LEDA 2108986,Paturel, G., et al. (2003), HYPERLEDA. I. Identification and designation of galaxies also known by its Case Western Reserve University designation "Case Galaxy 611" (CG 611),Sanduleak, N.; Pesch, Peter (1987), The case low-dispersion northern sky survey. IV - Galaxies in the Bootes void region is an extremely isolated, early-type dwarf galaxyHernández-Toledo, H.M., et al. (2010), The UNAM-KIAS Catalog of Isolated GalaxiesFuse, C.; Marcum, P.; Fanelli, M. (2012), Extremely Isolated Early-type Galaxies in the Sloan Digital Sky Survey. I. The SampleArgudo-Fernández, M., et al. (2015), Catalogues of isolated galaxies, isolated pairs, and isolated triplets in the local Universe 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 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 galaxiesLiller, M.H. (1966), The Distribution of Intensity in Elliptical Galaxies of the Virgo Cluster. II with their intermediate-scale disks, referred to as "Ellicular" galaxies in recent works.
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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. 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.
See also LEDA 74886 NGC 1271Graham, Alister W.; Ciambur, Bogdan C.; Savorgnan, Giulia A.D. (2016), Disky Elliptical Galaxies and the Allegedly Over-massive Black Hole in the Compact “ES“ Galaxy NGC 1271 Mrk 1216, NGC 1277, NGC 1332, NGC 4291Savorgnan, Giulia A.D. and Graham, Alister W. (2016), Explaining the reportedly overmassive black holes in early-type galaxies with intermediate-scale discs
References