Dorado Group

A rough distance estimate from NGC 1549 (using the Hubble constant as 70) put the cluster at 18.4 megaparsecs (Mpc). Based upon the 2001 work of Tonry et al. the surface brightness fluctuation (SBF) of six member galaxies was averaged and adjusted to estimate the group's distance at in 2007. NGC 1549 and NGC 1553. The dominant group members, ordered by luminosity, are: spiral NGC 1566, lenticular NGC 1553, and elliptical NGC 1549. The group spans an area of the sky 10° square, corresponding to an actual area of around 3 Mpc square. Due to its location in the Fornax Wall, the group is at a similar distance as the Fornax Cluster. The Dorado Group is richer than the Local Group, while still being dominated by disk types of galaxies (i.e. its two brightest members are spiral NGC 1566 and lenticular NGC 1553) and its member galaxies have H I masses on par with non-interacting galaxies of the same morphological type. With the group's apparent crossing time being 12.6 ± 0.6 % of the universe's age, recent analyses deduce that the group is unvirialized, and thus this may explain the abundance of spirals and H I. ==Members==

The table below lists eighteen galaxies that were identified in 1982 as associated with the Dorado Group by John Peter Huchra and Margaret J. Geller with the ones later dropped struck out. In 1989, the list of members was expanded to 46 by Maia, da Costa, & Latham. The Maia et al. 1989 thirty-four added members were: IC 2049, NGC 1536, IC 2058, IC 2032, NGC 1602, NGC 1581, IC 2085, NGC 1522, PGC 15149, NGC 1556, NGC 1527, NGC 1494, NGC 1493, PGC 14416, IC 2000, NGC 1483, NGC 1433, PGC 14078, NGC 1495, NGC 1510, NGC 1512, IC 1959, IC 1986, NGC 1448, NGC 1487, IC 1933, NGC 1311, IC 1954, IC 1914, NGC 1411, IC 1970, PGC 13818, NGC 1249, and PGC 11139. And the six dropped from the 1982 list were: NGC 2082, NGC 1947, NGC 1796, NGC 1688, NGC 1672, and NGC 1559. In 2007, a study of ultracompact dwarfs (UCD) identified one definite and two possible UCD members of the group. The thirty-four added by Ferguson et al. 1990 included IC 2038 and IC 2039. The NGC 1566 Group of Dorado contains H I with MHI = 3.5 M☉ of which 40% alone comes from the NGC 1566 galaxy. More than half of its members are outside its virial radius of 580 kpc which suggests this group is a young non-virialized group. The 2005 Kilborn et al. set of confirmed NGC 1566 Group members (within the Dorado Group) is: ==External links==