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Gigantic shock waves observable in the Universe

Shock wave Kappa Cassiopeia

 Automatic translation  Automatic translation Updated February 22, 2014

This shock wave (red bow on the image opposite) is in our Galaxy, the Milky Way. The shock wave caused by the displacement of a star can compress the gas into the space. When observing in the infrared, the environment of the star Kappa Cassiopeia that file at an impressive rate, we see this pressure in front of the star. Meet very high speed powered by the movement of the stars and gas into the galaxy gas creates the arc photographed by the Spitzer Space Telescope. Kappa Cassiopeia (κ Cas, κ Cassiopeia) or HD 2905 for astronomers , is a hot blue supergiant massive and that moves about 4 million km/h compared to its neighbors, or 1110 km/s. This bow shock around a star unveils high relative velocity. The passage of the star colors surrounding matter with a red glow. These structures are sometimes present in front of the fastest and most massive stars in the Milky Way.


These shocks form where the magnetic field and wind particles collide with gas and fugitive dust that fills interstellar space. The moving speed of our Sun is 217 m/s but the shock wave is substantially invisible to all light wave lengths. For cons, the rapid movement of Kappa Cassiopeia creates shocks that can be seen by Spitzer's infrared detectors. This shock wave that precedes the star has a radius of 4 light-years (1 al = 9 460 895 288 762 850 meters).

Image: Image of Shockwave Kappa Cassiopeia. The red arc of this infrared image taken by the Spitzer Space Telescope NASA is a giant shock wave created by the difference in speed of movement of the Kappa Cassiopeia star (the star at the center of the arc) relative to its neighbors.

 Onde de choc de kappa Cassiopée

Shock wave of the Tarantula


About 2400 massive stars are hidden in the center of the Tarantula Nebula (30 Doradus). These stars produce radiation so intense that the powerful winds blowing off the field. The gas of the nebula is heated to millions of degrees by stellar shock wave radiation. These shock waves are shown in blue on the X-ray image taken by the telescope Chandra X-ray Observatory. These shock waves are generated by winds and ultraviolet radiation from the young stars in the cluster. These explosions carve in the dust, huge blue bubbles of superheated gas from the cold material of the nebula. This cold material of orange color, is seen here in infrared emission with the Spitzer Space Telescope.


RMC 136, is the supercluster stars, located near the center of the Tarantula Nebula. It is known as 30 Doradus. The Tarantula Nebula is outside of our galaxy, in the Large Magellanic Cloud, 170 000 light-years from the solar system. At the heart of this star-forming region, 30 Doradus lies a huge cluster containing the largest stars, the most massive and hottest known to date.

Image: Image of the Tarantula nebula seen in X-ray telescope Chandra X-ray and infrared by the Spitzer Space Telescope. Image Credit: NASA

 Shock wave of the Tarantula

Shock wave of the Cartweel galaxy


The Cartwheel Galaxy (also known as the ESO 350-40) is a lenticular galaxy or annular located about 500 million light years away in the constellation Sculptor in the southern hemisphere. The cartwheel shape of this galaxy is the result of a violent galactic collision that occurred there are about 200 million years.
A small galaxy passed through the heart of a large disk galaxy, and produced this gigantic shock wave, which propagated the surrounding gas and dust in the galaxy, much like the ripples of water produced when a stone is thrown into a lake.
The Cartwheel galaxy is now surrounded by a bluish ring of 150 000 light years in diameter, composed of bright young stars. Moving at high speed of the shock wave, a compressed gas and dust, which has fostered the birth of stars that light up now, the edge of the wave. In the image, regions of star formation are shown in blue. The outer ring of the galaxy, is 1.5 times the size of our Milky Way. It can be seen in this picture, the galaxy is now back as a normal spiral galaxy, with galactic arms that form again from the central core.


This galaxy was a galaxy similar to the Milky Way, before it undergoes the collision. This is a celestial object of the most remarkable class of ring galaxies. Star formation in the rings, like the Cartwheel Galaxy, promotes the formation of stars of large size and very bright. When these massive stars explode as a supernova, it remains in their hearts, a neutron star or black hole. Some of these neutron stars and black holes attract matter from nearby stars and become powerful sources of X-rays Cartwheel contains an unusually high number of these black holes X-ray sources, because many massive stars have formed in the ring of the galaxy.
This image was produced with data from Hubble and adjusted using the open source software FITS Liberator 3, which was developed at ST-ECF. Judicious use of this tool has allowed the original Hubble observations, to obtain details of the Cartwheel galaxy.

NB: Hubble images of high resolution (ESA).

 shock wave cartwheel galaxy

Image: The image retired of this cosmic event, shows the Cartwheel galaxy also known as the ESO 350-40. Image Hubble telescope NASA / ESA Space.

Shock wave of the Bullet cluster


Clusters of galaxies are not formed, than to galaxies, they bathe in cold low density gas (1000 particles/m3) and in the extremely hot gas (10 to 100 million degrees). At these temperatures, the gas is fully ionized, it is a visible plasma in the field of x-rays. The gas is distributed in a way, much more diffuse, it fills the space between the galaxies and extends well beyond. The mass of gas belonging to the galaxy is much larger than the mass of the galaxy itself. If we measure the gravitational dynamics of the universe at large scale, the mass of ordinary matter in the observable universe is only 4% of the total mass. 23% of the mass is dark matter and 73% of dark energy. This is described in a predominantly accepted model, the SCDM model (Standard Cold Dark Matter). What we see when we look at the light of stars, galaxies and clusters is ordinary matter.
But how can we see dark matter?
Clusters of galaxies are the largest observable structures of matter. They consist of hundreds of galaxies bound together by their own gravitational attraction. Ordinary matter of galaxies is mainly gas, because the mass of the gas is much larger than the total mass of stars. All matter, ordinary matter and dark matter undergoes gravitational forces. It is in the Bullet cluster, that the cosmologists could "see" dark matter. The Bullet cluster or 1E 0657-56 (Bullet cluster) observable in the constellation Carina, is the result of the collision of two clusters of galaxies that happened there 150 million years. The study of this collision began in August 2006 and showed one of the strongest proofs of the existence of dark matter. When clusters or galaxies collide, the matter (stars, gas and dust) is perturbed by the gravitational forces. In reality, heavy objects like stars do not collide, they pass, one next to the other without ever meeting, because the space between the stars is immense. The stars are therefore not affected by the collision, they can be accelerated or slowed slightly gravitationally but not destroyed. By cons during the collision, the cold and hot gases that constitute the bulk of the baryonic mass of galaxies, will interact with each other, they will even be strongly and quickly slowed. They will mix more easily because of their atomic freedom and their very weak bond.


This is what we see on the composite image below cons. This gigantic collision between two clusters generated considerable energy, perhaps the most powerful of the universe since Big Bang. It is in the domain of X-rays, the observation of the collision sheds new light on dark matter, because the stars, gas and dark matter behave differently during the collision.
Galaxies of two clusters of galaxies are observed in visible light, it is the white spots, the hot gases of the two clusters are observed in X-rays, which are the red clouds, dark matter is shown in blue.
But what do we see exactly?
We see the result of a collision between two clusters. In this picture there are hundreds of galaxies grouped together in clusters but mostly we see a small cluster of galaxies in the blue right spot and a large cluster of galaxies in the blue spot on the left. Both gaseous envelopes of the two clusters are in red color, small red spot follows the little blue spot and the great red spot follows the big blue spot. In fact the small cluster of galaxies right, just cross the great cluster left. The huge collision "disheveled" two clusters of their halo gas causing a shock wave visible in the tip of the little red spot. This shock wave strongly compressed and therefore heated the gas in the cluster to the point to reach 100 million degrees. The cluster of the bullet is one of the hottest clusters known. In places the telescope Chandra X-ray Observatory has measured a speed of gas 4500 km / s.
The two clusters are now separated by 3.4 light years and the total mass calculated according to their speed and distance, represent much more than the mass of the visible ordinary matter (galaxies seen in the optical and gas seen in the X-rays). These are deliberately colored blue areas that show the distribution of the invisible dark matter in the cluster. In the frontal impact colossal, dark matter behaved like ordinary matter, it did not interact, it crossed another dark matter smoothly while the interstellar gas was snatched of the clusters. This caused the shock wave that can be seen in the red bullet-shaped cloud of gas right. The clear separation of dark matter and gas clouds is considered as direct evidence of the existence of dark matter.

 Bullet cluster and of dark matter

Image: What do we see in this false-color composite image?
We see all the matter in the cluster of the bullet "bullet cluster." Located 3.4 light years away from each other, the two clusters of individual galaxies Bullet are in the blue area and the two galactic gas clouds are seen in X-rays, in red). The blue colored areas represent the bulk of the mass of clusters, i.e. dark matter, six times more massive than ordinary matter. The cluster of the bullet is the smaller of the two cluster that crossing through the other side to the other. The huge collision "disheveled" two cluster of their halo gas causing a shock wave visible in the tip of the little red spot. This shock wave strongly compressed and therefore heated the gas in the cluster to the point to reach 100 million degrees. It stands out as a bullet followed by his trail of gas.
Credit: X-ray: NASA/CXC/CfA/ M.Markevitch et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/ D.Clowe et al. Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.;

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