Using VIMOS on ESO's Very Large Telescope, a team of French and Italian astronomers have shown the strong influence the environment exerts on the way galaxies form and evolve. The scientists have for the first time charted remote parts of the Universe, showing that the distribution of galaxies has considerably evolved with time, depending on the galaxies' immediate surroundings. This surprising discovery poses new challenges for theories of the formation and evolution of galaxies.
The 'nature versus nurture' debate is a hot topic in human psychology. But astronomers too face similar conundrums, in particular when trying to solve a problem that goes to the very heart of cosmological theories: are the galaxies we see today simply the product of the primordial conditions in which they formed, or did experiences in the past change the path of their evolution?
In a large, three-year long survey carried out with VIMOS , the Visible Imager and Multi-Object Spectrograph on ESO's VLT, astronomers studied more than 6,500 galaxies over a wide range of distances to investigate how their properties vary over different timescales, in different environments and for varying galaxy luminosities . They were able to build an atlas of the Universe in three dimensions, going back more than 9 billion years.
This new census reveals a surprising result. The colour-density relation, that describes the relationship between the properties of a galaxy and its environment, was markedly different 7 billion years ago. The astronomers thus found that the galaxies' luminosity, their initial genetic properties, and the environments they reside in have a profound impact on their evolution.
"Our results indicate that environment is a key player in galaxy evolution, but there's no simple answer to the 'nature versus nurture' problem in galaxy evolution," said Olivier Le Fèvre from the Laboratoire d'Astrophysique de Marseille, France, who coordinates the VIMOS VLT Deep Survey team that made the discovery. "They suggest that galaxies as we see them today are the product of their inherent genetic information, evolved over time, as well as complex interactions with their environments, such as mergers."
Scientists have known for several decades that galaxies in the Universe's past look different to those in the present-day Universe, local to the Milky Way . Today, galaxies can be roughly classified as red, when few or no new stars are being born, or blue, where star formation is still ongoing. Moreover, a strong correlation exists between a galaxy's colour and the environment it resides in: the more sociable types found in dense clusters are more likely to be red than the more isolated ones.
By looking back at a wide range of galaxies of a variety of ages, the astronomers were aiming to study how this peculiar correlation has evolved over time.
"Using VIMOS, we were able to use the largest sample of galaxies currently available for this type of study, and because of the instrument's ability to study many objects at a time we obtained many more measurements than previously possible," said Angela Iovino, from the Brera Astronomical Observatory, Italy, another member of the team.
The team's discovery of a marked variation in the 'colour-density' relationship, depending on whether a galaxy is found in a cluster or alone, and on its luminosity, has many potential implications. The findings suggest for example that being located in a cluster quenches a galaxy's ability to form stars more quickly compared with those in isolation. Luminous galaxies also run out of star-forming material at an earlier time than fainter ones.
They conclude that the connection between galaxies' colour, luminosity and their local environment is not merely a result of primordial conditions 'imprinted' during their formation - but just as for humans, galaxies' relationship and interactions can have a profound impact on their evolution.
Henri Boffin | alfa
Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University
Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences