LEDA 2108986, also known by its

Case Western Reserve University Case Western Reserve University (CWRU) is a private research university in Cleveland, Ohio. Case Western Reserve was established in 1967, when Western Reserve University, founded in 1826 and named for its location in the Connecticut Western Reser ...

designation "Case Galaxy 611" (CG 611), is an extremely isolated, early-type dwarf galaxy with an embedded spiral structure residing in what is likely an intermediate-scale disk. The galaxy was discovered in 1987 by Sanduleak and Pesch, and is located at a distance of about in the

Boötes Void Boötes ( ) is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from la, Boōtēs, which comes from grc-gre, Βοώτης, Boṓtēs ...

and has no significant neighbours within 2.5 Mpc. The galaxy may be a counterpart to the rectangular-shaped galaxy LEDA 74886, in that they both appear to contain an intermediate-scale disk. In the case of LEDA 74886, that disk is orientated edge-on to our line-of-sight. The "early-type galaxy" class is commonly known to contain elliptical galaxies (E) with no substantial stellar disk (perhaps just a small nuclear disk) and lenticular galaxies (S0) with their large-scale disks that dominate the light at large radii. Bridging these two types of galaxies are the ES galaxies with their intermediate-scale disks, referred to as "Ellicular" galaxies in recent works.

Importance

LEDA 2108986 has accreted a gas disk which counter-rotates relative to its stellar disk. It also displays a young spiral pattern within this stellar disk. The presence of such faint disk structures and rotation within some dwarf early-type galaxies in galaxy clusters has often been heralded as evidence that they were once late-type spiral or dwarf irregular galaxies prior to experiencing a cluster-induced transformation, known as

galaxy harassment A galaxy is a system of stars, stellar remnants, interstellar medium, interstellar gas, cosmic dust, dust, dark matter, bound together by gravity. The word is derived from the Ancient Greek, Greek ' (), literally 'milky', a reference to the ...

. The extreme isolation of LEDA 2108986 is proof that dwarf early-type galaxies can be built by accretion events, as opposed to disk-stripping scenarios within the "galaxy harassment" model.

References

{{reflist 2108986 Dwarf galaxies Boötes

Importance

See also

References