An Etymological Dictionary of Astronomy and Astrophysics

A → dwarf galaxy with a → kiloparsec size → starburst at one end, giving the system a → tadpole or → cometary shape. Also called LEDA-36252, KUG 1138+327. Its distance is 24.5 → megaparsecs (Mpc). The rotation speed of ~ 35 km s^-1 combined with a radius of 1.2 kpc in the bright part of the disk implies that the corresponding → dynamical mass is 3 × 10⁸/ sin²i Msun. This estimate
is a factor of ~ 6 larger than the → stellar mass of 5 × 10⁷ Msun from the → Sloan Digital Sky Survey photometry, but is comparable to the total → neutral hydrogen (H I) mass of ~ 3 × 10⁸ Msun. The metallicity in the → starburst “head” appears to be less than in the rest of the galaxy (the “tail”). This peculiar pattern of metallicity, seen also in several other comparable galaxies, suggests that the starbursts in these systems were triggered by accreting a gas with lower metallicity than in the rest of the galaxy.

The → Hubble Space Telescope observations of Kiso 5639 in six UV-optical and Hα filters were used to resolve the head and derive the star formation properties. The head contains 14 young → star clusters more massive than 10⁴Msun and an overall clustering fraction for star formation of 25-40%. The Hα luminosity of the core region of the head is 8.8 ± 0.16 × 10³⁹ erg s^-1 inside an area of 3.6 × 3.6 square arcsec. The corresponding → star formation rate is ~ 0.04 Msun yr^-1

(Elmegreen et al., 2018, arxiv/1805.08253, and references).

See also: Kiso Survey of UV Bright Galaxies (Miyauchi-Isobe et al., 2010, Pub.Nat.Astro.Ob.Japan, 13, 9).