Profile: a lonely Galaxy

ESO 461-36 - a dwarf galaxy in the local isolated blank (image credit: UDS/CNRS)

The vast majority of galaxies exist in clusters. These clusters are free, by filaments and leaves of galaxies, between those gigantic Galactic voids are almost completely on larger scales of galaxies. These cavities are often hundreds of millions of light years across. Rarely, a lonely Galaxy breaks the empty. Our Milky Way Galaxy is located in one of which this large leaves the local empty borders which is almost 200 million light years across. In the empty it preliminary identification of up to sixteen galaxies, but actually at a distance would be, it placed only confirmed in the blank.

This dwarf galaxy is ESO 461-36 and was the objective of the study. As expected of galaxies is empty in the ESO 461-36 with discovered no galaxies within 10 million light years exceptionally isolated.

It is surprising for such a lonely Galaxy that when astronomers compared the stellar disc of the Galaxy with a map of hydrogen gas, the gas disk of about 55 ° was inclined. The team suggests that due to a bar in the Galaxy as a funnel can along the gas to the main disk accrete could. Another possibility is that this Galaxy recently on a small scale Fusion was involved in. The tide of even a small satellite drag could potentially drag the gas into a different orbit.

This CD of gas is also unusually prolonged several times the size of the visual part of the Galaxy. During intergalactic space a great vacuum in comparison to the place within cavities, it is a relatively dense environment. This extreme under density can help reduce that puffing but there the gaseous disc, with the rarity of the void galaxies, precious little to the astronomers can compare.

Compared with other dwarf galaxies is also exceptionally dim. ESO 461-36 To measure the brightness astronomers use generally a measure known as the mass of the Galaxy, in solar masses, divides by the total luminosity, the mass to light ratio with the Sun as a basis. Typical galaxies have mass to light ratios between 2 and 10. common dwarf galaxies may have relationships in the 30′s. But ESO 461-36 has a ratio of 89, so that it known as the darkest galaxies.

Astronomers finally seeking to discover more void galaxies. Not only do such galaxies are interesting test environments for the understanding of galactic evolution in worldly environments, but they serve as tests for cosmological models. In particular forecast ΛCDM model, which it should be dispersed far more galaxies in the cavities, as are complied with. Future observations could help to resolve such discrepancies.

Tagged as: cosmology, dwarf galaxies, galaxies, void

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