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The next-generation Very Large Array: Project Summary and Update

Sede A. Riccò Via Santa Sofia 78, Catania

Inspired by dramatic discoveries from the Jansky VLA, VLBA, and ALMA, a large collecting area radio interferometer that will open new discovery space from proto-planetary disks to distant galaxies is being designed by the U.S. National Radio Astronomy Observatory (NRAO) and the broad scientific and technical communities. The next-generation VLA (ngVLA), which was strongly endorsed by the Astro2020 Decadal Survey as an essential research facility whose construction should begin this decade, is envisaged as an interferometric array with ten times greater sensitivity and spatial resolution than the current VLA and ALMA, operating in the frequency range of 1.2 - 116 GHz. Replacing both the VLA and VLBA, the ngVLA will be optimized for observations in the spectral region between the superb performance of ALMA at mm and sub-mm wavelengths, and the future Phase I Square Kilometer Array (SKA-1) at decimeter-scale and longer wavelengths. As such, the ngVLA will uniquely tackle a broad range of outstanding scientific questions in modern astronomy by simultaneously delivering the capability to: unveil the formation of Solar System analogues on terrestrial scales; probe the initial conditions for planetary systems and life with astrochemistry; characterize the assembly, structure, and evolution of galaxies from the first billion years to the present; use pulsars in the Galactic center as fundamental tests of gravity; and understand the formation and evolution of stellar and supermassive blackholes in the era of multi-messenger astronomy. In this presentation, I will provide a project update and discuss the overall science case that led to the current technical design of the ngVLA.

Status and future of 21-cm cosmology during the first billion years

Sede A. Riccò Via Santa Sofia 78, Catania

The 21-cm hyperfine line of neutral hydrogen is set to revolutionize studies of the first billion years, spanning the cosmic dawn of the first stars and eventual reionization of our Universe. I will discuss the potential of this probe in learning about the unknown astrophysics of the first galaxies as well as physical cosmology. Current upper limits on the cosmic 21-cm power spectrum already provide new insights into the heating of the intergalactic medium, and the X-ray sources in the first galaxies. I will discuss the upcoming steps, including the main challenges, that will eventually lead to the Nobel prize-worthy 3D map of half of our observable Universe with the Square Kilometer Array (SKA) telescope.