ALMA is undergoing a major upgrade. It consists of an increase of the instantaneous spectral bandwidth by as much as a factor of four, while retaining full spectral resolution over the entire bandwidth. In addition, an upgrade of the full signal chain of ALMA – from the receivers and digitizers, all the way through to the correlated data. This upgrade will result in increases in sensitivity for all observations, and increases of the spectral scan speed up to a factor of 50 for the highest spectral resolution. ALMA Band 2, the flagship ALMA upgrade project being led by ESO, will be the first receiver to exploit this new, wide bandwidth. 

However, this upgrade also brings some technical challenges related to the increase of the bandwidth needed all the way from the receivers to digitizers, digital signal processing and a 2nd generation correlator.

I will widely present the upgrade and an overview of the science that will be enabled in the upcoming years, during which some changes on scientific operations are expected due to the extent of the upgrade, deployment, and commissioning activities.