Education: the morphology of galaxies, as probed by deep imaging

 

Fine structures


The interpretation of the MATLAS images strongly depends on the way fine structures around ETGs are identified. Distinguishing between the various types of structures is not unambiguous:   tidal tails from major mergers may be mistaken with stellar streams from minor ones. Streams wrapping around galaxies resemble shells, etc...

The naming and definition  of collisional debris are furthermore elusive in the literature. In order to help with the identification of fine structures, and the classification of galaxies based on their fine structure index, we present in the links here-below  tentative definitions of tidal tails, stellar streams and shells, give hints on how to recognize them on the MegaCam images, and finally, based on numerical simulations,  give clues on what they may tell about the past mass assembly of galaxies.

Other morphological features


The MegaCam images disclose a number of additional features such as:


Instrumental artifacts, foreground contaminations


At the dept of MATLAS, several additional features not visible in regular images pop up, and should be identified, masked or subtracted. These are:

  1. Distorted halos

  1. Bars