Welcome to our A3COSMOS home page!

Data version 20250312 is now available.

A3COSMOS is a joint project between the astronomical research groups of Argelander-Institut für Astronomie, Universität Bonn (AIfA group) and Max-Planck-Institut für Astronomie (MPIA group) for the full exploration of the Atacama Large Millimeter/submillimeter Array (ALMA) observations toward millions of galaxies in the COSMOS two square degree sky. 

Project description

COSMOS is a two square degree field in the sky. About 1.3 million galaxies have been found within this patch of sky. These galaxies lived in different epochs of the Universe, from as early as 750 Mega years after the Big Bang to the present time, which is about 13 billion years after the Big Bang. Our project goal is to use the numerous ALMA observations to best understand these galaxies, for example, by measuring their star formation and interstellar medium properties, and measuring their cosmic evolution, as well as to provide best (sub-)millimeter ((sub)mm) image and catalog data sets to the COSMOS collaboration and the whole astronomical community. 

ALMA is a most powerful (sub)mm interferometry array. It observes the (sub)mm photons mainly emitted by the dust grains in galaxies. Dust grains in galaxies are closely related to the gas contents and star formation in galaxies, thus (sub)mm observations are indispensable for galaxies' dust, gas, and star formation studies. Currently, ALMA observations are proposed by individual Principal Investigators (PIs) who are able to observe small samples of a few to a few hundred targets of interest. The COSMOS field is extremely large compared to the ALMA field of view, thus no suitable single survey could be conducted (which needs ~13,742 pointings or ~500 hours to cover the whole COSMOS field down to an r.m.s. of ~0.1 milli-Jansky at 1.25 mm). However, by exploiting the growing ALMA science archive, we are able to cover an ever-increasing fraction of the COSMOS field. 

Based on these ideas, we started this project at the beginning of 2017. The AIfA group (B. Magnelli [now at CEA Saclay], A. Karim, et al.) processed all publicly available ALMA archive in the COSMOS field and provided the interferometric uv data, dirty and clean image data and all related metadata. The AIfA group also ran blind source extraction (Karim et al. 2013) on the image data and provided a blind extraction catalog. The MPIA group (E. Schinnerer, D. Liu, P. Lang, et al.) compiled all available multi-wavelength information for galaxies in the COSMOS field, identified counterparts for the blindly extracted ALMA sources, as well as ran prior source extraction tool to the image data and provided a prior extraction catalog. Further value add-on products are also under construction, for example, multi-wavelength spectral energy distribution data etc. Due to the growing of the ALMA archive, the above process is repeated on a regular basis.

Since mid-2020, we have also extended our A3COSMOS efforts to the publicly available ALMA data in the GOODS-South field, accordingly called A3GOODSS.

Data Release

Version: 20250312 (click to see download links)

Paper I – Data & Catalog: ADS Link | arXiv Link

Paper II – Cosmic Gas Evolution: ADS Link | arXiv Link

Python package for computation of the gas scaling relations in Paper II: PyPI/a3cosmos-gas-evolution

Paper VII – A3GOODSS Data & Catalogs: ADS Link | arXiv Link

Contact

If you have interest, please contact:

sadscheid @ astro.uni-bonn.de for galaxy catalogs and database maintenance

benjamin.magnelli @ cea.fr for ALMA images

dzliu @ pmo.ac.cn for SEDs and other stuff