NGC 55 explained

NGC 55
Epoch:	J2000
Constellation Name:	Sculptor^[1]
Type:	SB(s)m^[2]
Z:	129 ± 2 km/s
Dist Ly:	6.5 ± 0.65 Mly (2.00 ± 0.2 Mpc)
Appmag V:	7.87^[3] ^[4]
Size V:	32.4 × 5.6
Mass:	(2.0 ± 0.4) × 10^10
Names:	PGC 1014, Caldwell 72, 2MASS J00145360-3911478, IRAS F00124-3929, ESO 293-50, MCG -07-01-013

NGC 55, also known as the String of Pearls Galaxy,^[5] is a Magellanic type barred spiral galaxy located about 6.5 million light-years away in the constellation Sculptor. Along with its neighbor NGC 300, it is one of the closest galaxies to the Local Group, probably lying between the Milky Way and the Sculptor Group.^[6] It has an estimated mass of (2.0 ± 0.4) × 10¹⁰ .^[7]

Nearby galaxies and group information

NGC 55 and the spiral galaxy NGC 300 have traditionally been identified as members of the Sculptor Group, a nearby group of galaxies in the constellation of the same name. However, recent distance measurements indicate that the two galaxies actually lie in the foreground.^[8]

It is likely that NGC 55 and NGC 300 form a gravitationally bound pair.^[9]

Visual appearance

The Webb Society Deep-Sky Observer's Handbook^[10] writes the following about NGC 55: "Nearly edge-on and appears asymmetrical with some signs of dust near the bulge, which is diffuse, broad and somewhat elongated with the south edge sharp; southeast of the bulge it is strongly curved and lined with 4 or 5 faint knots; north edge of the curve is sharp." Burnham calls it "one of the outstanding galaxies of the southern heavens", somewhat resembling a smaller version of the Large Magellanic Cloud.^[11]

See also

• • NGC 4236 NGC 4631

Notes

1. average(6.9 ± 0.7,^[12] 7.5 ± 1.1) = ((6.9 + 7.5) / 2) ± ((0.7² + 1.1²)^0.5 / 2) = 7.2 ± 0.7

External links

• NGC 55 in Sculptor
• SEDS: Spiral Galaxy NGC 55

Notes and References

1. Book: R. W. Sinnott . The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer . 1988 . Sky Publishing Corporation and Cambridge University Press . 978-0-933346-51-2.
2. Web site: NASA/IPAC Extragalactic Database . Results for NGC 55 . 2006-10-17.
3. NGC 55 . 2009-11-29.
4. Armando . Gil de Paz . etal . 2007 . The GALEX Ultraviolet Atlas of Nearby Galaxies . . 173 . 2 . 185–255 . astro-ph/0606440 . 10.1086/516636. 2007ApJS..173..185G . 119085482 .
5. Book: Stoyan, Ronald. Schurig. Stephan. interstellarum Deep Sky Atlas. Cambridge University Press; Oculum-Verlag GmbH. Erlangen. 2014. 978-1-107-50338-0. 920437579.
6. Web site: New General Catalog Objects: NGC 50 - 99. cseligman.com. en-US. 2017-12-12.
7. Gas and dark matter in the Sculptor group: NGC 55. 2013. 10.1093/mnras/stt1271. Westmeier. T.. Koribalski. B. S.. Braun. R.. Monthly Notices of the Royal Astronomical Society. 434. 4. 3511–3525. free. 1307.2962.
8. I. D. Karachentsev . etal . Distances to nearby galaxies in Sculptor . . 2003 . 404 . 1 . 93–111 . 2003A&A...404...93K . 10.1051/0004-6361:20030170. astro-ph/0302045 . 54977869 .
9. van de Steene . G. C. . etal . Distance determination to NGC 55 from the planetary nebula luminosity function . . 2006 . 455 . 3 . 891–896 . 2006A&A...455..891V . 10.1051/0004-6361:20053475. free .
10. Book: Jones, K. G. . Webb Society Deep-Sky Observer's Handbook . Enslow Publishers . 1981 . 8249797M . 978-0-89490-134-8 . registration .
11. Book: Robert Burnham Jr. . Burnham's Celestial Handbook . III . 1978 . Dover . New York . 978-0-486-24065-7 . 1733 .
12. Karachentsev, I. D. . Kashibadze, O. G. . Masses of the local group and of the M81 group estimated from distortions in the local velocity field . . 2006 . 49 . 1 . 3–18 . 2006Ap.....49....3K . 10.1007/s10511-006-0002-6. 120973010 .