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The Space Density Evolution of Wet and Dry Mergers in the Canada-France-Hawaii Telescope Legacy Survey

Chou, Richard C. Y. and Bridge, Carrie R. and Abraham, Roberto G. (2011) The Space Density Evolution of Wet and Dry Mergers in the Canada-France-Hawaii Telescope Legacy Survey. Astronomical Journal, 141 (3). Art. No. 87. ISSN 0004-6256. doi:10.1088/0004-6256/141/3/87.

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We analyze 1298 merging galaxies with redshifts up to z = 0.7 from the Canada-France-Hawaii Telescope Legacy Survey, taken from the catalog presented in the work of Bridge et al. By analyzing the internal colors of these systems, we show that the so-called wet and dry mergers evolve in different senses, and quantify the space densities of these systems. The local space density of wet mergers is essentially identical to the local space density of dry mergers. The evolution in the total merger rate is modest out to z ~ 0.7, although the wet and dry populations have different evolutionary trends. At higher redshifts, dry mergers make a smaller contribution to the total merging galaxy population, but this is offset by a roughly equivalent increase in the contribution from wet mergers. By comparing the mass density function of early-type galaxies to the corresponding mass density function for merging systems, we show that not all the major mergers with the highest masses (M_(stellar) > 10^(11) M_⊙) will end up with the most massive early-type galaxies, unless the merging timescale is dramatically longer than that usually assumed. On the other hand, the usually assumed merging timescale of ~0.5-1 Gyr is quite consistent with the data if we suppose that only less massive early-type galaxies form via mergers. Since low-intermediate-mass ellipticals are 10-100 times more common than their most massive counterparts, the hierarchical explanation for the origin of early-type galaxies may be correct for the vast majority of early types, even if incorrect for the most massive ones.

Item Type:Article
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URLURL TypeDescription
Abraham, Roberto G.0000-0002-4542-921X
Additional Information:© 2011 American Astronomical Society. Received 2010 April 13; accepted 2010 December 4; published 2011 February 7. The authors thank NSERC and the Government of Ontario for funding this research. We also thank Damien Le Borgne and Karl Glazebrook for useful discussions.
Funding AgencyGrant Number
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Government of OntarioUNSPECIFIED
Subject Keywords:galaxies: evolution – galaxies: formation – galaxies: interactions
Issue or Number:3
Classification Code:PACS: 95.80.+p, 98.62.Py, 98.52.Eh, 98.65.Fz
Record Number:CaltechAUTHORS:20110315-152141116
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Official Citation:Richard C. Y. Chou et al. 2011 The Astronomical Journal 141 87 doi: 10.1088/0004-6256/141/3/87
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:22913
Deposited By: Benjamin Perez
Deposited On:15 Mar 2011 22:38
Last Modified:09 Nov 2021 16:09

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