PhD Thesis of David R. Patton
Institution: University of Victoria
Date: June 30, 1999
Title: Close Pairs of Galaxies and Merger Rate Evolution
at Redshift Less Than 0.5
Abstract:
New techniques are developed for relating the statistics
of close galaxy pairs to the galaxy merger and accretion
rates.
Unlike the traditional pair fraction approach, these methods are
shown to be robust to a number of selection effects
related to the depth and completeness of the sample.
These techniques are applied to the large, well-defined
SSRS2 (z~ 0) and CNOC2 (0.1 < z < 0.55)
redshift surveys, yielding the first secure measurements
of close pair statistics at low and moderate redshift.
These results imply that the galaxy merger and accretion
rates increase with redshift, approximately as
(1+z)^(2+/-1.5), for galaxies brighter than M(B)=-18.
The CNOC2 survey is used to carry out a detailed comparison
between close companions and field galaxies. Paired galaxies
are found to be of slightly earlier spectral type, with
a larger spread in properties. In particular, the
spectral indices of close companions imply a more complex
star formation history, as would be expected if galaxy
interactions and mergers are prevalent.
Postscript Chapter by Chapter
David Patton <patton@astro.utoronto.ca>
Last modified: Tue Aug 17 08:27:37 1999