Una visión diferente para disfrutar de la magia del Universo
Astronomía - Cosmología - Astrofotografía - Astrofísica - Exploración Espacial

💫Nuevo!! Universo Mágico muestra los catálogos astronómicos más populares. Búscalos en la barra superior de navegación y lateral.

💫Los aficionados ya pueden escribir sobre astronomía. Date de alta como Autor en Universo Mágico Público.

 ðŸ’«Si eres Autor prueba la opción Nueva Entrada

💫Grupos en Facebook: Astroimaging - Stars in the Sky - Astronomy Plus - Astrophotographers

💫Sky around galaxy cluster CL0024+1654

Communities & Groups:     (New)  Space World Google+        Big Bang Facebook



This is a 2.5-degree field around galaxy cluster CL0024+1654. The cluster galaxies are visible in the centre of the image in yellow. The image is a colour composite constructed from three Digitized Sky Survey 2 images: Blue (shown in blue), Red (shown in green), and Infrared (shown in red). Clusters of galaxies are the largest stable systems in the Universe. They are like laboratories for studying the relationship between the distributions of dark and visible matter. In 1937, Fritz Zwicky realised that the visible component of a cluster (the thousands of millions of stars in each of the thousands of galaxies) represents only a tiny fraction of the total mass. About 80-85% of the matter is invisible, the so-called 'dark matter'. Although astronomers have known about the presence of dark matter for many decades, finding a technique to view its distribution is a much more recent development. Led by Drs Jean-Paul Kneib (from the Observatoire Midi-Pyrénées, France/Caltech, United States), Richard Ellis and Tommaso Treu (both Caltech, United States), the team used the NASA/ESA Hubble Space Telescope to reconstruct a unique 'mass map' of the galaxy cluster CL0024+1654. It enabled them to see for the first time on such large scales how mysterious dark matter is distributed with respect to galaxies. This comparison gives new clues on how such large clusters assemble and which role dark matter plays in cosmic evolution. Tracing dark matter is not an easy task because it does not shine. To make a map, astronomers must focus on much fainter, more distant galaxies behind the cluster.



The shapes of these distant systems are distorted by the gravity of the foreground cluster. This distortion provides a measure of the cluster mass, a phenomenon known as "weak gravitational lensing". To map the dark matter of CL0024+1654, more than 120 hours observing time was dedicated to the team. This is the largest amount of Hubble time ever devoted to studying a galaxy cluster. Despite its distance of 4.5 thousand million light-years (about one third of the look-back time to the Big Bang) from Earth, this massive cluster is wide enough to equal the angular size of the full Moon. To make a mass map that covers the entire cluster required observations that probed 39 regions of the galaxy cluster. The investigation has resulted in the most comprehensive study of the distribution of dark matter in a galaxy cluster so far and extends more than 20 million light-years from its centre, much further than previous investigations. Many groups of researchers have tried to perform these types of measurements with ground-based telescopes. However, the technique relies heavily on finding the exact shapes of distant galaxies behind the cluster. The sharp vision of a space telescope such as NASA-ESA's Hubble is superior. The study reveals that the density of dark matter on large scales drops sharply with distance from the cluster centre. This confirms a picture that has emerged from recent detailed computer simulations.

As Richard Ellis says: 'Although theorists have predicted the form of dark matter in galaxy clusters from numerical simulations based on the effects of gravity alone, this is the first time we have convincing observations to back them up. Some astronomers had speculated clusters might contain large reservoirs of dark matter in their outermost regions. Assuming our cluster is representative, this is not the case.' The team noticed that dark matter appears to clump together in their map. For example, they found concentrations of dark matter associated with galaxies known to be slowly falling into the system. Generally, the researchers found that the dark matter traces the cluster galaxies remarkably well and over an unprecedented range of physical scales. 'When a cluster is being assembled, the dark matter will be smeared out between the galaxies where it acts like a glue,' says Jean-Paul Kneib. 'The overall association of dark matter and 'glowing matter' is very convincing evidence that structures like CL0024+1654 grow by merging of smaller groups of galaxies that were already bound by their own dark matter components.' Future investigations using Hubble's new camera, the Advanced Camera for Surveys (ACS), will extend this work when Hubble is trained on a second galaxy cluster later this year. ACS is 10 times more efficient than the Wide Field and Planetary Camera 2 used for this investigation, making it possible to study finer mass clumps in galaxy clusters and help work out how the clusters are assembled.

Credit: European Space Agency, NASA, Jean-Paul Kneib (Observatoire Midi-Pyrénées, France / Caltech, USA) and the Digitized Sky Survey


Communities & Groups:     (New)  Space World Google+        Big Bang Facebook

Publicar un comentario






Para visualizar correctamente este sitio web utiliza un navegador basado en Chromium, o Fire Fox. Si te gusta la privacidad se recomienda utilizar Tor Browser.
Para la correcta visualización de la página de Husos Horarios utiliza Internet Explorer.

universo cosmos espacio astonomía cosmología exploración espacial astrofotografía astrofotógrafo astrónomo cosmólogo nebulosa galaxia nube oscura brillante estrella estrellas cúmulo estelar abierto globular planeta sol mercurio venus tierra marte júpiter saturno urano neptuno plutón ceres fobos deimos luna titán encelado europa calisto ganímedes ío caronte hydra nix cometa asteroide cinturón grupo galáctico supercúmulo planetaria emisión reflexión absorción polvo gas atmósfera rayos X gamma cuásar púlsar herbig-haro constelación asterismo fugaces meteoros meteoritossatélite iss estación cohetetelescopio hubble chandra spitzer nustar xmm-newton most very vlt vla vst vista herschel soar ssro sloan rosetta rosat philae osiris subaru campanas kitt keck wilson observatorio palomar calar horizons voyager mpg mycron merlin maven express mariner magellan juno grand canarias gemini hawk galileo galex gaia fuse digited dawn clementine cassini apolo apex alma agujero agujeros polo norte sur sistema solar vacío local big bang oculta coronalunar solar cráter superluna sangre eclipse total parcial ocultación luminiscencia refracción destello anular tránsito protuberancia filamento mancha manchas solares andrómeda messier enana física físico ngc ic trío arp melotte doradus barnard pilares trompa burbuja nuro cabeza cisne cygnus sh2 shapley mz rho sagittarius tarántula magallanes gran pequeña triángulo pickering torre variable binaria espectroscópica bennu thule carinae cygnicom coma virgo cuarteto quinteto cadena energía color markarian tritón molecular supernova nova remanente explosión frente choque einstein caldwell darwin huygens ptolomeo halley piggot gillett hale riccioli gentil newton bode kepler dreyer harding copérnico lacaille loys pierre hawking ciencia científicos cielo arcoiris lenticular espiral elíptica barrada brazo brazos región regiones vdb rcw año luz parsec grado grados celsius farenheit kelvin minuto minutos arco arcominutos oculta llena oscura partículas átomo átomos temperatura millones miles luz espectro universe cosmos space astonomy cosmology space exploration astrophotography astrophotographer astronomer cosmologist nebula galaxy cloud dark shining star stars star cluster open globular planet sun mercury venus earth mars jupiter saturn uranus neptune pluto ceres fobos deimos moon titan waxed europe calist ganymede charontera hydra nix comet aste group hydra nix comet aste group hydra nix comet band galactic planetary supercluster emission reflection absorption dust gas atmosphere x-ray gamma quasar pulsar herbig-haro constellation asterism fleeting meteor meteorite satellite iss station rockettelescope hubble chandra spitzer nustar xmm-newton most very vlt vla vst view herschel soar ssro sloan rosetta rostar ketar keckar ketar ketar ketar subtle rosat ketar roster ketsar keta subar kitty wilson observatory pigeon jello horizons voyager mpg mycron merlin maven express mariner magellan juno grand canarias gemini hawk galileo galex gaia fuse digited dawn clementine cassini apollo apex soul hole aguj eros north pole south solar system empty local big bang hidden coronalunar solar crater supermoon blood eclipse total partial concealment luminescence refraction ring flash transit protuberance filament spot sunspots andromeda messier dwarf physical physics ngc ic trio arp melotte doradus barnard pillars trunk nuro head swan cygnus sh2 shapley mz rho sagittarius tarantula magallanes large small triangle pickering variable tower binary spectroscopic bennu thule carinae cygnicom coma virgo quartet quintet chain energy color markarian molecular triton supernova nova remnant explosion front shock shock einstein caldwell darwin huygens ptolomeo halley piggot gyerton keplentil dd gillett harder keterton gilton kepleton dilton graveyard copernicus lacaille loys pierre hawking science scientists sky rainbow lenticular spiral elliptic barred arm arms region regions vdb rcw year light parsec degree degrees celsius farenheit kelvin minute minutes arc minute arch hidden full dark particles atom atoms temperature millions thousand light spectrum