Space Team Discovers Universe is Self-Cleaning
An international team of astronomers today (29 June) released a gazetteer of the hidden universe, which reveals the unseen sources of energy found over the last 12 billion years of cosmic history. Professor Haley Gomez of Cardiff University presented this catalogue of the Universe’s hidden energy sources, made with the ESA Herschel Space Observatory, at the National Astronomy Meeting in Nottingham.
When the European Space Agency (ESA) Herschel Space Observatory launched in 2009 it meant that, for the first time, it was possible to track down this hidden energy. The missing light is re-emitted by the dust grains into far-infrared radiation, detected by the Herschel telescope. For the last seven years, an international team of over 100 astronomers has been analysing the images from the largest Herschel survey, named the Herschel Astrophysical Terahertz Large Area Survey (the Herschel ATLAS). Today sees the release of their first catalogues of the hidden universe.
The Herschel ATLAS discovered about half a million far-infrared sources. The size of the survey means that the survey contains both large numbers of nearby galaxies like our own, which can be detected with conventional optical telescopes, and very distant galaxies whose light has taken billions of years to reach us. The most distant galaxies in the survey are being seen as they were 12 billion years ago, only shortly after the Big Bang. They are so dusty that they are virtually impossible to detect with standard telescopes and are often gravitationally magnified by intervening galaxies. These early systems are the distant ancestors of galaxies like our own.
Dr Elisabetta Valiante, also of Cardiff University, and the lead author of one of the papers describing the catalogues, says: “The exciting thing about our survey is that it encompasses almost all of cosmic history, from the violent star-forming systems full of dust and gas in the early universe that are essentially galaxies in the process of formation, to the much more subdued systems we see around us today.”
The huge size of the survey has meant that, for the first time, it has also been possible to study the changes that have occurred in galaxies comparatively recently in cosmic history. The team has shown that even only one billion years in the past, a small fraction of the age of the universe, galaxies were forming stars faster and contained more dust than galaxies today.
According to Dr Nathan Bourne of the University of Edinburgh, and the lead author of the other paper describing the catalogues: “We were surprised to find that we didn’t need to look far in the past to see signs of galaxy evolution. Our results show that the reason for this evolution is that galaxies used to contain more dust and gas in the past, and the universe is gradually becoming cleaner as the dust is used up.”
The catalogues and maps of the hidden universe are a triumph for the Herschel team. They will be vital tools for astronomers trying to explore the history of galaxies and the wider cosmos.
Dr Loretta Dunne, another Cardiff University scientist, and co-leader of the project adds: “Before Herschel we only knew of a few hundred such dusty sources in the distant universe and we could only effectively 'see' them in black and white. Herschel, with its five filters, has given us the equivalent of technicolour, and the colours of the galaxies tell us about their distances and temperatures. So now we have half a million galaxies we can use to map out the hidden star formation in the universe.”
The H-ATLAS survey is a core part of the EU Research Executive Agency programme the Herschel Extragalactic Project (HELP). HELP brings together H-ATLAS and other extragalactic surveys carried out by Herschel, and combines these with major surveys by other observatories to provide a lasting legacy from the Herschel mission. This data release from the H-ATLAS team is coordinated with data releases this week from the HELP team and the Herschel Multi-tiered Extragalactic Survey (HerMES). Prof Seb Oliver of the University of Sussex leads HELP and HerMES. He says: “It is fantastic to see these high quality data products emerge from H-ATLAS, I have no doubt that astronomers will be using these for decades to come”.
Göran Pilbratt, the Herschel Project Scientist adds: “Although Herschel made its last observation in 2013, current and future generations of astronomers will find the H-ATLAS maps and catalogues essential for finding their way around the hidden universe.”
Dr Robert Massey
Ms Anita Heward
NAM 2016 press office
An ISDN line and a Globelynx fixed camera are available for radio and TV interviews. To request these, please contact Robert or Anita.
Dr Nathan Bourne
Dr Loretta Dunne (co-Principal Investigator of the Herschel-ATLAS)
Prof Haley Gomez
Dr Elisabetta Valiante
Prof Steve Eales (co-Principal Investigator of the Herschel ATLAS)
Dr Goran Pilbratt (Project Scientist of the Herschel Space Observatory)
Images and captions
The new work will appear in papers by Bourne, N. et al. 2016, and Valiante, E. et al. 2016, both submitted to Monthly Notices of the Royal Astronomical Society.
Notes for editors
The RAS National Astronomy Meeting 2016 (NAM 2016) takes place this year at the University of Nottingham from 27 June to 1 July. NAM 2016 brings together more than 500 space scientists and astronomers to discuss the latest research in their respective fields. The conference is principally sponsored by the Royal Astronomical Society, the Science and Technology Facilities Council. Follow the conference on Twitter
The University of Nottingham has 43,000 students and is ‘the nearest Britain has to a truly global university, with a “distinct” approach to internationalisation, which rests on those full-scale campuses in China and Malaysia, as well as a large presence in its home city.’ (Times Good University Guide 2016). It is also one of the most popular universities in the UK among graduate employers and the winner of ‘Outstanding Support for Early Career Researchers’ at the Times Higher Education Awards 2015. It is ranked in the world’s top 75 by the QS World University Rankings 2015/16, and 8th in the UK by research power according to the Research Excellence Framework 2014. It has been voted the world’s greenest campus for four years running, according to Greenmetrics Ranking of World Universities.
Impact: The Nottingham Campaign, its biggest-ever fundraising campaign, is delivering the University’s vision to change lives, tackle global issues and shape the future.
The Science and Technology Facilities Council (STFC) is keeping the UK at the forefront of international science and has a broad science portfolio and works with the academic and industrial communities to share its expertise in materials science, space and ground-based astronomy technologies, laser science, microelectronics, wafer scale manufacturing, particle and nuclear physics, alternative energy production, radio communications and radar. STFC's Astronomy and Space Science programme provides support for a wide range of facilities, research groups and individuals in order to investigate some of the highest priority questions in astrophysics, cosmology and solar system science. STFC's astronomy and space science programme is delivered through grant funding for research activities, and also through support of technical activities at STFC's UK Astronomy Technology Centre and RAL Space at the Rutherford Appleton Laboratory. STFC also supports UK astronomy through the international European Southern Observatory. Follow STFC on Twitter.
This research has been funded by grants from the Science and Technology Facilities Council and the Cosmicdust, Cosmicism, Herschel Legacy Program projects funded by the European Union.
The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organizes scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.
The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.
Follow the RAS on Twitter