Oral Presentation

Compaction in Obscured AGN Hosts

Author(s): Emeric Le Floc'h(CEA); Stephanie Juneau(CEA); Elisabete da Cunha(ANU); Mara Salvato(MPE); Avishai Dekel(Hebrew U); Francesca Civano(CfA); Stefano Marchesi(Clemson U); Hyewon Suh(Hawaii U); Wei-Hao Wang(ASIAA)

Presenter: Yu-Yen Chang (ASIAA)

The processes driving the co-evolution of galaxies and their super-massive black holes largely remain a debated issue in extragalactic astrophysics. Using HST imaging, we found that the radial I-band light profile of obscured AGN host galaxies at z~1 is more compact than that of star-forming sources at similar redshift and stellar mass, and that it is not due to the contribution of a passive stellar component. It could thus pinpoint an increased activity of central star formation possibly triggered by a phase of gas compaction. Indeed such AGN hosts are actively forming stars, but where this star formation occurs is still unconstrained. With our incoming Cycle 4 high-resolution ALMA Band 7 data, we will derive dust maps of 10 obscured AGN hosts. This will allow us constraining their star formation surface density without AGN contamination, and investigating if the spatial distribution of young stars follows that of the compact visible disk. We are also preparing cycle-5 proposal to investigate emission lines from molecular gas, as well as larger sample. The goal is to address whether the obscured black hole accretion phase is related to galaxies experiencing a compaction of their gaseous component, which could play a key role in the final quenching mechanisms driving the formation of passive red sources.