Where are all the dwarfs?

Feb 01, 2013
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 and voids, known as the Cosmic Web. 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 .

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 galaxies and their low-mass neighbours - within their observed large scale environment", said Stefan Gottlöber of the Leibniz Institute for Astrophysics Potsdam.

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

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.

Zoom into the region where the dwarf is located. Credit: Alejandro Benítez Llambay

"These dwarfs move so fast that even the weakest membranes of the 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 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.

Explore further: Quest for extraterrestrial life not over, experts say

More information: Benítez-Llambay, A. et al. Dwarf galaxies and the Cosmic Web, Astrophysical Letters. doi:10.1088/2041-8205/763/2/L41

add to favorites email to friend print save as pdf

Related Stories

Cosmic Dance Helps Galaxies Lose Weight

Jul 29, 2009

(PhysOrg.com) -- A study published this week in the journal Nature offers an explanation for the origin of dwarf spheroidal galaxies. The research may settle an outstanding puzzle in unders ...

Hubble telescope unmasks ghost galaxies

Jul 10, 2012

(Phys.org) -- Astronomers have used Hubble Space Telescope to study some of the smallest and faintest galaxies in our cosmic neighbourhood. These galaxies are fossils of the early Universe: they have barely ...

Dark matter mystery deepens

Oct 17, 2011

(PhysOrg.com) -- Like all galaxies, our Milky Way is home to a strange substance called dark matter. Dark matter is invisible, betraying its presence only through its gravitational pull. Without dark matter ...

Cosmic thread that binds us revealed

Sep 29, 2011

(PhysOrg.com) -- Astronomers at The Australian National University have found evidence for the textile that forms the fabric of the Universe.

Recommended for you

Quest for extraterrestrial life not over, experts say

Apr 18, 2014

The discovery of an Earth-sized planet in the "habitable" zone of a distant star, though exciting, is still a long way from pointing to the existence of extraterrestrial life, experts said Friday. ...

Continents may be a key feature of Super-Earths

Apr 18, 2014

Huge Earth-like planets that have both continents and oceans may be better at harboring extraterrestrial life than those that are water-only worlds. A new study gives hope for the possibility that many super-Earth ...

Exoplanets soon to gleam in the eye of NESSI

Apr 18, 2014

(Phys.org) —The New Mexico Exoplanet Spectroscopic Survey Instrument (NESSI) will soon get its first "taste" of exoplanets, helping astronomers decipher their chemical composition. Exoplanets are planets ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

theon
2.3 / 5 (3) Feb 02, 2013
Of the predicted 10,000 dark dwarfs, none has been discovered. Those that do exist, appear to lie in a plane. This questions the credibility of the model.
yash17
2.3 / 5 (3) Feb 02, 2013
"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."

1."Cosmic web" may not homogeneous through the cosmos.
2. The massive supercomputers may not smart enough.

More news stories

Easter morning delivery for space station

Space station astronauts got a special Easter treat: a cargo ship full of supplies. The shipment arrived Sunday morning via the SpaceX company's Dragon cargo capsule.

Growing app industry has developers racing to keep up

Smartphone application developers say they are challenged by the glut of apps as well as the need to update their software to keep up with evolving phone technology, making creative pricing strategies essential to finding ...

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.