First observations made with deep-space water-hunting instrument
A team of astronomershas made the first observations with a cutting-edge water-huntinginstrument. The instrument, known as the Swedish–ESO PI receiverfor APEX (SEPIA), is not only suited for identifying signatures ofwater and other molecules in the Milky Way but also in othergalaxies, and it may even be capable of detecting ancient waterdating back to the early Universe.
SEPIA is in essence ahighly-sensitive spectrograph calibrated to search for a particularlight wavelength (between 1.4 – 1.9 mm) that indicates the presenceof water. Mounted aboard the Atacama Pathfinder Experiment (APEX)telescope, the delicate sensors must be cooled to a temperature onlyslightly above absolute zero in order to function optimally.
Ordinarily, instrumentslike SEPIA would have to cope with the vast quantities of water vaporpresent in Earth's dense atmosphere, making terrestrial-based waterhunting an unattractive option. However, the location of APEX high inthe incredibly dry Chajnantor Plateau in Chile renders theobservatory unaffected by the detrimental effects of our planet'satmosphere, allowing the telescope to gaze into the cosmosunhindered.
It is well known thatthe presence of water is necessary for the creation of life, and it is hopedthat the search for water in the greater cosmos will inform currenttheories on the importance of water in our Milky Way, and likelihoodof extraterrestrial life in our Universe.
Initial observationsvalidated the sensors, demonstrating that the instrument was ready toenter its operational life. Following the testing, suggestions forthe use of SEPIA have been opened up to the global scientificcommunity.
"The firstmeasurements with SEPIA on APEX show that we really are opening up anew window, including looking at water in interstellar space —SEPIA will give astronomers a chance to search for objects that canbe followed up at higher spatial resolution when the same receiverbecomes operational on the ALMA array," says John Conway,director of Onsala Space Observatory, Chalmers University ofTechnology, Sweden.