Thesis Topic: The effect of AGN on the star formation in their hosts.




Thesis Supervisor: Evanthia Hatziminaglou




Luminous star formation and AGN episodes are fundamental to assembling galaxies at z > 1, but the nature of these episodes, and their connection to each other, remain unclear. In part, this is due to an incomplete understanding of stellar and black hole mass assembly events. Furthermore, it is still unclear if star formation events and AGN activity can directly aff ect one another. A direct relation is motivated by models for galaxy assembly to improve consistency between predictions and observations, most often via `quenching' of star formation by an AGN. However, observational studies of quenching remain inconclusive.

The purpose of the proposed project it to approach the issue of a possible causality between AGN activity and star formation in the AGN population as a whole and on individual objects, at low and high redshifts. The project consists of three parts, namely:

1) The study of star formation on the hosts of optically bright SDSS quasars, hosts of type 2 AGN sample selected based on emission line properties, and a comparison between two type 1 and type 2 samples, matched in optical properties and redshift. Herschel-SPIRE fluxes from the Herschel point source catalogue will be used as indicators of the star formation. 

2) The study of the 29 far-infrared brightest SDSS quasars at 2<z<4 selected from a complete quasar sample, using newly acquired ALMA ACA band 7 data. These data will either confirm that the far infrared fluxes come from single sources, i.e. the quasar hosts, conforming them to be among the most extreme star-formers in the Universe, or will break these fluxes into multiple components, providing new measurements for their star formation rates.

3) The study of outflows in a complete sample of 34 local AGN and their effect on the gas of their hosts, using data that will be taken as part of a successful Cycle 5 ALMA proposal.