Confirmed slight distortion of gravity lens by dark matter filament connecting clusters of galaxies

ByNASA Goddard Photo and Video

Just the other day, CERNDiscover new particles seen as Higgs particlesWe accomplished a major discovery that, on July 4th academic journal Nature, this is also definitely a big discovery, filamentary dark matter (Dark matter filament) Has actually been confirmed in the publication of the paper has been published.

By the way, the top image is the Andromeda galaxy taken by NASA.

A filament of dark matter between two clusters of galaxies: Nature: Nature Publishing Group

Dark Matter Filament Between Galaxy Clusters Found | Space.com

Dark matter is the thread connecting galaxy clusters | Ars Technica

The solar systemMilky Way (Milky Way Galaxy)It is located in the Orion arm of Galaxy Railway 999 as the other galaxy, closest to the Milky Way GalaxyAndromeda galaxyAnd "Space Battleship Yamato"Large Magellan galaxy (Large Magellan Nebula)And others are known. These celestial bodies in hundreds to thousands, gravitatively constrained objectsClusters of galaxiesI call it.

There are two clusters of galaxies "Abel 222" and "Abel 223" at a distance of 2.7 billion light years from the earth, but during this timeThere is a filamentary dark matter (dark matter filament)It was confirmed by teams of Journal Dietrich, astronomer at the University of Munich Observatory. The theory itself that "dark matter filament exists" has been told as a theory,This was the first time that was actually confirmed.


On the upper side of the photo is Abel 223 (twoGinga HallIncluding), the one under is Abel 222. The presence of the filament was confirmed at the yellow line. It is like a bridge over two clusters of clusters.


According to Einstein's general relativity theory, heavy things (such as the gravity of heavenly bodies) will twist the surrounding universe and time, so that as a result, everything passing through, including light, will have a bent path. When the light from a distant galaxy to the earth comes into something heavy on the way, the light turns and the image of the galaxy distorts. This phenomenon is where the point where the light bends is similar to the optical lensGravity lens (gravity lens effect)It is called.

Schematic diagram created by NASA. The white arrow is light emitted from the galaxy and is distorted before reaching the earth. Therefore, it looks as if it arrived with a straight line drawn in orange.


This is a picture taken by Hubble Observatory. Since the gravitational lens was created by the galaxy Abel 1689, the shape of the galaxy around it appears distorted arcuately.

H. Ford (JHU), M. Clampin (STScI), G. Hartig (STScI), G. Illingworth (UCO / I), NASA, N. Benitez (JHU), T. Broadhurst (Racah Institute of Physics / The Hebrew University) Lick Observatory), the ACS Science Team and ESA

In the above example, Abel 1689 is a lens source, but the gravitational lens has three factors, "Strong lensing (strong gravity lens)", "Weak lensing (weak gravity lens)" "Microlensing (gravity microlens)" due to the influence of the lens source It is divided into types.

Mr. Dietrich and his colleagues, the National Astronomical Observatory of Hawaii ObservatorySubaru TelescopeWe looked at the data of observations of the galaxy's visible and infrared observations, and we found a slight strain and enlargement produced by the "weak gravitational lens" by the filament between Abel 222 and Abel 223. Many astronomers have thought that the gravitational lens of the filament is too weak, so we have thought that it is difficult to detect until the capability of the telescope evolves significantly, but Dietrich et al. Compare this measurement result with X- We concluded that the filament contains almost no hot gas, lacks the galaxy and is invisible at optical wavelengths. In the investigation, Dietrich's team statistically analyzed the data on the light from over 40,000 galaxies, and as a result, that the dark matter filament between Abel 222 and 223 is distorting the spacetime I fixed it.

The result of this measurement is a standard theory on the formation of the universe that the dark matter spreading in the form of a spider web has become a foothold, ordinary substances gathered and galaxies have formedLarge scale structure of the universeIt is a powerful support for this. When the filaments of the spread dark matter intersect each other, a spherical dark matterhall (dark matter halo) is born there and grows greatly. This dark matter halo helped to gather ordinary substances. Especially the large halo becomes a cluster of galaxies, which is the largest object in this universe as one that joins with its own gravity.

It is expected that other dark matter filaments can be found among other cluster of galaxies, but it seems that there are not many candidates that apply to the condition that it can actually be observed from the earth like this time.