Donaji Esparza-Arredondo, Omaira Gonzalez-Martin, Deborah Dultzin, Almudena Alonso-Herrero, Cristina Ramos Almeida, Tanio Diaz-Santos, Ismael Garcia-Bernete, Mariela Martinez-Paredes, Jose Miguel Rodriguez-Espinosa. 2018. Circumnuclear Star Formation and AGN Activity: Clues from Surface Brightness Radial Profile of PAHs and [S IV]. Astrophysical Journal 859, 2, DOI: 10.3847/1538-4357/aabcbc
We studied the circumnuclear mid-IR emission in a sample of 19 local active galactic nuclei (AGNs) with high spatial resolution spectra using T-ReCS (Gemini) and CanariCam (GTC), together with Spitzer/IRS observations. We measured the flux and the equivalent width for the 11.3 mu m PAH feature and the [S IV] line emission as a function of galactocentric distance. This allowed us to study the star formation (SF) at subkiloparsec scales from the nucleus for a large sample of nearby AGNs. The [S IV] line emission could be tracing the AGN radiation field within a few thousand times the sublimation radius (R-sub), but it often peaks at distances greater than 1000 R-sub. One possibility is that the SF is contributing to the [S IV] total flux. We found an 11.3 mu m PAH emission deficit within the inner few tens of parsecs from the AGN. This deficit might be due to the destruction of the molecules responsible for this feature or the lack of SF at these distances. We found a sensible agreement in the expected shift of the relation of the AGN bolometric luminosity and the SF rate. This indicates that numerical models attributing the link between AGN activity and host galaxy growth to mergers are in agreement with our data, for most inner galaxy parts.
