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RCW summary - including link for virtual summit tour

RCW talks as YouTube playlist

MNRAS has recently published an article by Brian Bichang’a and collaborators (including Sugata Kaviraj and Aaron Watkins ) on the topic of active galactic nuclei (AGN) in dwarf galaxies.

While the incidence of AGN and their impact on galaxy evolution have been extensively studied in massive galaxies, much less is known about the role of AGN in the evolution of dwarfs. The paper, The properties of AGN in dwarf galaxies identified via SED fitting, explores the incidence of AGN in 508 dwarfs, probes the correlation between AGN activity and factors such as environment, morphology and the presence of interactions and explores whether there is strong evidence for AGN-driven quenching of star formation in dwarf galaxies. Crucially, the deep optical and near-to-mid infrared data used in this study is similar to what will be available using LSST and ancillary surveys. This study therefore offers a preview of dwarf AGN studies that will become possible using LSST in the near future.  

The study finds that around a third of dwarfs show signs of AGN activity. The AGN reside at similar distances to nodes, filaments, and nearby massive galaxies as the general dwarf population, which indicates that AGN triggering in the dwarf regime is not strongly correlated with local environment. The fraction of AGN hosts with early-type morphology, and those that are interacting, are also indistinguishable from the general dwarf population, suggesting that interactions do not play a significant role in inducing AGN activity in this sample. Finally, the star formation activity in dwarf AGN is only slightly lower than that in the general population, suggesting that the presence of these radiatively efficient AGN does not lead to significant, prompt quenching of star formation in these systems. 

Image Added

Distribution of the fraction of the bolometric luminosity that is contributed by the AGN (f_AGN) in our final sample of 508 dwarf galaxies, which exhibits a bimodality around log f_AGN ∼ −2.8. The red histogram denotes galaxies that are defined to be AGN. These are galaxies that have log f_AGN > −2.8 and in which including the AGN in the SED fitting improves the quality of the fit (i.e. the χ² value of the best-fitting model with an AGN template included is smaller than its counterpart without an AGN). The grey histogram corresponds to galaxies that are classified as non-AGN. These are systems that either have log f_AGN < −2.8 or where log f_AGN > −2.8 but including the AGN does not result in a better fit (see the text in Section 4.1 of the paper for more details)