Cosmic Web Stripping, Visualization
Credits: Alejandro Benitez Llambay
Astronomers of the international CLUES collaboration have identified
“Cosmic Web Stripping” as a new way of explaining the famous missing
dwarf problem: the lack of observed dwarf galaxies compared with that
predicted by the theory of Cold Dark Matter and Dark Energy.
High-precision observations over the last two decades have indicated
that our Universe consists of about 75% Dark Energy, 20% Dark Matter and
5% ordinary matter. Galaxies and matter in the universe clump in an
intricate network of filaments and voids, known as the Cosmic Web.
Computer experiments on massive supercomputers have shown that in such a
Universe a huge number of small “dwarf” galaxies weighing just one
thousandth of the Milky Way should have formed in our cosmic
neighbourhood. Yet only a handful of these galaxies are observed
orbiting around the Milky Way. The observed scarcity of dwarf galaxies
is a major challenge to our understanding of galaxy formation.
An international team of researchers has studied this issue within
the Constrained Local Universe Simulations project (CLUES). The CLUES
simulations use the observed positions and peculiar velocities of
galaxies within Tens of Millions of light years of the Milky Way to
accurately simulate the local environment of the Milky Way. “The main
goal of this project is to simulate the evolution of the Local Group -
the Andromeda and Milky Way galaxies and their low-mass neighbours -
within their observed large scale environment”, said Stefan Gottlöber of
the Leibniz Institute for Astrophysics Potsdam.
Analysing the CLUES simulations, the astronomers have now found that
some of the far-out dwarf galaxies in the Local Group move with such
high velocities with respect to the Cosmic Web that most of their gas
can be stripped and effectively removed. They call this mechanism
“Cosmic Web Stripping”, since it is the pancake and filamentary
structure of the cosmos that is responsible for depleting the dwarfs’
gas supply.
“These dwarfs move so fast that even the weakest membranes of the
Cosmic Web can rip off their gas”, explained Alejandro Benítez LLambay,
PhD student at the Instituto de Astronomía Teórica y Experimental of
the Universidad Nacional de Córdoba in Argentina, and first author of
the publication of this study. Without a large gas reservoir out of
which to form stars, these dwarf galaxies should be so small and dim
that they would be hardly be visible today. The missing dwarfs may
simply be too faint to see.
The study of Benítez Llambay and colleagues is published in the February issue of Astrophysical Letters.
CWS1 and CWS2
Images / Movies
(1) www.clues-project.org/movies/cosmicwebstripping.html
(2) www.aip.de/en/news/press/cws1
(3) www.aip.de/en/news/press/cws2
Movies (1): see website for description
Image (2): Cosmic Web Stripping removes gas from a very fast dwarf
galaxy crossing the local web. The image is a visualization of a CLUES
simulation. The arrow symbolizes the velocity oft he dwarf, located
right below (Credits: Alejandro Benítez Llambay)
Image (3): Zoom into the region where the dwarf is located (Credits: Alejandro Benítez Llambay)
Constrained Local UniversE Simulations - www.clues-project.org
Publication
Alejandro Benítez-Llambay, Julio F. Navarro, Mario G. Abadi, Stefan
Gottlöber, Gustavo Yepes, Yehuda Hoffman, and Matthias Steinmetz: Dwarf
galaxies and the Cosmic Web, doi:10.1088/2041-8205/763/2/L41
The key areas of research at the Leibniz Institute for Astrophysics
Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics.
A considerable part of the institute's efforts aim at the development
of research technology in the fields of spectroscopy, robotic
telescopes, and e-science. The AIP is the successor of the Berlin
Observatory founded in 1700 and of the Astrophysical Observatory of
Potsdam founded in 1874. The latter was the world's first observatory to
emphasize explicitly the research area of astrophysics. The AIP has
been a member of the Leibniz Association since 1992.
