NGC 55 | |
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![]() Irregular Galaxy NGC 55 (La Silla Observatory) | |
Observation data (J2000 epoch) | |
Constellation | Sculptor [1] |
Right ascension | 00h 14m 53.6s [2] |
Declination | −39° 11′ 48″ [2] |
Redshift | 129 ± 2 km/s [2] |
Distance | 6.5 ± 0.65 Mly (2.00 ± 0.2 Mpc) [3] [4] [a] |
Apparent magnitude (V) | 7.87 [5] [6] |
Characteristics | |
Type | SB(s)m [2] |
Mass | (2.0 ± 0.4) × 1010 M☉ |
Apparent size (V) | 32.4′ × 5.6′ [2] |
Other designations | |
PGC 1014, [2] Caldwell 72, 2MASS J00145360-3911478, IRAS F00124-3929, ESO 293-50, MCG -07-01-013 [5] |
NGC 55, also known as the String of Pearls Galaxy, [7] 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. [8] It has an estimated mass of (2.0 ± 0.4) × 1010M☉. [9]
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. [10]
It is likely that NGC 55 and NGC 300 form a gravitationally bound pair. [4]
The Webb Society Deep-Sky Observer's Handbook [11] 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. [12]
The Sculptor Group is a loose group of galaxies visible near the south galactic pole. The group is one of the closest groups of galaxies to the Local Group; the distance to the center of the group from the Milky Way is approximately 3.9 Mpc (12.7 Mly).
NGC 300 (also known as Caldwell 70 or the Sculptor Pinwheel Galaxy) is a spiral galaxy in the constellation Sculptor. It is one of the closest galaxies to the Local Group, and probably lies between the latter and the Sculptor Group. It is the brightest of the five main spirals in the direction of the Sculptor Group. It is inclined at an angle of 42° when viewed from Earth and shares many characteristics of the Triangulum Galaxy. It is 94,000 light-years in diameter, somewhat smaller than the Milky Way, and has an estimated mass of (2.9 ± 0.2) × 1010M☉.
NGC 404 is a field galaxy located about 10 million light years away in the constellation Andromeda. It was discovered by William Herschel in 1784, and is visible through small telescopes. NGC 404 lies just beyond the Local Group and does not appear gravitationally bound to it. It is located within 7 arc-minutes of second magnitude star Mirach, making it a difficult target to observe or photograph and granting it the nickname "Mirach's Ghost".
The Sculptor Galaxy is an intermediate spiral galaxy in the constellation Sculptor. The Sculptor Galaxy is a starburst galaxy, which means that it is currently undergoing a period of intense star formation.
The Sculptor Dwarf Irregular Galaxy (SDIG) is an irregular galaxy in the constellation Sculptor. It is a member of the NGC 7793 subgroup of the Sculptor Group. The galaxy was discovered in 1976.
NGC 2976 is a peculiar dwarf galaxy in the northern circumpolar constellation of Ursa Major. It was discovered by German-born astronomer William Herschel on November 8, 1801, and catalogued as H I.285. J. L. E. Dreyer described it as, "bright, very large, much extended 152°, star involved". It is a member of the M81 Group and lies 1° 20′ to the southwest of Messier 81. The projected separation of this galaxy from the M81 Group is 190 kpc.
NGC 247 is an intermediate spiral galaxy about 11.1 Mly away in the constellation Cetus. This distance was confirmed in late February 2011. Previous measurements showed that the galaxy was about 12.2 Mly away, but this was proved to be wrong. NGC 247 is a member of the Sculptor Group, and is 70 000 light years in diameter.
NGC 4236 is a barred Magellanic spiral galaxy located in the constellation Draco.
NGC 4605 is a dwarf barred spiral galaxy in the constellation Ursa Major, located at a distance of 18.1 ± 0.3 megalight-years from the Milky Way. Physically it is similar in size and in B-band absolute magnitude to the Large Magellanic Cloud. It is a member of the M81 Galaxy Group, along with Messier 81 and Messier 101.
NGC 4710 is an edge-on lenticular galaxy in the northern constellation of Coma Berenices. It was discovered on March 21, 1784 by German-British astronomer William Herschel. This galaxy has a B-band visual magnitude of 11.60 and an angular size of 3.0′ × 0.8′. It is located at a distance of 54.5 ± 3.6 million light-years (16.7 ± 1.1 Mpc) from the Milky Way, and is receding with a heliocentric radial velocity of 1,129 km/s. This is a member of the Virgo Cluster, with a projected offset of ~6° from the cluster center and a cluster crossing time of around two billion years.
NGC 6340 is an unbarred spiral galaxy in the northern constellation of Draco. It was discovered by German-British astronomer William Herschel on June 6, 1788. The galaxy is located approximately 55 million light-years (17 Mpc) away, and is receding with a heliocentric radial velocity of 1,217 km/s. It is the largest member of a triplet of galaxies known as the NGC 6340 group.
NGC 45 is a low surface brightness spiral galaxy in the equatorial constellation of Cetus. It was discovered on 11 November 1835 by the English astronomer John Herschel. The galaxy is located at a distance of 22 million light years and is receding with a heliocentric radial velocity of 466 km/s. It is located in the vicinity of the Sculptor Group, but is most likely a background galaxy.
NGC 3669 is a barred spiral galaxy in the constellation Ursa Major. It was discovered by William Herschel on March 18, 1790. The galaxy is seen edge-on and appears to be slightly warped. It has a small bulge.
NGC 1792 is a spiral galaxy located in the southern Columba constellation. It was discovered by Scottish astronomer James Dunlop on October 4, 1826. This galaxy is located at a distance of about 36.4 million light-years and is receding from the Milky Way with a heliocentric radial velocity of 1,208 km/s. NGC 1792 is a member of the NGC 1808 cluster of galaxies.
NGC 3642 is a spiral galaxy in the constellation Ursa Major. The galaxy has a low-ionization nuclear emission-line region. It is located at a distance of circa 30 million light years from Earth, which, given its apparent dimensions, means that NGC 3642 is about 50,000 light years across. The galaxy is characterised by an outer pseudoring, which was probably formed after the accretion of a gas rich dwarf galaxy.
NGC 4586 is a spiral galaxy located about 50 million light-years away in the constellation Virgo. The galaxy was discovered by astronomer William Herschel on February 2, 1786. Although listed in the Virgo Cluster Catalog, NGC 4586 is considered to be a member of the Virgo II Groups which form a southern extension of the Virgo cluster. NGC 4586 is currently in the process of infalling into the Virgo Cluster and is predicted to enter the cluster in about 500 million years.
NGC 7723 is a barred spiral galaxy located in the constellation Aquarius. It is located at a distance of circa 90 million light years from Earth, which, given its apparent dimensions, means that NGC 7723 is about 95,000 light years across. It was discovered by William Herschel on November 27, 1785. The galaxy is included in the Herschel 400 Catalogue. It lies 1.5 degrees north-northwest from Omega1 Aquarii. It can be seen with a 4-inch telescope under dark skies.
NGC 5965 is a spiral galaxy located in the constellation Draco. It is located at a distance of circa 150 million light years from Earth, which, given its apparent dimensions, means that NGC 5965 is about 260,000 light years across. It was discovered by William Herschel on May 5, 1788.
NGC 5982 is an elliptical galaxy located in the constellation Draco. It is located at a distance of circa 130 million light years from Earth, which, given its apparent dimensions, means that NGC 5982 is about 100,000 light years across. It was discovered by William Herschel on May 25, 1788.
NGC 4302 is an edge-on spiral galaxy located about 55 million light-years away in the constellation Coma Berenices. It was discovered by astronomer William Herschel on April 8, 1784 and is a member of the Virgo Cluster.