Department of Astronomy & Physics
Narrow-line Seyfert 1 galaxies - young rebels of the AGN family
Speaker: Dr. Emilia Jarvela (UC Santa Barbara)
Time: September 13, 2019 - 3:00 PM
Location: Atrium 101
Narrow-line Seyfert 1 galaxies (NLS1s) are young active galactic nuclei (AGN). They harbour low-mass black holes accreting close to or above the Eddington limit and are preferentially hosted by spiral galaxies. So far ~20 NLS1s have been detected at gamma-rays, confirming the presence of powerful relativistic jets in them. This discovery contradicts the conventional view that only supermassive black holes residing in massive ellipticals are able to launch relativistic jets, and urges us to revise the evolution and unification schemes of AGN. On the other hand, NLS1s offer us an unprecedented opportunity to study the first stages of the AGN evolution.
Our knowledge of NLS1s is still very limited, excluding some outstanding individuals. Studying the whole population is challenging due to its seemingly heterogeneous nature; NLS1 class includes sources with powerful relativistic jets, as well as sources that are totally radio-silent. So far it has remained unclear what causes this disparity. To fully exploit their extraordinary nature we need to understand them better as a class.
In this talk I will give an overview of our latest studies aimed at starting to unveil the nature of the NLS1 population, and to clarify their place in the big picture of AGN. To this end, we have performed statistical studies of large samples, concentrating on their large-scale environment properties, and multiproperty principal component analysis. In addition, we have completed targeted studies of smaller samples, investigating, for example, their radio continuum and morphology properties, and host galaxies.