World's largest radio telescope array reveals detailed map of Milky Way center

The ALMA ACES survey produced the largest radio mosaic ever made of the Milky Way's Central Molecular Zone, showing complex filaments of cold molecular gas and dozens of identified molecules; the results were published Feb. 25 in Monthly Notices of the Royal Astronomical Society.

Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have mapped the Central Molecular Zone (CMZ) of the Milky Way in unprecedented radio detail. The CMZ is a roughly 650-light-year-wide region around the galaxy's center that contains dense, cold gas and lies near the supermassive black hole Sagittarius A*. The ACES (ALMA CMZ Exploration Survey) mosaic is the largest image ALMA has ever produced and was assembled from many individual antenna observations. The research was published on Feb. 25 in Monthly Notices of the Royal Astronomical Society. Key findings: - The ALMA ACES survey produced the largest-area radio mosaic ALMA has yet captured of the Central Molecular Zone (about 650 light years across). - The image shows an intricate network of dense, cold gas arranged in filaments and clumps that are capable of forming stars. - Dozens of molecules were detected across the region, including complex organic molecules such as methanol and ethanol and simpler species such as silicon monoxide. - The CMZ hosts some of the most massive stars in the galaxy, many of which have short lifespans and end in powerful supernovae or hypernovas, and the region shares features with galaxies from the early universe. - The mosaic was created by stitching together many smaller ALMA observations made with the array's 66 radio antennas across northern Chile. Summary: The new ALMA mosaic gives astronomers a much more detailed view of the cold molecular gas and its chemistry near the Milky Way's center, which can inform studies of how stars form and die in that extreme environment. The authors note the region's similarities to early-universe galaxies and expect the data to be used to investigate star formation and galaxy evolution. Undetermined at this time.