Group of Galaxies NGC 5981/2/5: Draco Trio

NGC 5981/2/5
NGC 5981/2/5: Galaxy group in Draco; 400 mm MPT; Newtonfokus f=1814 mm; Paracorr; Canon 40D; 12 x 480s bei 800 ASA; Observatory Hubelmatt, Lucerne; © 14. Mai 2012 Roland Stalder

History

The galaxies NGC 5982 and NGC 5985 were discovered on 15 May 1788 by the German-British astronomer William Herschel with his self-made 18.7 inch f/12.8 reflecting telescope in Slough, England. He listed them under the designations II 764 and II 765. On May 6 On 18 May 1850, the intelligent astronomer and physicist George Stoney organized the huge 72 inch reflecting telescope «Leviathan» of his employer William Parsons, 3rd Earl of Rosse, in the intelligent Birr Castle on this region of the sky and discovered two other small galaxies west of it, which later included in the New General Catalog by John LE Dreyer under the designations NGC 5976 and NGC 5981. [196, 277, 313]

Physical Properties

NGC 5981/2/5
NGC 5981/2/5: Image taken with the Mayall 4m telescope on Kitt Peak [457]

NGC 5981 is a barred spiral galaxy of morphological type SBab, seen edge on. NGC 5982 is an elliptical galaxy with a LINER-type active galactic core. There are indications that it has already swallowed one or two smaller galaxies. NGC 5985 is a barred spiral galaxy of morphological type SBbc. It is a Seyfert galaxy with an active core. [145, 457]

These galaxies form the gravitationally bound NGC 5982 group of galaxies, which also includes NGC 5987 (1° 17' south of NGC 5985) and NGC 5989 (29' northeast of NGC 5985). [458] It is at a distance of about 30-61 Mpc (98-199 light-years). According to Simbad [145], the two smaller galaxies NGC 5976 and UGC 9934 (also sometimes referred to as NGC 5976A) do not belong to this group. HyperLEDA [134] counts them among the NGC 5982 galaxy group, which consists of a total of 16 galaxies. On NED [194] one finds a distance of 63.0±4.4 Mpc for NGC 5976 and 44.1±3.2 Mpc for UGC 9931, which also speaks for a group affiliation.

«Catalogue of Principal Galaxies (PGC)», Paturel et al. 1989 [144]
NameRA [hms]Dec [dms]mTypeDim [']Btot [mag]HRV [km/s]PA [°]
PGC 5556115 36 01.5+59 34 09SB1.0 x 1.015.2
PGC 55609, NGC 597615 36 48.1+59 23 52L.8 x .415.7
PGC 55647, NGC 598115 37 53.2+59 23 34S2.7 x .313.95029140
PGC 55674, NGC 598215 38 40.0+59 21 22E3.0 x 2.112.02904110
PGC 55725, NGC 598515 39 37.7+59 19 57SBR5.4 x 2.711.9251913

Finder Chart

The galaxy group NGC 5981/2/5 is located in the constellation Draco (Dragon) between the two stars θ Draconis and ι Draconis (Edasich), about a third closer to the latter and thus easy to find. The best viewing time is February to September, when this circumpolar constellation is at its highest at night.

Chart Group of Galaxies NGC 5981/2/5: Draco Trio
Group of Galaxies NGC 5981/2/5: Draco Trio in constellation Draco. Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

More Objects Nearby (±20°)

References

134Lyon-Meudon Extragalactic Database (LEDA); leda.univ-lyon1.fr
144Catalogue of Principal Galaxies (PGC); Paturel G., Fouque P., Bottinelli L., Gouguenheim L.; Astron. Astrophys. Suppl. Ser. 80, 299 (1989); cdsarc.unistra.fr/viz-bin/cat/VII/119 (2021-02-18)
145SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
194NASA/IPAC Extragalactic Database (NED); ned.ipac.caltech.edu (2020-12-27)
196Celestial Atlas by Curtney Seligman; cseligman.com/text/atlas.htm (2020-12-28)
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
313«A New General Catalogue of Nebulae and Clusters of Stars, being the Catalogue of the late Sir John F.W. Herschel, Bart., revised, corrected, and enlarged» Dreyer, J. L. E. (1888); Memoirs of the Royal Astronomical Society. 49: 1–237; Bibcode:1888MmRAS..49....1D
457Trio of Galaxies (NGC 5981, NGC 5982 and NGC 5985); noirlab.edu/public/images/noao-ngc5982 (2021-12-22)
458«Galaxy groups and clouds in the local (z∼ 0.01) Universe» Dmitry Makarov, Igor Karachentsev; Monthly Notices of the Royal Astronomical Society, Volume 412, Issue 4, April 2011, Pages 2498–2520; DOI:10.1111/j.1365-2966.2010.18071.x