Monday

The hierarchical nature of ΛCDM cosmology points to mergers as a natural channel through which structures in the Universe form and evolve. Galaxy mergers are thought to be an important mechanism driving the evolution of some galaxies towards and along the red sequence but their exact role in the complex picture of galaxy evolution remains unclear. A major difficulty in the observational study of galaxy mergers is that most morphological signatures they leave behind fade away on short timescales and those that prevail the longest, like tidal tails or shells, are of low surface brightness. In image analysis, the widely used merger indicators such as the asymmetry parameter (Conselice et al. 2000) or Gini-M20 relation (Lotz et al. 2004) allow for a robust detection of early merger stages characterised by a double nucleus and/or significant disturbance in the system’s light distribution. However, they do not trace the low surface-brightness tidal features that may linger in the outskirts of post-mergers for an extended period of time after the coalescence. I will show that such features can be detected in currently available data sets using the `shape asymmetry’ parameter (Pawlik et al. 2016) and discuss how the characteristic timescale of visibility of post-merger features, detectable with the shape asymmetry, can be extended using data from upcoming deep surveys like the LSST.