Bullet Group

Last updated
Bullet Group
Observation data (Epoch J2000.0 [1] )
Constellation(s) Hydra
Right ascension 08h 54m 46.5480s [1]
Declination −01° 21 37.262 [1]
Redshift 0.351 [1]
Binding mass (2.4±0.6)×1014 [2]   M
Other designations
Bullet Group, [3] SL2S J08544-0121 [4]
See also: Galaxy group, Galaxy cluster, List of galaxy groups and clusters

The Bullet Group (SL2S J08544-0121) is a newly merging group of galaxies, a merger between two galaxy groups to form a new larger one, that recently had a high speed collision between the two component groups. The group exhibits separation between its dark matter and baryonic matter components. The galaxies occur in two clumps, while the gas has expanded into a billowing cloud encompassing all three clumps. As of 2014, it is one of the few galaxy clusters known to show separation between the dark matter and baryonic matter components. The group is named after the Bullet Cluster, a similar merging galaxy cluster, except on a smaller scale, being of groups instead of clusters. [2] [3] The bimodal distribution of galaxies was found at discovery in 2008. The galaxy group is a gravitational lens and strongly lenses a more distant galaxy behind it, at z=~1.2 [3] [4]

Contents

Characteristics

As of 2014, the group is the smallest mass object to exhibit separation between its dark matter and baryonic matter components. [2]

The galaxy group is dominated by one elliptical galaxy, situated in one of the two concentrations, while the other node has two large bright galaxies, which do not dominate the group. [4] The group has an apparent radius of 200 arcseconds, and a virial radius of 1 megaparsec. [5]

See also

Related Research Articles

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In astronomy, dark matter is a hypothetical form of matter that appears not to interact with light or the electromagnetic field. Dark matter is implied by gravitational effects which cannot be explained by general relativity unless more matter is present than can be seen. Such effects occur in the context of formation and evolution of galaxies, gravitational lensing, the observable universe's current structure, mass position in galactic collisions, the motion of galaxies within galaxy clusters, and cosmic microwave background anisotropies.

<span class="mw-page-title-main">Galaxy groups and clusters</span> Largest known gravitationally bound object in universe; aggregation of galaxies

Galaxy groups and clusters are the largest known gravitationally bound objects to have arisen thus far in the process of cosmic structure formation. They form the densest part of the large-scale structure of the Universe. In models for the gravitational formation of structure with cold dark matter, the smallest structures collapse first and eventually build the largest structures, clusters of galaxies. Clusters are then formed relatively recently between 10 billion years ago and now. Groups and clusters may contain ten to thousands of individual galaxies. The clusters themselves are often associated with larger, non-gravitationally bound, groups called superclusters.

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<span class="mw-page-title-main">Dwarf galaxy problem</span>

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<span class="mw-page-title-main">Lambda-CDM model</span> Model of Big Bang cosmology

The Lambda-CDM, Lambda cold dark matter, or ΛCDM model is a mathematical model of the Big Bang theory with three major components:

  1. a cosmological constant, denoted by lambda (Λ), associated with dark energy
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<span class="mw-page-title-main">Galaxy group</span> Aggregation of galaxies with 50 or fewer members

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<span class="mw-page-title-main">Musket Ball Cluster</span> Collision of two galaxy clusters in the constellation Cancer

The Musket Ball Cluster is a galaxy cluster that exhibits separation between its baryonic matter and dark matter components. The cluster is a recent merger of two galaxy clusters. It is named after the Bullet Cluster, as it is a slower collision, and older than the Bullet Cluster. This cluster is further along the process of merger than the Bullet Cluster, being some 500 million years older, at 700 million years old. The cluster was discovered in 2011 by the Deep Lens Survey. As of 2012, it is one of the few galaxy clusters to show separation between its dark matter and baryonic matter components.

<span class="mw-page-title-main">Serpens–Aquila Rift</span> Region located in the constellations Serpens and Aquila that contains dark interstellar clouds

The Serpens–Aquila Rift (also known as the Aquila Rift) is a region of the sky in the constellations Aquila, Serpens Cauda, and eastern Ophiuchus containing dark interstellar clouds. The region forms part of the Great Rift, the nearby dark cloud of cosmic dust that obscures the middle of the galactic plane of the Milky Way, looking inwards and towards its other radial sectors. The clouds that form this structure are called "molecular clouds", constituting a phase of the interstellar medium which is cold and dense enough for molecules to form, particularly molecular hydrogen (H2). These clouds are opaque to light in the optical part of the spectrum due to the presence of interstellar dust grains mixed with the gaseous component of the clouds. Therefore, the clouds in the Serpens-Aquila Rift block light from background stars in the disk of the Galaxy, forming the dark rift. The complex is located in a direction towards the inner Galaxy, where molecular clouds are common, so it is possible that not all components of the rift are at the same distance and physically associated with each other.

<span class="mw-page-title-main">Bullet Galaxy</span>

The Bullet Galaxy (RXC J2359.3-6042 CC) is a galaxy in the galaxy cluster RXC J2359.3-6042 (Abell 4067 or ACO 4067). The Bullet Galaxy is the sole component of one half of a cluster merger between the bulk of the cluster and this galaxy, which is plowing through the cluster, similar to how merging clusters Bullet Cluster and Bullet Group have merged. Unlike those two mergers, the Bullet Galaxy's merger is between one galaxy and a galaxy cluster. The cluster merger is happening at a lower speed than the Bullet Cluster, thus allowing the core of the Bullet Galaxy to retain cool gas and remain relatively undisturbed by its passage through the larger cluster. This cluster merger is the first one observed between a single galaxy and a cluster. The galaxy and cluster lies at redshift z=0.0992, some 1.4×109 ly (4.3×108 pc) away. The galaxy is traveling through the cluster at a speed of 1,310 km/s (2,900,000 mph).

<span class="mw-page-title-main">Georges Meylan</span> Swiss astronomer

Georges Meylan is a Swiss astronomer, born on July 31, 1950, in Lausanne, Switzerland. He was the director of the Laboratory of Astrophysics of the Swiss Federal Institute of Technology (EPFL) in Lausanne, Switzerland, and now a professor emeritus of astrophysics and cosmology at EPFL. He is still active in both research and teaching.

<span class="mw-page-title-main">NGC 3311</span> Galaxy in the constellation Hydra

NGC 3311 is a super-giant elliptical galaxy located about 190 million light-years away in the constellation Hydra. The galaxy was discovered by astronomer John Herschel on March 30, 1835. NGC 3311 is the brightest member of the Hydra Cluster and forms a pair with NGC 3309 which along with NGC 3311, dominate the central region of the Hydra Cluster.

<span class="mw-page-title-main">NGC 720</span> Galaxy in the constellation Cetus

NGC 720 is an elliptical galaxy located in the constellation Cetus. It is located at a distance of circa 80 million light years from Earth, which, given its apparent dimensions, means that NGC 720 is about 110,000 light years across. It was discovered by William Herschel on October 3, 1785. The galaxy is included in the Herschel 400 Catalogue. It lies about three and a half degrees south and slightly east from zeta Ceti.

<span class="mw-page-title-main">Abell 697 BCG</span> Brightest cluster galaxy in the constellation Lynx

Abell 697 BCG, also known as PGC 2079433, is a massive type-cD elliptical galaxy residing as the brightest cluster galaxy in Abell 697 galaxy cluster. It is located in the constellation of Lynx and has a redshift of 0.28, meaning the galaxy is located 3.5 billion light-years away from Earth.

References

  1. 1 2 3 4 "[LCG2009] SL2S Group J08544-0121 -- Group of Galaxies". SIMBAD . Retrieved 18 July 2014.
  2. 1 2 3 F. Gastaldello; M. Limousin; G. Foëx; R. P. Muñoz; T. Verdugo; V. Motta; et al. (22 Apr 2014). "Dark matter-baryons separation at the lowest mass scale: the Bullet Group". Monthly Notices of the Royal Astronomical Society: Letters. 442 (1) (published July 2014): L76–L80. arXiv: 1404.5633 . Bibcode:2014MNRAS.442L..76G. doi: 10.1093/mnrasl/slu058 .
  3. 1 2 3 XMM-Newton (6 June 2014). "Cosmic collision in the Bullet Group". European Space Agency.
  4. 1 2 3 M. Limousin; R. Cabanac; R. Gavazzi; J.-P. Kneib; V. Motta; J. Richard; et al. (4 December 2008). "A New Window of Exploration in the Mass Spectrum: Strong Lensing by Galaxy Groups in the SL2S". Astronomy and Astrophysics. 502 (2) (published August 2009): 445–456. arXiv: 0812.1033 . Bibcode:2009A&A...502..445L. doi:10.1051/0004-6361/200811473. S2CID   10168407.
  5. Muñoz, R. P.; Motta, V.; Verdugo, T.; Garrido, F.; Limousin, M.; Padilla, N.; et al. (11 December 2012). "Dynamical analysis of strong-lensing galaxy groups at intermediate redshift". Astronomy & Astrophysics. 552 (published April 2013): 18. arXiv: 1212.2624 . Bibcode:2013A&A...552A..80M. doi:10.1051/0004-6361/201118513. S2CID   17865754. A80.