LEDA 2108986,[3] also known by its Case Western Reserve University designation "Case Galaxy 611" (CG 611),[4] is an extremely isolated, early-type dwarf galaxy[5][6][7] with an embedded spiral structure residing in what is likely an intermediate-scale disk.[8] The galaxy was discovered in 1987 by Sanduleak and Pesch, and is located at a distance of about 45.7 megaparsecs (149,000,000 ly) in the Boötes Void and has no significant neighbours within 2.5 Mpc.

LEDA 2108986
False color image of galaxy LEDA 2108986, taken by the Canada–France–Hawaii Telescope. The contrast of this image has been adjusted to highlight the internal bar/spiral structure.
Observation data (J2000 epoch)
ConstellationBoötes
Right ascension15h 03m 15.557s[1]
Declination+37° 45′ 57.96″[1]
Distance45.7 Mpc (149,000,000 ly) h−1
0.678
Characteristics
TypeES, E/S0[2]
Other designations
2MASX J15031550+3745580, SDSS J150315.54+374558.0[1]

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[9] with their intermediate-scale disks, referred to as "Ellicular" galaxies in recent works.[8]

Importance

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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

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References

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  1. ^ a b c "2MASX J15031550+3745580". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 March 2018.
  2. ^ NED, [1] (accessed 20 March 2018)
  3. ^ Paturel, G., et al. (2003), HYPERLEDA. I. Identification and designation of galaxies
  4. ^ Sanduleak, N.; Pesch, Peter (1987), The case low-dispersion northern sky survey. IV - Galaxies in the Bootes void region
  5. ^ Hernández-Toledo, H.M., et al. (2010), The UNAM-KIAS Catalog of Isolated Galaxies
  6. ^ Fuse, C.; Marcum, P.; Fanelli, M. (2012), Extremely Isolated Early-type Galaxies in the Sloan Digital Sky Survey. I. The Sample
  7. ^ Argudo-Fernández, M., et al. (2015), Catalogues of isolated galaxies, isolated pairs, and isolated triplets in the local Universe
  8. ^ a b Graham, Alister W.; Janz, Joachim; Penny, Samantha J.; Chilingarian, Igor V.; Ciambur, Bogdan C.; Forbes, Duncan A.; Davies, Roger L. (May 8, 2017). "Implications for the origin of dwarf early-type galaxies: a detailed look at the isolated rotating dwarf early-type galaxy CG 611, with ramifications for the Fundamental Plane's SK2 kinematic scaling and the spin-ellipticity diagram". The Astrophysical Journal. 840 (2): 68. arXiv:1705.03587. Bibcode:2017ApJ...840...68G. doi:10.3847/1538-4357/aa6e56. S2CID 54018338.
  9. ^ Liller, M.H. (1966), The Distribution of Intensity in Elliptical Galaxies of the Virgo Cluster. II
  10. ^ Graham, 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
  11. ^ Savorgnan, Giulia A.D. and Graham, Alister W. (2016), Explaining the reportedly overmassive black holes in early-type galaxies with intermediate-scale discs