APEX Extension Agreement Signed

An extension of the agreement between the partners of the Atacama Pathfinder Experiment (APEX) has been signed, ensuring that this very productive collaboration will continue until the end of 2022. The 12-metre APEX telescope saw first light in 2005 and has provided astronomers with detailed views of the coldest objects and processes in the Universe.

APEX is a collaborative effort between the Max-Planck-Institute for Radio Astronomy (MPIfR) in Bonn, Germany,  ESO and the Onsala Space Observatory (OSO) in Onsala, Sweden, and the agreement was signed by ESO’s Director General, Tim de Zeeuw, Karl Menten, Director at the Max-Planck-Institut für Radioastronomie and John Conway, Director of the Onsala Space Observatory. The ceremony took place at Chalmers University of Technology in Gothenburg, Sweden.

Under the APEX extension agreement, the telescope will be upgraded to significantly improve the overall observing efficiency, and the suite of instruments will be upgraded to a new generation. These new instruments include several prototype receivers for ALMA, opening up new atmospheric windows (eso1543) and increasing the bandwidth of existing receivers. In order to better accommodate the high demand for APEX from the ESO community, ESO’s share will increase from 27% to 32%. The MPIfR share will also increase from 50% to 55%, while the OSO share will decrease from 23% to 13%.

APEX is designed to work at sub-millimetre wavelengths between infrared light and radio waves, from 0.2 to 1.9 millimetres, which is key to revealing some of the coldest material in the Universe. Over the years, it has shed light on a wide range of astronomical phenomena. It has probed the wild early lives of today’s most massive galaxies (eso1206), studied matter torn apart by a supermassive black hole (eso0841), and mapped the plane of the Milky Way at submillimetre wavelengths (eso1606). It also detected molecules of hydrogen peroxide in interstellar space for the first time (eso1123), solved a centuries-old mystery of a stellar collision (eso1511), and — in conjunction with other telescopes around the world — observed the heart of a distant quasar, producing images two million times sharper than human vision (eso1229).

Because sub-millimetre radiation from space is heavily absorbed by water vapour in the Earth’s atmosphere, APEX is located at an altitude of 5100 metres on the Chajnantor plateau in Chile’s Atacama Desert, one of the driest places on Earth, where unsurpassed observing opportunities are available.

As its name implies, APEX is the pathfinder to the ALMA project. It is a modified ALMA prototype antenna and shares the site of the ALMA observatory, which is itself now fully operational as the world’s largest ground-based facility for observations in the millimetre/submillimetre regime. ALMA comprises a giant array of fifty-four 12-metre antennas and twelve 7-metre antennas, which — thanks to the pioneering efforts of APEX — enables transformational research into the physics of the cold Universe, probing the first stars and galaxies, and directly imaging the formation of planets. Several of APEX’s strengths, such as its capability to map very wide areas, are highly complementary to ALMA.

With the extension of the agreement to 2022, the European user community will continue to benefit from this privileged opportunity to optimally prepare for ALMA follow-up programmes and APEX will continue to probe the cold and distant Universe, undoubtedly contributing further exciting discoveries.

More Information

APEX is a collaboration between the Max-Planck-Institut für Radioastronomie (MPIfR), Onsala Space Observatory (OSO), and the  European Southern Observatory (ESO). The telescope was designed and constructed by  VERTEX Antennentechnik GmbH (Germany), under contract to MPIfR, and is based on a prototype antenna constructed for the  ALMA project. Operation of APEX in Chile is entrusted to ESO.

Courtesy of European Southern Observatory