Enabling New Science with the ALMA Phasing System - Phase 2 (APP2): An ALMA North America Development Project

Abstract

This document provides a summary of activities undertaken as part of the Cycle 5 ALMA North America Development Project “Enabling New Science with the ALMA Phasing System - Phase 2 (APP2)”, whose period of performance extended from January 1, 2018 to August 31, 2024. APP2 provided a series of enhancements to ALMA’s very long baseline interferometry (VLBI) and phased array capabilities, leading to the introduction of submillimeter (Band 7) phasing and VLBI capabilities, a passive phasing mode, a Phased Array (pulsar) observing mode, a prototype spectral line VLBI capability, an improved method of handling baseband delays, and a number of other minor system enhancements.