sample (projected separation 5 h −1 kpc r 20 h −1 kpc, K s -band magnitude difference ΔK s 1 mag) is selected by combining the Two Micron All Sky Survey (2MASS) with the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5). The resulting data set contains 340
more » ... set contains 340 galaxies covering 5800 deg 2 . A stellar mass function is also translated from the LF. A differential pair fraction displays nearly constant fraction of galaxy pairs as a function of galaxy mass from 10 9 to 10 11.5 M . The differential pair fraction is less subject to absolute magnitude bias due to survey limitations than the standard total pair fraction. These results suggest that major-merger candidate pairs in the 0< z <0.1 universe are developed from ∼1.6% of the galaxy population without dependence on galaxy mass for pair components below 10 11 M . The derived LF combined with merger model timescales give local merger rates per unit volume which decrease with masses greater than 10 11 M .
doi:10.1088/0004-637x/695/2/1559 fatcat:asq2tlb6g5a7jgwsp7rdnwrvha