barred spiral galaxy
kahkašân-e mârpic-e miledâr
Fr.: galaxie spirale barrée
A → spiral galaxy that exhibits a bar-shaped structure in its nucleus. → galactic bar.
dwarf spiral galaxy
kahkašân-e mârpic-e kutulé (#)
Fr.: galaxie spirale naine
A galaxy that belongs to the spiral class but is significantly smaller.
flocculent spiral galaxy
kahkešân-e mârpic-e pašmin
Fr.: galaxie spirale floculente
A galaxy that has short segments of patchy spiral structure so that the disk appears like the fleece of a sheep. Examples: NGC 2841 and NGC 5055.
From L. floccus "flock of wool" + -ulent; → spiral galaxy.
Kahkešân, → galaxy; mârpic, → spiral; pašmin "woolly, woollen," from pašm "wool" (Mid.Pers. pašm "wool;" Av. pašna- "eyelash, eyelid;" cp. Skt. páksman- "eyelashes;" Gk. pekos "wool, fleece," pek(t)ein "to comb, pluck;" Lith. pešti "to pluck;" O.N. fax "mane").
grand design spiral galaxy
kahkešân-e mârpic-e farsâz
Fr.: galaxie spirale parfaite
A galaxy with prominent → arms that are clearly attached to the central → bulge or → bar spiraling continuously outward until they reach the edge of the visible disk. Some examples are: → Whirlpool galaxy (M51), M74 (NGC 628), and NGC 2997.
M.E. graunt, from O.Fr. grant, grand, from L. grandis "big, great," also "full-grown;" design, from M.E. designen, from L. designare "mark out, designate, appoint," from → de- "out" + signare "to mark," from signum→ sign; → spiral; → galaxy.
Magellanic spiral galaxy
kakhešân-e mârpic-e Mâželâni
Fr.: galaxie spirale magellanique
A class of low-mass galaxies with relatively rare features. In particular, these galaxies are characterized by a → stellar bar whose center is displaced from that of the disk and a one-armed spiral. The → Large Magellanic Cloud (LMC) is considered the prototype of this class of objects. However, despite a wealth of data, there is still a good deal of uncertainty concerning the nature of the LMC's bar. The majority of the observed Magellanic spirals in the nearby Universe share the LMC's structure, in particular the evidence of an offset bar and a one-armed spiral structure. A good example of these systems is NGC 3906, which shows evidence of the bar offset from the photometric center of the galaxy by 1.2 kpc (Pardy et al., 2016, ApJ 827, 149).
→ Magellanic; → spiral; → galaxy.
Fr.: galaxie spirale
A galaxy with a prominent nuclear → bulge and luminous → spiral arms of gas, dust, and young stars that wind out from the nucleus. Masses span the range from 1010 to 1012→ solar masses.
strong arm spiral galaxy
kahkešân-e mârpic bâ bâzu-ye setorg
Fr.: galaxie spirale à forts bras
A galaxy with prominent stellar → spiral arms and little star formation between stellar arms, such as M51.
weak arm spiral galaxy
kahkešân-e mârpic bâ bâzu-ye nezâr
Fr.: galaxie spirale à faibles bras
A gas-rich galaxy that has weak stellar → spiral arms with → interarm gas and star formation more important than a typical → spiral galaxy, such as NGC 4414.