Research
One of the remarkable properties of active galactic nuclei (AGN) is their variability, which is seen in a wide range of the electromagnetic spectrum. Investigating this variability has been essential in finding and understanding the physics of AGN, and that is exactly what my research focused on!
During my four years of PhD, I gained expertise in the field of observational extragalactic astronomy, including the use of catalogs, preparing observing proposals and analyzing the light curve variability of massive datasets. Through my collaboration with the Automatic Learning for the Rapid Classification of Events team (ALeRCE, a Chilean-led broker that analyzes the Zwicky Transient Facility -ZTF- alert stream and one of the Rubin Observatory Full-Stream Alert Brokers) and my internship at Caltech working with ZTF light curves I contributed to the finding and understanding of rare AGN, such as the changing look AGN. This effort resulted in several accepted observing proposals and three papers (Lopez-Navas et al. 2022, 2023a, 2023b) .
I also have a deep understanding of X–ray spectroscopy, gained through my internships at the Instituto de Astrofísica de Canarias (IAC, Spain, Armas-Padilla M. and Lopez-Navas E. 2019) and the Anton Pannekoek Institute for Astronomy (API, University of Amsterdam, Lopez-Navas et al. 2020) working with Swift and XMM-Newton data, and I applied this knowledge in other collaborations (R. Carraro et al. 2020, P. da Silva et al. 2021, Y. Diaz et al. 2022).
AGN have diverse observed properties, but most of these can described by a single unified model, which takes as a parameter the viewing angle of this system. In particular, in the optical classification we have Type 1 and Type 2 AGN. Type 1 refers to AGN whose nucleus is visible: the optical spectrum has both narrow and broad emission lines, while in Type 2 AGN the broad line region (BLR in the illustration) and the disk are obscured by the torus so we cannot see neither the broad lines nor the optical continuum from the disk. However, in recent years astronomers have discovered AGN that do not conform with this picture: the changing look AGN, which display an appearance or disappearance of their optical broad emission lines on time scales from months to years (which cannot be attributed to a change of orientation!). The origin of the CL phenomenon is not very well understood yet, but most studies suggest that these sources could be suffering dramatic changes intrinsic to the accretion flow.