Data: 21.05.2024

Raphael Oliveira (OAUW)

Star clusters as valuable tracers of their host galaxy

Streszczenie:
Star clusters are often referred to as fossil relics or chemical clocks, since they record the dynamical and chemical conditions during the galaxy formation and evolution. Surveys and instruments with increasingly deeper and high-precision photometry allow to derive precise ages, metallicity, mass and distances from color-magnitude diagrams, as well as structural properties from the distribution and kinematics of stars. Old, metal-poor globular clusters populate the Milky Way bulge and halo, have undergone dynamical relaxation and host multiple stellar populations, revealed by the Hubble Space Telescope. The SIRIUS code has been widely applied by our group to find the Galactic building blocks in the bulge, using priors in metallicity and distance from spectroscopy and RR Lyrae stars, respectively. Farther away, clusters in the Magellanic Clouds (LMC-SMC pair) help to disentangle their mutual dynamical evolution around the Milky Way, with recent collisions and epochs of star formation. The VISCACHA survey provides the best data in terms of photometric depth and image quality for a large number of clusters, with analyses of different regions of the LMC and SMC, and development of open-source tools for parameter derivation and completeness correction. The assembly history of the Magellanic Bridge was the main topic of my PhD research, leading to the identification of clusters formed in-situ vs. those stripped from the SMC, two metallicity dips in the age-metallicity relation and a new estimate for the Bridge stellar mass. In this talk, I will present the findings of my PhD thesis and subsequent research, including new tools and spectroscopic observations.

Bio

Raphael A. P. Oliveira is currently a postdoc at the Astronomical Observatory, working on the detection and modeling of microlensing binaries. Received his PhD from the University of São Paulo in 2023, with a broad experience in the study of star clusters. Active participant of the VISCACHA and LSST surveys, MOSAIC-ELT instrumentation group, and the COIN initiative.