Séminaires : Documents

Strong Gravitational Lensing: A Powerful Magnifying Glass for Resolving High-z Star-Forming Galaxies
Carla Cornil-Baïotto (IFA UV, Chile)

Mapping the dust and the molecular gas distribution at sub-kpc scales is crucial for understanding the physical mechanisms that govern the star formation activity in galaxies. Aided by adaptive optics, near-IR IFU observations for galaxies at the so-called cosmic noon, 1 < z < 3, have shown that a large fraction of the star-forming galaxies exhibit turbulent and clumpy rotating disks. These structures have been also revealed by rest-frame ultraviolet observations with the HST. The higher gas fractions at these redshifts allow the formation of such massive complexes, however, conducting spatially-resolved studies of their internal structure becomes extremely challenging at high redshifts, as our best telescopes lack the resolution to resolve the ISM in galaxies. The strong gravitational lensing phenomenon overcomes this limitation by magnifying background sources located behind massive galaxy clusters, providing an excellent opportunity to resolve distant and typically faint galaxies. In this seminar, we present the ALMA study of an exceptionally bright and extended, strongly lensed, z~2.8 galaxy laying behind the Bullet Cluster, which exhibits one of the highest differential magnifications ever recorded at submillimeter wavelengths (up to 40!). This extreme magnification, combined with our new ALMA 0.2”-resolution of its CO(3-2) and continuum emission, allows us to reach an exceptional ~40-100 parsec resolution in a faint galaxy that is representative of the typical galaxy population at these redshifts. This has enabled exquisite spatially resolved diagnostics of the star-forming properties of the galaxy, including its morpho-kinematic properties, the exploration of Larson's relations, the Schmidt Kennicutt law, and other future projects to be presented at the seminar.