NGC 7552 | |
---|---|
Observation data (J2000 epoch) | |
Constellation | Grus |
Right ascension | 23h 16m 10.7s [1] |
Declination | −42° 35′ 05″ [1] |
Heliocentric radial velocity | 1608 ± 5 km/s [1] |
Distance | 56 Mly (17.2 Mpc) [1] |
Apparent magnitude (V) | 11.2 |
Characteristics | |
Type | (R')SB(s)ab [1] |
Apparent size (V) | 3.4′ × 2.7′ [1] |
Other designations | |
ESO 291- G012, IC 5294, PGC 70884, VV 440 [1] |
NGC 7552 (also known as IC 5294) is a barred spiral galaxy in the constellation Grus. It is at a distance of roughly 60 million light years from Earth, which, given its apparent dimensions, means that NGC 7552 is about 75,000 light years across. It forms with three other spiral galaxies the Grus Quartet. [2]
NGC 7552 was originally discovered and reported in 1826 by James Dunlop and John Herschel added it in the General Catalogue of Nebulae and Clusters as number 3977. However, Lewis Swift reported the galaxy independently in on October 22, 1897, at right ascention 9 arcseconds off the location of the galaxy and was included in Index Catalogue as IC 5294. [3]
NGC 7552 is a barred spiral galaxy, with two spiral arms forming an outer pseudo-ring. The galaxy is seen nearly face on, at an inclination of ~ 28°. [4] The one arm is more prominent and the less prominent arm shows no clear continuation with the bar. The bar is dusty, [5] and four huge HII regions are detected in it. [6] The disk features numerous scattered HII regions in an asymmetric pattern. [7] The total infrared luminosity of the galaxy is 1011.03 L☉ , and thus is categorised as a luminous infrared galaxy. [8]
In 1994, Forbes et al. observed a partial starburst ring with 1 kpc radius at Br-gamma with various hot spots. They also detected a small-scale molecular bar and a large reservoir of molecular material, however, no evidence of current activity was detected at the nucleus. [9] The ring is more than 100 parsecs wide. [4]
The ring is brighter north of the nucleus and there is inhabited by the younger star populations. [7] Brandl et al. detected in near- and mid-infrared nine prominent structures within the ring they identified as star clusters with stellar ages ranging between 5.5 Myr and 6.3 Myr. These clusters account for the 75% of the bolometric luminosity of the starburst ring, with total luminosity of the clusters 2.1 × 1010 L⊙. [4] Numerous supernova remnants have been observed in the ring. Further observations of the galaxy in radio waves showed that NGC 7552 contains three star forming rings of radii 1.0 kpc, 1.9 kpc, and 3.4 kpc as observed by the Very Large Array at 46.9 MHz and the Australia Telescope Compact Array. [10]
One supernova has been observed in NGC 7552: SN 2017bzc (Type Ia, mag. 12.8). [11]
NGC 7552 belongs in NGC 7582 group, also known as the Grus group. Other members of the group include the spiral galaxies NGC 7599, NGC 7590, and NGC 7582, [12] which along with NGC 7552 form the Grus Quartet. A large tidal extension of HI reaches from NGC 7582 to NGC 7552, which is indicative of interactions between the group members, [12] yet NGC 7552 does not have highly disturbed morphology. [13]
The Sombrero Galaxy is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has an isophotal diameter of approximately 29.09 to 32.32 kiloparsecs, making it slightly bigger in size than the Milky Way.
Messier 108 is a barred spiral galaxy about 28 million light-years away from Earth in the northern constellation Ursa Major. It was discovered by Pierre Méchain in 1781 or 1782. From the Earth, this galaxy is seen almost edge-on.
NGC 4725 is an intermediate barred spiral galaxy with a prominent ring structure, located in the northern constellation of Coma Berenices near the north galactic pole. It was discovered by German-born British astronomer William Herschel on April 6, 1785. The galaxy lies at a distance of approximately 40 megalight-years from the Milky Way. NGC 4725 is the brightest member of the Coma I Group of the Coma-Sculptor Cloud, although it is relatively isolated from the other members of this group. This galaxy is strongly disturbed and is interacting with neighboring spiral galaxy NGC 4747, with its spiral arms showing indications of warping. The pair have an angular separation of 24′, which corresponds to a projected linear separation of 370 kly. A tidal plume extends from NGC 4747 toward NGC 4725.
NGC 514 is a low-luminosity, intermediate spiral galaxy in the equatorial constellation of Pisces, located at a distance of approximately 83 million light-years from the Milky Way. It was discovered on 16 October 1784 by astronomer William Herschel. The general form of the galaxy is specified by its morphological classification of SAB(rs)c, which indicates it has a weak bar system at the core (SAB), an incomplete ring formation around the bar (rs), and somewhat loosely-wound spiral arms (c). This galaxy has an H II nucleus with an extended region that displays weak emission lines in the optical range, but not in the near infrared. The suspected supermassive black hole at the core has an estimated mass of 3.2×106 M☉.
NGC 4536 is an intermediate spiral galaxy in the constellation Virgo located about 10° south of the midpoint of the Virgo cluster. However, it is not considered a member of the cluster. Rather, it is a member of the M61 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. The morphological classification in the De Vaucouleurs system is SAB(rs)bc, which indicates it is a weakly barred spiral galaxy with a hint of an inner ring structure plus moderate to loosely wound arms. It does not have a classical bulge around the nucleus.
NGC 1808 is a barred spiral galaxy located in the southern constellation of Columba, about two degrees to the south and east of Gamma Caeli. It was discovered by Scottish astronomer James Dunlop, who described it as a "faint nebula". The galaxy is a member of the NGC 1808 group, which is part of the larger Dorado Group.
NGC 4666 is a spiral galaxy in the equatorial constellation of Virgo, located at a distance of approximately 55 megalight-years from the Milky Way. It was discovered by the German-born astronomer William Herschel on February 22, 1784. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. John L. E. Dreyer described it as "bright, very large, much extended 45°±, pretty suddenly brighter middle". It is a member of an interacting system with NGC 4668 and a dwarf galaxy, and belongs to a small group that also includes NGC 4632.
NGC 4102 is an intermediate barred spiral galaxy located in the northern constellation of Ursa Major. It is visible in a small telescope and has an apparent visual magnitude of 11.2. The galaxy was discovered April 12, 1789 by William Herschel. J. L. E. Dreyer described it as "bright, pretty small, round, brighter middle and bright nucleus". This galaxy is located at a distance of 60 million light years and is receding with a heliocentric radial velocity of 837 km/s. It is a member of the Ursa Major group of galaxies.
NGC 1614 is the New General Catalogue identifier for a spiral galaxy in the equatorial constellation of Eridanus. It was discovered on December 29, 1885 by American astronomer Lewis Swift, who described it in a shorthand notation as: pretty faint, small, round, a little brighter middle. The nebula was then catalogued by Danish-Irish astronomer J. L. E. Drayer in 1888. When direct photography became available, it was noted that this galaxy displayed some conspicuous peculiarities. American astronomer Halton Arp included it in his 1966 Atlas of Peculiar Galaxies. In 1971, Swiss astronomer Fritz Zwicky described it as a "blue post-eruptive galaxy, compact patchy core, spiral plumes, long blue jet SSW".
NGC 5643 is an intermediate spiral galaxy in the constellation Lupus. Based on the tip of the red-giant branch distance indicator, it is located at a distance of about 40 million light-years. NGC 5643 has an active galactic nucleus and is a type II Seyfert galaxy.
NGC 6753 is a massive unbarred spiral galaxy, seen almost exactly face-on, in the southern constellation of Pavo. It was discovered by the English astronomer John Herschel on July 5, 1836. The galaxy is located at a distance of 142 million light years from the Milky Way, and is receding with a heliocentric radial velocity of 3,140 km/s. It does not display any indications of a recent interaction with another galaxy or cluster.
NGC 2336 is a barred spiral galaxy located in the constellation Camelopardalis. It is located at a distance of circa 100 million light years from Earth, which, given its apparent dimensions, means that NGC 2336 is about 200,000 light years across. It was discovered by Wilhelm Tempel in 1876.
NGC 7469 is an intermediate spiral galaxy in the constellation of Pegasus. NGC 7469 is located about 200 million light-years away from Earth, which means, given its apparent dimensions, that NGC 7469 is approximately 90,000 light-years across. It was discovered by William Herschel on November 12, 1784.
NGC 3367 is a barred spiral galaxy located in the constellation Leo. It is located at a distance of about 120 million light years from Earth, which, given its apparent dimensions, means that NGC 3367 is about 85,000 light years across. It was discovered by William Herschel on March 19, 1784.
NGC 7130 is a spiral galaxy located in the constellation Piscis Austrinus. It is located at a distance of about 220 million light years from Earth, which, given its apparent dimensions, means that NGC 7130 is about 100,000 light years across. It was discovered by John Herschel on September 25, 1834, and discovered independently by Lewis Swift on September 17, 1897. The location of the galaxy given in the New General Catalogue was off by 30 arcminutes in declination from the location of the galaxy.
NGC 7531 is an intermediate spiral galaxy located in the constellation Grus. It is located at a distance of about 70 million light-years from Earth, which, given its apparent dimensions, means that NGC 7531 is about 95,000 light years across. It was discovered by John Herschel on September 2, 1836.
IC 1459 is an elliptical galaxy located in the constellation Grus. It is located at a distance of circa 85 million light-years from Earth, which, given its apparent dimensions, means that IC 1459 is about 130,000 light-years across. It was discovered by Edward Emerson Barnard in 1892.
NGC 7418 is an intermediate spiral galaxy located in the constellation Grus. It is located at a distance of circa 60 million light-years from Earth, which, given its apparent dimensions, means that NGC 7418 is about 60,000 light-years across. It was discovered by John Herschel on August 30, 1834.
NGC 877 is an intermediate spiral galaxy located in the constellation Aries. It is located at a distance of circa 160 million light years from Earth, which, given its apparent dimensions, means that NGC 877 is about 115,000 light years across. It was discovered by William Herschel on October 14, 1784. It interacts with NGC 876.
NGC 4848 is a barred spiral galaxy in the constellation Coma Berenices. It is circa 340 million light-years from Earth, which, given its apparent dimensions, means that NGC 4848 is about 170,000 light years across. It was discovered by Heinrich d'Arrest on April 21, 1865. It is considered part of the Coma Cluster, which is in its northwest part. The galaxy has been stripped of its gas as it passed through the cluster.