Record Amount of Time Requested in Cycle 4 Proposals for ALMA

23 August 2016

A record amount of observing time was requested by the international astronomy community under the call for proposals as part of Cycle 4 at the Atacama Large Millimeter/submillimeter Array (ALMA). The high demand for this revolutionary telescope was reflected in 50% more requested hours compared to the previous ALMA cycle.

Over 400 astronomers were granted observing time with ALMA, the most powerful radio telescope on Earth. The selection process took almost five months, with specialists from around the world meeting in Vienna, Austria, last June to evaluate the 1571 proposals for observing time. The 145 science advisors of the ALMA Proposal Review Committee met for a week to establish the criteria and a ranking to make the selection of proposals as objective as possible. This involved considering the many different aspects that determine the scientific importance and technical feasibility of a project, as well as its likelihood of success. The experts then conducted an exhaustive review of each proposal based on these criteria.

The total amount of observing time represented by the 1571 correctly submitted proposals from more than 30 countries came to 18 630 hours (12 285 hours for the 12-metre Array and 6345 hours for the Compact Array). In total 3000 hours for the 12-metre Array and 1800 hours for the Compact Array were allocated.

The category with the most proposals requested and selected — about one in every four — was “Interstellar Medium, Star Formation and Astrochemistry”. “Cosmology and High Redshift Universe”; “Galaxies and Galactic Nuclei”; “Circumstellar Discs, Exoplanets and the Solar System” accounts each for about one of every five proposals, while “Stellar Evolution and the Sun” accounts for about one in ten.

Cycle 4 observations will begin in October 2016 and end in September 2017, and will include a total of 476 selected proposals. The proposals selected will have access to at least fifty-three ALMA antennas to search the Universe — forty-three 12-metre antennas and ten 7-metre antennas — at millimetre and submillimetre wavelengths, using seven receivers (Bands 3, 4, 6, 7, 8, 9 and 10). ALMA will be able to observe with a maximum angular resolution of 0.029 arc-seconds, using a 12.6-kilometre maximum baseline.

More Information

ALMA, an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile.


Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591

About the Announcement



Description of ALMA Cycle 4 main new capabilities
Description of ALMA Cycle 4 main new capabilities
Locations of ALMA Cycle 4 proposers
Locations of ALMA Cycle 4 proposers
Breakdown of ALMA Cycle 4 accepted proposals by science category
Breakdown of ALMA Cycle 4 accepted proposals by science category