Over the lifetime of the cosmos galaxies have put on a great deal of weight but their food, and eating habits, are still mysterious. A new survey of carefully selected galaxies has focussed on their teenage years — roughly the period from about 3 to 5 billion years after the Big Bang.
This deep view of a tiny patch of sky in the constellation of Cetus (the Sea Monster) shows a selection of galaxies, marked with red crosses, that were used in a new survey of the feeding habits of young galaxies as they grew through cosmic time. Each of the tiny blobs, galaxies seen as they were between three and five billion years after the Big Bang, has been studied in detail using ESO's VLT and the SINFONI instrument.
By employing the state-of-the-art instruments on ESO's Very Large Telescope an international team is unravelling what really happened. In more than one hundred hours of observations the team has collected the biggest ever set of detailed observations of gas-rich galaxies at this early stage of their development .
"Two different ways of growing galaxies are competing: violent merging events when larger galaxies eat smaller ones, or a smoother and continuous flow of gas onto galaxies. Both can lead to lots of new stars being created," explains Thierry Contini (IRAP, Toulouse, France), who leads the work.
The new results point toward a big change in the cosmic evolution of galaxies, when the Universe was between 3 and 5 billion years old. Smooth gas flow (eso1040) seems to have been a big factor in the building of galaxies in the very young Universe, whereas mergers became more important later.
"To understand how galaxies grew and evolved we need to look at them in the greatest possible detail. The SINFONI instrument on ESO's VLT is one of the most powerful tools in the world to dissect young and distant galaxies. It plays the same role that a microscope does for a biologist," adds Thierry Contini.
Distant galaxies like the ones in the survey are just tiny faint blobs in the sky, but the high image quality from the VLT used with the SINFONI instrument  means that the astronomers can make maps of how different parts of the galaxies are moving and what they are made of. There were some surprises.
"For me, the biggest surprise was the discovery of many galaxies with no rotation of their gas. Such galaxies are not observed in the nearby Universe. None of the current theories predict these objects," says Benoit Epinat, another member of the team.
"We also didn't expect that so many of the young galaxies in the survey would have heavier elements concentrated in their outer parts — this is the exact opposite of what we see in galaxies today," adds Thierry Contini.
The team are only just starting to explore their rich set of observations. They plan to also observe the galaxies with future instruments on the VLT as well as using ALMA to study the cold gas in these galaxies. Looking further into the future the European Extremely Large Telescope will be ideally equipped to extend this type of study deeper into the early Universe.
 The name of the survey is MASSIV: Mass Assembly Survey with SINFONI in VVDS. The VVDS is the VIMOS-VLT Deep Survey. VIMOS is the VIsible imaging Multi-Object Spectrograph, a powerful camera and spectrograph on the VLT that was used to find the galaxies used in the MASSIV work, and measure their distances and other properties.
 SINFONI is the Spectrograph for INtegral Field Observations in the Near Infrared. It is the instrument on the VLT that was used for the MASSIV survey. SINFONI is a near-infrared (1.1-2.45 µm) integral field spectrograph using adaptive optics to improve the image quality.
This research was presented in four papers describing the MASSIV survey that will appear in the journal Astronomy & Astrophysics.
The team is composed of T. Contini (Institut de Recherche en Astrophysique et Planetologie [IRAP], CNRS & Universite de Toulouse, France), B. Epinat (Laboratoire d'Astrophysique de Marseille, CNRS & Universite d'Aix-Marseille, France [LAM]), D. Vergani (Istituto di Astrofisica Spaziale e Fisica Cosmica-INAF, Bologna, Italy [IASF BO-INAF]), J. Queyrel (IRAP), L. Tasca (LAM), B. Garilli (Istituto di Astrofisica Spaziale e Fisica Cosmica-INAF, Milan, Italy [IASF MI-INAF]), O. Le Fevre (LAM), M. Kissler-Patig (ESO), P. Amram (LAM), J. Moultaka (IRAP), L. Paioro (IASF MI-INAF), L. Tresse (LAM), C. Lopez-Sanjuan (LAM), E. Perez-Montero (Instituto de Astrofisica de Andalucia, Granada, Spain), C. Divoy (IRAP) and V. Perret (LAM).
The year 2012 marks the 50th anniversary of the founding of the European Southern Observatory (ESO). ESO is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world's largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".
- Research papers in A&A: Paper I, Paper II, Paper III, Paper IV
- MASSIV website: http://www.eso.org/ http://www.ast.obs-mip.fr/users/contini/MASSIV/
- Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/
- Article about MASSIV in ESO Messenger: http://www.eso.org/public/archives/releases/sciencepapers/eso1212/eso1212e.pdf
Richard Hook | EurekAlert!
First evidence on the source of extragalactic particles
13.07.2018 | Technische Universität München
Simpler interferometer can fine tune even the quickest pulses of light
12.07.2018 | University of Rochester
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
13.07.2018 | Event News
13.07.2018 | Materials Sciences
13.07.2018 | Life Sciences