The environment of UV-luminous star-forming galaxies: clues to understanding the high-redshift universe

Tuesday, 12 November 2019 noon — noon MST

AURA Lecture Hall

NOIRLab South Colloquia
LUIDHY SANTANA (PhD Student Observatorio de Valongo, Rio de Janeiro and Gemini South Visiting Student)

High-redshift galaxies are remarkably different from their local counterparts, showing much higher specific star formation rates and irregular morphologies. Nevertheless, it is a significant challenge to determine the impact of the environment and interactions on the formation and evolution of these galaxies, due to the observational challenge of detecting low-luminosity companions. In order to better understand the physical processes related to density and star formation, We study a sample of local analogs (z~0.2) to high-redshift galaxies that present compact morphology, high star formation activity, and are metal-poor with values similar to those observed in Lyman break galaxies at z~ 2-3. To this end, we obtain deep (g ~ 25 mag) images with the Dark Energy Camera of 11 objects, covering approximately 20 Mpc around each one and detecting objects down to 10^8 solar masses. We investigate their surrounding environment to evaluate its impact on star formation properties, comparing results with objects of similar stellar mass and redshift range and discussing the implications for galaxy formation in the early universe. Using the Nearest Neighbour method we obtain 3 environmental measurements for each galaxy in the field that range from small scales (pairs and galaxy groups) to large scales (cluster of galaxies). We find that in small scales the UV-luminous star-forming galaxies populate denser regions. We suggest that close-by encounters nd interactions are an important ingredient in shaping these galaxies, possibly involving galaxy pre-processing in small groups before falling into larger structures.