An Upper Limit to the Dy Merger Rate at (z) ~ 0.55

de Propris, Roberto, Driver, Simon P., Colless, Matthew, Drinkwater, Michel J., Loveday, Jon, Ross, Nicholas P., Bland-Hawthorn, Joss, York, Donald G. and Pimbblet, Kevin A. (2010) An Upper Limit to the Dy Merger Rate at (z) ~ 0.55. Astronomical Journal, 139 (2). pp. 794-802. ISSN 0004-6256

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We measure the fraction of luminous red galaxies (LRGs) in dynamically close pairs (with projected separation less than 20 h(-1) kpc and velocity difference less than 500 km s(-1)) to estimate the dry merger rate for galaxies with -23 < M(r)(k+e,z=0.2) + 5 log h < -21.5 and 0.45 < z < 0.65 in the 2dF-SDSS LRG and QSO (2SLAQ) redshift survey. For galaxies with a luminosity ratio of 1:4 or greater we determine a 5 sigma upper limit to the merger fraction of 1.1% and a merger rate of < 0.8 x 10(-5) Mpc(-3) Gyr(-1) (assuming that all pairs merge on the shortest possible timescale set by dynamical friction). This is significantly smaller than predicted by theoretical models and suggests that major dry mergers do not contribute to the formation of the red sequence at z < 0.7.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Depositing User: Jonathan Loveday
Date Deposited: 06 Feb 2012 18:13
Last Modified: 29 Mar 2012 13:48
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