ALMA Phasing Project

The ALMA Phasing Project (APP) is an international project led by Haystack Observatory to develop the hardware and software necessary to turn the Atacama Large Millimeter/submillimeter Array (ALMA) Observatory in northern Chile into the world’s most sensitive millimeter-VLBI station. This capability was fundamental to the Event Horizon Telescope Collaboration’s ability to obtain the world’s first image of a supermassive black hole in 2019. A full description of the APP and the ALMA Phasing System is available.

APP2 Status Summary: Proposed New VLBI Capabilities for Cycle 8

Matthews, Lynn D.; Crew, Geoffrey B. (2026-02-13)

This document contains material proposed for ALMA Cycle 8 as well as a follow-up note provided to the reviewers. The new capabilities were a passive phasing mode (for weaker sources), an ALMA Band 3 pulsar observing mode, ...
Final Report: Enabling New VLBI Science with the ALMA Phasing System - Phase 3 (APP3): An ALMA North America Development Project

Matthews, Lynn D.; Crew, Geoffrey B. (National Radio Astronomy Observatory (NRAO), 2024-07-19)

Executive Summary: This document provides a summary of activities undertaken as part of the ALMA North America Development Project “Enabling New VLBI Science with the ALMA Phasing System - Phase 3 (APP3)”, whose period of ...
Enabling New Science with the ALMA Phasing System - Phase 2 (APP2): An ALMA North America Development Project

Matthews, L. D.; Crew, G. B. (National Radio Astronomy Observatory (NRAO), 2024-10-18)

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 ...