NGC 1365 | |
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Observation data (J2000 epoch) | |
Constellation | Fornax |
Right ascension | 03h 33m 36.4s [1] |
Declination | −36° 08′ 25″ [1] |
Redshift | 0.005457±0.000003 [1] |
Heliocentric radial velocity | 1,636±1 km/s [1] |
Distance | 74 Mly (22.69 Mpc)h−1 0.6774 ( Light-travel ) |
Group or cluster | Fornax Cluster |
Apparent magnitude (V) | 10.3 [1] |
Characteristics | |
Type | (R')SBb(s)b [1] |
Size | 201,700 to 306,800 ly (61.85 to 94.08 kpc) ( diameter; 2MASS K-band total and D25.5 B-band isophotes) [1] |
Apparent size (V) | 11.2′ × 6.2′ [1] |
Other designations | |
Great Barred Spiral Galaxy, ESO 358-G 017, NGC 1365, UGC 5887, LEDA 13179, MCG -06-08-026, PGC 13179 [1] , VV 825 |
NGC 1365, also known as the Fornax Propeller Galaxy [2] or the Great Barred Spiral Galaxy, [3] is a double-barred spiral galaxy about 75 million light-years away in the constellation Fornax.
NGC 1365 is a large barred spiral galaxy in the Fornax cluster. Within the larger long bar stretching across the center of the galaxy appears to be a smaller bar that comprises the core, with an apparent size of about 50″ × 40″. [4] This second bar is more prominent in infrared images of the central region of the galaxy, and likely arises from a combination of dynamical instabilities of stellar orbits in the region, along with gravity, density waves, and the overall rotation of the disc. The inner bar structure likely rotates as a whole more rapidly than the larger long bar, creating the diagonal shape seen in images.
The spiral arms extend in a wide curve north and south from the ends of the east–west bar and form an almost ring like Z-shaped halo. [4] Astronomers think NGC 1365's prominent bar plays a crucial role in the galaxy's evolution, drawing gas and dust into a star-forming maelstrom and ultimately feeding material into the central black hole. [5]
NGC 1365, including its two outer spiral arms, spreads over around 300,000 light-years. Different parts of the galaxy take different times to make a full rotation around the core of the galaxy, with the outer parts of the bar completing one circuit in about 350 million years. NGC 1365 and other galaxies of its type have come to more prominence in recent years with new observations indicating that the Milky Way could also be a barred spiral galaxy. Such galaxies are quite common — two thirds of spiral galaxies are barred according to recent estimates, and studying others can help astronomers understand our own galactic home. [6]
Four supernovae have been observed in NGC 1365: SN 1957C (type unknown, mag. 16.5), [7] SN 1983V (type Ic, mag. 13.5) on November 25 1983, [8] SN 2001du (type II, mag. 16.1) on August 24 2001, [9] and SN 2012fr (type Ia, mag. 14.7) on October 27 2012. [10]
The central supermassive black hole in the active nucleus, which has a mass of about 2 million solar masses or half the mass of the Milky Way's central black hole Sagittarius A*, rotates at close to the speed of light. These observations, announced in February 2013, were made using the X-ray telescope satellite NuSTAR. [11] [12]
Fornax is a constellation in the southern celestial hemisphere, partly ringed by the celestial river Eridanus. Its name is Latin for furnace. It was named by French astronomer Nicolas Louis de Lacaille in 1756. Fornax is one of the 88 modern constellations.
Messier 61 is an intermediate barred spiral galaxy in the Virgo Cluster of galaxies. It was first discovered by Barnaba Oriani on May 5, 1779, six days before Charles Messier discovered the same galaxy. Messier had observed it on the same night as Oriani but had mistaken it for a comet. Its distance has been estimated to be 45.61 million light years from the Milky Way Galaxy. 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.
NGC 3115 is a field lenticular (S0) galaxy in the constellation Sextans. The galaxy was discovered by William Herschel on February 22, 1787. At about 32 million light-years away from Earth, it is several times bigger than the Milky Way. It is a lenticular (S0) galaxy because it contains a disk and a central bulge of stars, but without a detectable spiral pattern. NGC 3115 is seen almost exactly edge-on, but was nevertheless mis-classified as elliptical. There is some speculation that NGC 3115, in its youth, was a quasar.
NGC 3982(also known as UGC 6918) is an intermediate spiral galaxy approximately 68 million light-years away in the constellation Ursa Major. It was discovered by William Herschel on April 14, 1789, and misclassified as a planetary nebula. NGC 3982 is a part of the M109 Group.
NGC 6946, sometimes referred to as the Fireworks Galaxy, is a face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years or 7.72 megaparsecs, similar to the distance of M101 in the constellation Ursa Major. Both were once considered to be part of the Local Group, but are now known to be among the dozen bright spiral galaxies near the Milky Way but beyond the confines of the Local Group. NGC 6946 lies within the Virgo Supercluster.
NGC 1300 is a barred spiral galaxy located about 61 million light-years away in the constellation Eridanus. The galaxy is about 110,000 light-years across. It is a member of the Eridanus Cluster, a cluster of 200 galaxies. It was discovered by John Herschel in 1835.
NGC 1097 is a barred spiral galaxy about 45 million light years away in the constellation Fornax. It was discovered by William Herschel on 9 October 1790. It is a severely interacting galaxy with obvious tidal debris and distortions caused by interaction with the companion galaxy NGC 1097A.
NGC 1316 is a lenticular galaxy about 60 million light-years away in the constellation Fornax. It is a radio galaxy and at 1400 MHz is the fourth-brightest radio source in the sky.
NGC 4945 (also known as Caldwell 83) is a barred spiral galaxy in the constellation Centaurus, visible near the star Xi Centauri. The galaxy was discovered by James Dunlop in 1826 and is thought to be similar to the Milky Way Galaxy, although X-ray observations show that NGC 4945 has an unusual energetic Seyfert 2 nucleus that might house a supermassive black hole. Around the nucleus of the galaxy, there is a dense disk of dust and gas, along with many dense star clusters. This object has an estimated mass of 1.4+1.4
−0.7×1011 M☉.
NGC 4639 is a barred spiral galaxy located in the equatorial constellation of Virgo. It was discovered by German-born astronomer William Herschel on April 12, 1784. John L. E. Dreyer described it as "pretty bright, small, extended, mottled but not resolved, 12th magnitude star 1 arcmin to southeast". This is a relatively nearby galaxy, lying approximately 72 million light-years away from the Milky Way. It is a companion to NGC 4654, and the two appear to have interacted roughly 500 million years ago. NGC 4639 is a member of the Virgo Cluster.
NGC 1672 is a barred spiral galaxy located in the constellation Dorado. It was discovered by the astronomer James Dunlop on November 5, 1826. It was originally unclear whether it was a member of the Dorado Group, with some sources finding it to be a member and other sources rejecting its membership. However, recent tip of the red-giant branch (TRGB) measurements indicate that NGC 1672 is located at the same distance as other members, suggesting it is indeed a member of the Dorado Group.
NGC 613 is a barred spiral galaxy located 67 million light years away in the southern constellation of Sculptor. This galaxy was discovered in 1798 by German-English astronomer William Herschel, then re-discovered and catalogued by Scottish astronomer James Dunlop. It was first photographed in 1912, which revealed the spiral form of the nebula. During the twentieth century, radio telescope observations showed that a linear feature in the nucleus was a relatively strong source of radio emission.
NGC 1433 is a barred spiral galaxy with a double ring structure located in the constellation of Horologium. It is at a distance of 46 million light-years from Earth. It is a Seyfert galaxy with an active galactic nucleus. The central region of the galaxy displays intense star formation activity, with an irregular star-forming ring of 5″ radius and weak radio wave emission. Star formation is also noticeable in the spiral arms but not the bar of the galaxy. NGC 1433 is being studied as part of a survey of 50 nearby galaxies known as the Legacy ExtraGalactic UV Survey (LEGUS). A jet of material flowing away from the central black hole of the galaxy extending for only 150 light-years has been found. It is the smallest molecular outflow ever observed in a galaxy beyond our own.
NGC 1448 or NGC 1457 is an unbarred spiral galaxy seen nearly edge-on in the constellation Horologium. It is at a distance of 55 million light years from Earth. It was discovered by John Herschel in 1835.
NGC 1964 is a barred spiral galaxy in the constellation Lepus. The galaxy lies 65 million light years away from Earth, which means, given its apparent dimensions, that NGC 1964 is approximately 100,000 light years across. At its center lies a supermassive black hole, with estimated mass 2.5 × 107M☉. The galaxy features two tightly wound inner spiral arms within a disk with high surface brightness and two outer, more open spiral arms that originate near the inner ring. The outer arms feature few small HII regions.
NGC 3147 is a spiral 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 3147 is about 140,000 light years across. It was discovered by William Herschel on April 3, 1785. It is a Type II Seyfert galaxy.
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 2525 is a barred spiral galaxy located in the constellation Puppis. It is located at a distance of about 70 million light years from Earth, which, given its apparent dimensions, means that NGC 2525 is about 60,000 light years across. It was discovered by William Herschel on February 23, 1791.
NGC 1332 is an almost edge-on elliptical galaxy located in constellation of Eridanus. Situated about 70 million light years away, it is a member of the Eridanus cluster of galaxies, a cluster of about 200 galaxies. It is also the brightest member of the NGC 1332 Group. It was discovered by William Herschel on 9 December 1784.
NGC 3393 is a barred spiral galaxy located in the constellation Hydra. It is located at a distance of circa 180 million light-years from Earth, which, given its apparent dimensions, means that NGC 3393 is about 140,000 light-years across. It was discovered by John Herschel on March 24, 1835. It is a Type II Seyfert galaxy, known to host two supermassive black holes, which are the nearest known pair of supermassive black holes to Earth.