Abstract :
Quasars are among the most luminous objects in the universe. These extremely energetic regions lie at the centers of massive galaxies and are powered by supermassive black holes. While it has been found that there is a correlation between the mass of these supermassive black holes and the mass of the surrounding galaxies, the co-evolution of galaxies and quasars is barely understood. One possible link is provided by outflows — fast-moving gas launched from the vicinity of supermassive black holes. These outflows may regulate both black hole growth and star formation, making them a key piece in understanding the co-evolution of galaxies and quasars. A newly identified class of outflows, called extremely high velocity outflows (EHVOs), may be particularly important in this process as it is likely the most powerful in terms of mass energy due to their speeds larger than 10% the speed of light. These powerful outflows have been observed across a wide range of redshifts, including several cases among the few known quasars at z > 7, making them relevant to the earliest stages of galaxy formation.
My research group — composed primarily of undergraduate students— has recently discovered almost 140 new EHVOs, expanding the known sample by a factor of 20. This larger dataset allows us to investigate fundamental questions about the nature of these outflows and the quasars in which they are found. I will present our latest findings, including evidence that these powerful outflows are more common in quasars whose spectra show strong blueshifts in the CIV emission line — providing the first indication that quasars with EHVOs also exhibit outflows in emission. Additionally, we find that their quasars tend to have distinct physical properties, such as higher luminosities and Eddington ratios, compared to quasars with slower outflows. Finally, I will discuss recent results on how EHVOs evolve over time, as well as new simulations that help us understand where these outflows originate and what conditions are needed to launch them. Understanding EHVOs throughout cosmic history, particularly now that they are being detected at very high redshifts, may be crucial for solving the puzzle of galaxy evolution.
