ALMA discovers dew drops surrounding dusty spider’s web
Last Updated on Friday, 01 July 2016 11:13
Published on Friday, 01 July 2016 11:11
Astronomers have spotted glowing droplets of condensed water in the distant Spiderweb Galaxy – but not where they expected to find them. Detections with the Atacama Large Millimeter/submillimeter Array (ALMA) show that the water is located far out in the galaxy and therefore cannot be associated with central, dusty, star-forming regions, as previously thought. The results will be presented at the National Astronomy Meeting 2016 in Nottingham by Dr Bitten Gullberg on Friday 1st July.
“Observations of light emitted by water and by dust often go hand-in-hand. We usually interpret them as an insight into star-forming regions, with the illumination from young stars warming dust particles and water molecules until they start to glow. Now, thanks to the power of ALMA, we can -- for the first time -- separate out the emissions from the dust and water populations, and pinpoint their exact origins in the galaxy. The results are quite unexpected in that we’ve found that the water is located nowhere near the dusty stellar nurseries,” explained Dr Gullberg, of the Centre for Extragalactic Astronomy, Durham University, UK.
The Spiderweb Galaxy is one of the most massive galaxies known. It lies 10 billion light-years away and is made up of dozens of star-forming galaxies in the process of merging together. The ALMA observations show that the light from the dust originates in the Spiderweb Galaxy itself. However, the light from the water is concentrated in two regions far to the east and west of the galaxy core.
Gullberg and her colleagues believe that the explanation lies with powerful jets of radio waves that are ejected from a supermassive black hole at the centre of the Spiderweb Galaxy. The radio jets compress clouds of gas along their path and heat up water molecules contained within the clouds until they emit radiation.
“Our results show how important it is to pinpoint the exact locations and origins for light in galaxies. We may also have new clues to the processes that trigger star formation in interstellar clouds,” said Gullberg. “Stars are born out of cold, dense molecular gas. The regions in the Spiderweb where we’ve detected water are currently too hot for stars to form. But the interaction with the radio jets changes the composition of the gas clouds. When the molecules have cooled down again, it will be possible for the seeds of new stars to form. These “dew drop” regions could become the next stellar nurseries in this massive, complex galaxy.”
Dr Robert Massey
Royal Astronomical Society
Mob: +44 (0)7802 877 699
Ms Anita Heward
Royal Astronomical Society
Mob: +44 (0)7756 034 243
Dr Bitten Gullberg
Centre for Extragalactic Astronomy
The Spiderweb Galaxy as seen by the Hubble Space Telescope (optical) in red, the Very Large Array (radio) in green and the Atacama Large Millimeter/submillimeter Array (sub-millimetre) in blue. The red colour shows where the stars are located within this system of galaxies. The radio jet is shown in green, and the position of the dust and water are seen in blue. The water is located to the left and right of the central galaxy. The water to the right is at the position where the radio jet bends down wards. The dust is also seen in blue. The dust is located at the central galaxy and in smaller companion galaxies in its surroundings. Credit: NASA/ESA/HST/STScI/NRAO/ESO/
Annotated image: http://nam2016.org/images/nam2016/Media/Gullberg/Spider.jpg
Unannotated image: http://nam2016.org/images/nam2016/Media/Gullberg/Spider2.jpg
ALMA Finds Dew Drops in the Dusty Spider’s Web, Bitten Gullberg et al, February 2016, Astronomy & Astrophysics: http://arxiv.org/pdf/1602.04823v1.pdf
Notes for editors
The RAS National Astronomy Meeting 2016 (NAM 2016, http://nam2016.org) 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 and the University of Nottingham. Follow the conference on Twitter via @rasnam2016
The University of Nottingham (http://nottingham.ac.uk/) 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, http://www.stfc.ac.uk) 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 via @stfc_matters
The Royal Astronomical Society (RAS, http://www.ras.org.uk), 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 via @royalastrosoc
About Durham University
- A world top 100 university with a global reputation and performance in research and education
- Ranked 61 globally in the QS World University Rankings 2015/16
- Ranked 31 globally for the employability of its students by blue-chip companies world-wide (QS World University Rankings 2015/16)
- Ranked 70 globally in the THE World University Rankings 2015/16
- In the global top 50 for Arts and Humanities (THE World University Rankings 2014/15)
- A member of the Russell Group of leading research-intensive UK universities
- Research at Durham shapes local, national and international agendas, and directly informs the teaching of our students
- In the 2016 Times and Sunday Times Good University Guide and the 2016 Complete University Guide, Durham was ranked fifth in the UK.
- Durham was named as The Times and Sunday Times 'Sports University of the Year 2015' in recognition of outstanding performance in both the research and teaching of sport, and student and community participation in sport at all levels.