Monday

Galaxies are dynamical objects that evolve and mature over time where both internal and external processes can change the composition and structure of them. Low-mass galaxies constitute an unrivalled sample to determine the effect of these processes due to their typically pristine gas, stellar, and structural components.
The hierarchical structure formation theory is often invoked to explain the origin of the galaxies and AGNs we see today, and this work test the early stages of this process. We assemble a sample of 6,615 low-mass galaxies from the NASA Sloan Atlas with AGN characteristics in an attempt to determine their cosmological histories and the importance of environment as an AGN trigger.
We find that the fraction of low-mass galaxies exhibiting AGN activity is comparable to regular galaxies (~2-5%), and that they tend to be in denser environments than non-AGN galaxies. However, using a WHAN diagram to select AGNs rather than BPT shows no environmental differences between active and regular galaxies. We discuss the implications of these findings.