An upper limit to the dry merger rate at ~ 0.55

Roberto De Propris, Simon P Driver, Matthew Colless, Michael John Drinkwater, Jon Loveday, Nicholas P Ross, Joss Bland-Hawthorn, Donald G York, Kevin Alan Pimbblet

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24 Citations (Scopus)


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.
Original languageEnglish
Pages (from-to)794 - 802
Number of pages9
JournalThe Astronomical Journal
Issue number2
Publication statusPublished - 2010
Externally publishedYes

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