Astrophys. J., 685, 235-246 (2008/September-3)
The luminosity dependence of the galaxy merger rate.
PATTON D.R. and ATFIELD J.E.
Abstract (from CDS):
We measure the number of companions per galaxy (Nc) as a function of r-band absolute magnitude for both the Sloan Digital Sky Survey and the Croton and coworkers semianalytic catalog applied to the Millennium Run simulation. For close pairs with projected separations of 5-20 h–1 kpc, velocity differences less than 500 km/s, and luminosity ratios between 1:2 and 2:1, we find good agreement between the observations and simulations, with Nc consistently close to 0.02 over the range -22<Mr←18. For larger pair separations, Nc(Mr) instead becomes increasingly steep toward the faint end, implying that luminosity-dependent clustering plays an important role on small scales. Using the simulations to assess and correct for projection effects, we infer that the real-space Nc(Mr) for close pairs peaks at about M* and declines by at least a factor of 2 as Mr becomes fainter. Conversely, by measuring the number density of close companions, we estimate that at least 90% of all major mergers occur between galaxies which are fainter than L*. Finally, measurements of the luminosity density of close companions indicate that L* galaxies likely dominate in terms of the overall importance of major mergers in the evolution of galaxy populations at low redshift.
Galaxies: Evolution - Galaxies: Interactions - Galaxies: Statistics - Surveys
VizieR on-line data:
<Available at CDS (J/ApJ/685/235): table1.dat>
Table 1: [PA2008] DDD.dddddd+DD.ddddd N=316.
ID col.1 et col.6 not used in SIMBAD
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