Bernard Monteiro de Barros Leal

Bernard Monteiro de Barros Leal

Biography

Bernard Leal is a rising senior at Michigan State University majoring in Astrophysics with a minor in Computational Mathematics, Science, and Engineering. His first research experience was with Professor Seth Jacobson on terrestrial planet formation and later studiedX-ray sources in the globular cluster NGC 6528 with Professor Jay Strader and Dr. Kwangmin Oh, exploring their nature and the cluster’s stellar dynamics near the Galactic center. Currently,he works with Professor Erin Kara on a supermassive black hole flare to understand its impact on the surrounding environment. Bernard is also passionate about teaching and outreach. He volunteers at the MSU Observatory’s public nights and serves as an Undergraduate LearningAssistant for physics and astronomy. He plans to pursue a Ph.D. in astrophysics and a career in academia, studying compact binaries, stellar dynamics, and black holes while inspiring the next generation of scientists through research, mentorship, and outreach.

Abstract

Multi-Wavelength Analysis of The Supermassive Black Hole RHS 10

Supermassive black holes (SMBHs) grow by accreting matter from their surroundings. This process releases extremely intense radiation across the electromagnetic spectrum, allowing us to see these systems, known as active galactic nuclei (AGN). AGN unification models explain differences in observed AGN properties because of their orientation relative to the observer. In the past few decades, discovered cases of extreme variability have challenged this model. One case is changing-state AGN (CS-AGN), which refers to variability that results from an intrinsic change on the accretion rate of the SMBH, but what triggers that change and how it happens in timescales shorter than the ones predicted is still unclear.

In 2018, the AGN RHS 10 exhibited a major flare in the optical band, rising and fading over the course of about a year. The goal of this project was to investigate how the system evolved during and after that event, providing insights into the accretion mechanisms of CS-AGN. The analysis combines archival optical data from the Zwicky Transient Facility, the ATLAS survey, and the Sloan Digital Sky Survey to construct light curves and time-resolved optical spectra to examine long-term trends. We used physically motivated accretion disk models and phenomenological gaussian models to attribute the spectral evolution to underlying physical changes in the accretion disk. These results contribute to the growing sample of studied CS-AGN, advancing efforts to understand the physical drivers of such phenomena and broaden our understanding of the extremes of SMBH accretion.