The role of ionized and molecular outflows in quasar evolution

The cosmic downsizing of quasars is still a big puzzle in astronomy and it is commonly believed that the central active galactic nucleus (AGN) must have played a significant role in quenching itself, in a self-regulatory mechanism popularly termed “AGN feedback”. The AGN feedback also plays a crucial role in black hole and host galaxy co-evolution across cosmic time (The M-sigma relation). Here I will discuss the nature and impact of pc scale outflows from AGN, detected in X-rays, popularly known as warm absorbers (WAX sample study, Laha et al. 2014, 2016), and ultra-fast outflows (UFOs), as well as kpc scale outflows detected in IR and sub-mm, popularly known as Molecular outflows (MOX sample study, Laha et al. 2018). These different types of outflows are believed to be strong contenders for removing gas and dust from the vicinity of the super massive black hole and thereby quenching it. Although we largely believe that feedback is an important mechanism by which the quenching happens, it brings us to an interesting question: Is there any fundamental difference between the central engines of the local AGN compared to their high redshift counterparts? Are they simply scaled down (lower black hole mass) versions of their higher redshift counterparts, or are different in some other way? I will present results from sample studies of AGN addressing this issue (Laha et al. 2018, 2020).