9 February 2016
SA astronomers help discover hidden galaxies behind Milky Way
UCT Professor Renée Kraan-Korteweg and Dr Anja Schröder of SAAO among lead authors of breakthrough paper
Hi-res images and animations available from http://www.icrar.org/hidden-galaxies
An international team of scientists that includes a leading astronomy researcher from the University of Cape Town and one from the South African Astronomical Observatory (SAAO) have helped to make a groundbreaking discovery by peering through the stars and dust of the Milky Way with a radio telescope to discover hidden galaxies beyond. Both are available for interview.The study involved researchers from Australia, South Africa, the USA and the Netherlands.
Professor Kraan-Korteweg, who is internationally recognised as leader in unveiling the galaxy and mass distribution behind the Plane of the Milky Way, said astronomers have been trying to map the galaxy distribution hidden behind the Milky Way for decades. It has been a focus of her research over the last 25 years, and she has involved numerous students (notably at UCT) in this type of research. She said: “We’ve used a range of techniques, including telescopes at the SAAO, but only radio observations have really succeeded in allowing us to see through the thickest foreground layer of dust and stars in the inner Milky Way. An average galaxy contains 100 billion stars, so finding hundreds of new galaxies hidden behind the Milky Way points to a lot of mass we didn’t know about until now.” Professor Kraan-Korteweg mentions that such s ystematic surveys with radio telescopes are in a sense precursors to the much deeper surveys for neutral gas planned with the Square Kilometre Array precursors, such as MeerKAT.
Both Professor Kraan-Korteweg and Dr Schröder have been involved in this project since its inception in 1997. This included regular observing runs over many years with the Parkes Radio Telescope in Australia, data reduction, the actual search for signatures of the galaxies in the data, and presenting preliminary results at international conferences. Both were in charge of preparing major parts of the paper and are working on follow-up analysis, in particular using near-infrared data obtained with the SAAO IRSF (Infrared Survey Facility) using the motions of the detected galaxies to get better estimates of the overall mass density in the nearby Universe.
Original publication details:
‘The Parkes HI Zone of Avoidance Survey’, published in the Astronomical Journal February 9th, 2015. Available from http://bit.ly/1nHeAwR