The effect of mergers on galaxy formation and evolution [Elektronische Ressource] / put forward by Rosalind Eugenie Skelton

DISSERTATIONSUBMITTED TO THECOMBINED FACULTIES FOR THE NATURAL SCIENCES AND MATHEMATICSOF THE RUPERTO CAROLA UNIVERSITY OF HEIDELBERG, GERMANYFOR THE DEGREE OFDOCTOR OF NATURAL SCIENCESPUT FORWARD BYROSALIND EUGENIE SKELTONBORN IN: JOHANNESBURG, SOUTH AFRICAthORAL EXAMINATION: FEBRUARY25 , 2010THE EFFECT OF MERGERS ON GALAXYFORMATION AND EVOLUTIONREFEREES: PROF. DR. HANS WALTER RIXPROF. DR. ERIC F. BELLTo my granny Pat,a constant source of inspiration and loveSummaryThis thesis explores the effect of galaxy mergers on the evolution of galaxies over the last8 billion years using the merger trees from a semi analytic model (SAM) of galaxy formation.The SAM produces reasonable agreement with the distribution of mass, luminosity and colourat low redshifts, as well as the observed merger fractions. I revisit two apparent contradictionsbetween the standard hierarchical model of galaxy formation and observations of early typegalaxies, using the galaxy merger trees as the basis for further modelling. The observed colour–magnitude relation from the Sloan Digital Sky Survey has a change in slope and smaller scatterat the bright end. A simple toy model shows that dry mergers produce similar characteristics.Contrary to previous claims, the small scatter in the observed CMR thus cannot be used toconstrain the amount of dry merging.