Free Astronomy Magazine January-February 2016

SPACE CHRONICLES a powerful tool for also de- tecting carbon monoxide and ionised carbon in gal- axies in the early Universe. The new SEPIA receiver has been used to make test astronomical observations at APEX during 2015. Identical receivers are be- ing installed in the ALMA antennas. Results from the new detector on APEX have shown it to be work- ing well. With this valida- tion, SEPIA is being made available to the wider sci- entific community. Obser- vations with SEPIA can now be proposed by astrono- mers in the community. "The first measurements with SEPIA on APEX show that we really are opening up a new window, includ- ing looking at water in in- terstellar space — SEPIA will give astronomers a chance to search for ob- jects that can be followed up at higher spatial resolu- tion when the same receiv- er becomes operational on the ALMA array," says John Conway, director of Onsala Space Observatory, Chal- mers University of Techno- logy in Sweden. Just as dark skies are essen- tial to see faint objects in visible light, a very dry atmosphere is needed to pick up the signals from water in the cosmos at longer wavelengths. But dry conditions are not the only requirement, the de- tectors need to be cooled to a very low temperature of –269 degrees Celsius — just 4 degrees above ab- solute zero — for them to work. Recent technological advancements have only now made these detec- tors possible and practical. APEX, which is a collaboration be- tween the Max Planck Institute for Radio Astronomy (MPIfR), the On- sala Space Observatory (OSO) and ESO, is the largest single-dish sub- millimetre telescope operating in the southern hemisphere and is based on a prototype antenna constructed for the ALMA project. O n a snowy scenario, SEPIA is lifted up and into the APEX instrument cabin. [ESO/Onsala Space Observatory/A. Ermakov] n