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NGC 3445

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NGC 3445
Observation data (J2000 epoch)
ConstellationUrsa Major
Right ascension10h 54m 35.5s[1]
Declination+56° 59′ 26″[1]
Redshift0.006831 ± 0.000003 [1]
Heliocentric radial velocity2,048 ± 1 km/s[1]
Distance73.8 ± 20.1 Mly (22.6 ± 6.2 Mpc)[1]
Apparent magnitude (V)12.3[2]
Characteristics
TypeSAB(s)m [1]
Apparent size (V)1.6 × 1.5[1]
Notable featuresInteracting galaxy
Other designations
UGC 6021, Arp 24, VV 14a, MCG +10-16-023, IRAS 10515+5715, PGC 32772, 7C 1051+5715

NGC 3445 is a Magellanic spiral galaxy in the constellation Ursa Major. The galaxy lies about 75 million light years away from Earth, which means, given its apparent dimensions, that NGC 3445 is approximately 35,000 light years across.[1] It was discovered by William Herschel on April 8, 1793.[3]

Characteristics

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The galaxy is included in Halton Arp's Atlas of Peculiar Galaxies in the one-armed spiral galaxies category. The galaxy has a thick arm pattern with many HII regions.[4] A large spiral arm is visible at the south part of the galaxy while a weaker one is visible in infrared at the north. Radio emission is observed along the arms.[5] At the end of the main spiral arm there is a smaller galaxy, lying 1.2 arcminutes from the nucleus of NGC 3445,[4] connected with a weak bridge.[6]

In the infrared are visible four bright locations of active star formation. The brightest of these infrared knots hosts five young massive star clusters, all being formed by a single giant molecular cloud. The age of the clusters was determined to be 3 to 5 million years and their mass to be around 105 M.[7] Another large star cluster lies at the nucleus of the galaxy and could be in the process of forming a bulge.[5] The total star formation rate of the galaxy is estimated to be around 1 M per year.[5] The star formation as well as the shape of the galaxy could be the result of interaction with other galaxies.[7]

Nearby galaxies

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NGC 3445 forms a triplet with NGC 3440, which lies 9.9 arcminutes away, and NGC 3458, which lies 14 arcminutes away.[4] These galaxies comprise the LGG 226 group.[8] It belongs to the same galaxy cloud as NGC 3610.[9]

References

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  1. ^ a b c d e f g h "NASA/IPAC Extragalactic Database". Results for NGC 3445. Retrieved 2024-03-26.
  2. ^ "Revised NGC Data for NGC 3445". spider.seds.org. Retrieved 30 March 2024.
  3. ^ Seligman, Courtney. "NGC 3445 (= Arp 24)". Celestial Atlas. Retrieved 19 November 2018.
  4. ^ a b c Sandage, A., Bedke, J. (1994), The Carnegie Atlas of Galaxies. Volume I, Carnegie Institution of Washington
  5. ^ a b c Das, M.; Sengupta, C.; Ramya, S.; Misra, K. (11 July 2012). "Star formation in bulgeless late-type galaxies: clues to their evolution: Star formation in bulgeless galaxies". Monthly Notices of the Royal Astronomical Society. 423 (4): 3274–3284. arXiv:1205.1936. doi:10.1111/j.1365-2966.2012.21120.x.
  6. ^ Smith, Beverly J.; Struck, Curtis; Hancock, Mark; Appleton, Philip N.; Charmandaris, Vassilis; Reach, William T. (March 2007). "The Spitzer Spirals, Bridges, and Tails Interacting Galaxy Survey: Interaction-Induced Star Formation in the Mid-Infrared". The Astronomical Journal. 133 (3): 791–817. arXiv:astro-ph/0610562. Bibcode:2007AJ....133..791S. doi:10.1086/510350.
  7. ^ a b Cao, Chen; Wu, Hong (April 2007). "Multiwavelength Study of Young Massive Star Clusters in the Interacting Galaxy Arp 24". The Astronomical Journal. 133 (4): 1710–1721. arXiv:astro-ph/0612724. Bibcode:2007AJ....133.1710C. doi:10.1086/512125.
  8. ^ Garcia, A. M. (1 July 1993). "General study of group membership. II. Determination of nearby groups". Astronomy and Astrophysics Supplement Series. 100: 47–90. Bibcode:1993A&AS..100...47G. ISSN 0365-0138.
  9. ^ Makarov, Dmitry; Karachentsev, Igor (21 April 2011). "Galaxy groups and clouds in the local (z~ 0.01) Universe". Monthly Notices of the Royal Astronomical Society. 412 (4): 2498–2520. arXiv:1011.6277. Bibcode:2011MNRAS.412.2498M. doi:10.1111/j.1365-2966.2010.18071.x. S2CID 119194025.
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