Research

PhD@ INAF_OAAb & GSSI: Constraints on galaxy formation and evolution using old compact stellar systems  

To refine our understanding of the hierarchical assembly of galaxies, it is imperative that we gain a better grasp of how structures evolve over cosmic time. One promising approach to studying galaxy formation and evolution is by examining the population of globular clusters they host. My thesis project primarily focuses on studying GCs within the Hydra I galaxy cluster.

My research plan builds on existing proprietary photometric and spectroscopic data obtained from ESO telescopes. 

Specifically, I will use the following datasets:

i) Deep optical g- and r-band images from OmegaCAM@VST, covering an area of ∼1.5 square degrees around NGC 3311;

ii) Deep near-infrared (NIR) H-band images from VIRCAM@VISTA, also spanning ∼1.5 square degrees around NGC 3311;

iii) Integral-field spectroscopy with MUSE@VLT of 32 Ultra Diffuse Galaxies (UDG) within Hydra I.

MSc Thesis: Extragalactic globular cluster systems: investigating galaxy groups with the VEGAS survey

M. Mirabile et al. 2024

R. Ragusa, M. Mirabile et al. 2022 

Globular cluster systems in groups of galaxies provide valuable insights into galaxy formation and evolution. These dense, spherical collections of old stars are found orbiting galaxies and serve as tracers of a galaxy’s mass, merger history, and dark matter distribution. In galaxy groups, globular clusters can be associated with individual galaxies or exist as intracluster objects, potentially stripped during interactions. Their spatial distribution, metallicity, color and luminosity distribution offer clues about the assembly history of the group, shedding light on the hierarchical formation of galaxies in the cosmic web.

Building on this, during my Master's thesis, I analyzed the globular cluster system in two galaxy groups using wide-field multi-band u, g, r and i observations from the VST telescope. I managed the entire process of detecting point-like sources across the field, including galaxy light modeling and subtraction. I identified bona fide globular cluster candidates based on their morphometric properties (i.e., compactness) and photometric characteristics (i.e., color and magnitude). This allowed me to study their properties and explore their relationship with the host galaxy and surrounding environment.

BCs Thesis: Age of the Galactic globular cluster M13

Globular clusters are bound systems of old stars. Resolved Milky Way globular clusters are those where individual stars can be distinguished and studied in detail. These clusters provide crucial insights into stellar evolution, as they cat as the perfect laboratory where to study the different phases of stellar evolution. Their well-defined color-magnitude diagrams help refine models of stellar aging and distance measurements. By estimating the age of the globular cluster is possible to identify a lower limit to the age of the Universe. 

For my Bachelor's thesis, I observed the Galactic globular cluster M13 using a 50 cm telescope at my university in two different passbands. I handled the entire data reduction process, including bias subtraction and flat-fielding, as well as the photometry of individual stars in the cluster. I corrected my catalog for extinction and obtained a color-magnitude diagram, which I then compared with theoretical models. Specifically, I analyzed the location of the turn-off point, where stars leave the main sequence, to determine which model best reproduced my observed data.