NGC 1365

NGC 1365, also known as the Great Barred Spiral Galaxy,[2] is a double-barred spiral galaxy about 75 million light-years away in the constellation Fornax.

NGC 1365
Observation data (J2000 epoch)
ConstellationFornax
Right ascension03h 33m 36.4s[1]
Declination−36° 08′ 25″[1]
Redshift0.005457±0.000003[1]
Heliocentric radial velocity1,636±1 km/s[1]
Distance74 Mly (22.69 Mpc)h−1
0.6774
(Light-travel)
Group or clusterFornax Cluster
Apparent magnitude (V)10.3[1]
Characteristics
Type(R')SBb(s)b[1]
Size201,700 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

Characteristics

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″.[3] 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.[3] 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.[4]

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.[5]

Supernovae

Four supernovae have been observed in NGC 1365: SN 1957C (type unknown, mag. 16.5),[6] SN 1983V (type Ic, mag. 13.5) on November 25 1983,[7] SN 2001du (type II, mag. 16.1) on August 24 2001,[8] and SN 2012fr (type Ia, mag. 14.7) on October 27 2012.[9]

Supermassive black hole

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.[10][11]

See also

References
  1. "NASA/IPAC Extragalactic Database". Results for NGC 1365. Retrieved 2006-11-21.
  2. Garlick, Mark A. (2004). Astronomy: A Visual Guide. Firefly Books. p. 293. ISBN 978-1-55297-958-7.
  3. Kepple, George Robert; Glen W. Sanner (1998). The Night Sky Observer's Guide. Vol. 1. Willmann-Bell, Inc. p. 198. ISBN 978-0-943396-58-3.
  4. "APOD: 2018 December 28 - NGC 1365: Majestic Island Universe". NASA. 28 December 2018. Retrieved 28 July 2019. Public Domain This article incorporates text from this source, which is in the public domain.
  5. "An Elegant Galaxy in an Unusual Light". European Southern Observatory. 22 September 2010. Retrieved 28 July 2019. Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.
  6. admin. "NGC 1365: The Great Barred Spiral Galaxy | Constellation Guide". Retrieved 2020-12-03.
  7. "SN 1983V | Transient Name Server". wis-tns.weizmann.ac.il. Retrieved 2020-12-03.
  8. "Supernova 2001du in NGC 1365". www.rochesterastronomy.org. Retrieved 2020-12-03.
  9. Klotz, A.; Maury, A.; Childress, M.; Zhou, G.; Tucker, B.; Bayliss, D.; Scalzo, R.; Yuan, F.; Schmidt, B.; Buil, C. (2012-10-01). "Supernova 2012fr in NGC 1365 = Psn J03333599-3607377". Central Bureau Electronic Telegrams. 3275: 1. Bibcode:2012CBET.3275....1K.
  10. Reynolds, Christopher (2013). "Astrophysics: Black holes in a spin". Nature. 494 (7438): 432–433. Bibcode:2013Natur.494..432R. doi:10.1038/494432a. PMID 23446411. S2CID 205076505.
  11. - Unambiguous Determination of the Spin of the Black Hole in NGC 1365
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