The Horny Astronaut

Intergalactic fascinations&oddities and guys who may or may not be naked with each other...

NSFW. 18+

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distant-traveller:

Where are all the dwarfs?

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 neighborhood. 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 10,000,000 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 neighbors — within their observed large scale environment”, said Stefan Gottlöber of the Leibniz Institute for Astrophysics Potsdam.
Analyzing 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. 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.

Image credits: Alejandro Benítez Llambay

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fuckyeahspaceexploration:

Earth photobombing the Moon

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spacettf:

Cosmic dust clouds in Messier 78 by European Southern Observatory on Flickr.
Via Flickr: This image of the region surrounding the reflection nebula Messier 78, just to the north of Orion’s belt, shows clouds of cosmic dust threaded through the nebula like a string of pearls. The submillimetre-wavelength observations, made with the Atacama Pathfinder Experiment (APEX) telescope and shown here in orange, use the heat glow of interstellar dust grains to show astronomers where new stars are being formed. They are overlaid on a view of the region in visible light. Credit: ESO/APEX (MPIfR/ESO/OSO)/T. Stanke et al./Igor Chekalin/Digitized Sky Survey 2

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astronomer-in-progress:

Abell 2052: A Galaxy Cluster Gets Sloshed
Image credit: NASA/Chandra X-ray Observatory

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pelagic-existence:

Holy butt.

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leviathan8:

Tycho’s Supernova Remnant

This new image of Tycho’s supernova remnant, dubbed Tycho for short, contains striking new evidence for what triggered the original supernova explosion, as seen from Earth in 1572. Tycho was formed by a Type Ia supernova, a category of stellar explosion used in measuring astronomical distances because of their reliable brightness.
Low and medium energy X-rays in red and green show expanding debris from the supernova explosion. High energy X-rays in blue reveal the blast wave, a shell of extremely energetic electrons. Also shown in the lower left region of Tycho is a blue arc of X-ray emission. Several lines of evidence support the conclusion that this arc is due to a shock wave created when a white dwarf exploded and blew material off the surface of a nearby companion star. Previously, studies with optical telescopes have revealed a star within the remnant that is moving much more quickly than its neighbors, hinting that it could be the companion to the supernova that was given a kick by the explosion.
Other details of the arc support the idea that it was blasted away from the companion star. For example, the X-ray emission of the remnant shows an apparent “shadow” next to the arc, consistent with the blocking of debris from the explosion by the expanding cone of material stripped from the companion. This shadow is most obvious in very high energy X-rays showing iron debris

Credit: NASA/CXC/Chinese Academy of Sciences/F. Lu et al

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