Cake Talk by Kiana Kade

The process of massive galaxy evolution at high redshift is poorly understood, including the co-evolution of central supermassive black hole and stellar mass, and the effects of the black hole on the host galaxy. The role of environment, such as galaxy mergers and feedback, in the rapid build-up of stellar mass during intense starbursts also presents open questions.

In this talk I will present the case of two extreme galaxies at high redshift (AzTEC-3 at z=5.3 and BRI0952-0115 at z=4.432) using deep, high-resolution ALMA band 7 observations. We find complex broad emission line profiles in the [CII] line structure of both sources, indicating the presence of outflows. Within a radius of approximately 19 kpc, we detect companion sources in [CII] emission surrounding both galaxies, with one showing a possible fueling mechanism in the form of a 'gas bridge' structure. In addition, by combining band 7 data and ancillary ALMA archival data, we detect multiple emission lines including [CI], CO, H2O, OH, and OH+ in the quasar BRI0952-0115, allowing for an in-depth study of excitation mechanisms within the ISM and an investigation of the interplay between the AGN and star formation. We compare our results to recent studies of AGN host galaxies at z~3-5 and discuss the potential for furthering our understanding of high-z galaxy ISM and environment.