Cannabaceae

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NGC 1705
NGC 1705. Credit: NASA.
Observation data (J2000 epoch)
ConstellationPictor
Right ascension04h 54m 13.500s[1]
Declination−53° 21′ 39.82″[1]
Redshift633 ± 6 km/s[2]
Distance16.6 ± 2.0 Mly (5.1 ± 0.6 Mpc)[3]
Group or clusterDorado Group
Apparent magnitude (V)12.56±0.03[4]
Characteristics
TypeSA0− pec[2] or BCD[3]
Apparent size (V)1′.86 × 1′.45[5]
Other designations
PGC 16282[2]

NGC 1705 is a peculiar lenticular galaxy and a blue compact dwarf galaxy (BCD)[3] in the southern constellation of Pictor, positioned less than a degree to the east of Iota Pictoris,[6] and is undergoing a starburst.[7] With an apparent visual magnitude of 12.6[4] it requires a telescope to observe. It is estimated to be approximately 17 million light-years from the Earth,[8] and is a member of the Dorado Group.[9]

This is a relatively isolated galaxy, with its nearest neighbors being more than 500 kpc distant. However, its neutral hydrogen disk shows a significant amount of warp, suggesting that the outer gas is still settling into place.[3] The mass models of the galaxy suggest the dominant source of mass is a dark matter halo.[10] It has a super star cluster located near the galactic center,[10] and shows strong galactic winds.[3] Designated NGC1750–1, this cluster has a maximum radius of 2.85±0.50 pc and is 12±6 Myr old.[11]

The major starburst activity is happening at the core of the galaxy, within the central ~150 pc, and this is providing the main ionizing source out to distance of ~1 kpc or more.[7] Over the last 10 million years it has added 5.7×105 M☉ worth of stars.[3] The younger stars in the galaxy with an age below a billion years have an estimated 6×107 M☉ and are mainly concentrated near the center, while the older star populations have 2.2×108 M☉ and form a more extended distribution. The total mass of neutral hydrogen in the galaxy is estimated at (2.2±0.2)×108 M☉.[10]

References

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  1. ^ a b Skrutskie, Michael F.; Cutri, Roc M.; Stiening, Rae; Weinberg, Martin D.; Schneider, Stephen E.; Carpenter, John M.; Beichman, Charles A.; Capps, Richard W.; Chester, Thomas; Elias, Jonathan H.; Huchra, John P.; Liebert, James W.; Lonsdale, Carol J.; Monet, David G.; Price, Stephan; Seitzer, Patrick; Jarrett, Thomas H.; Kirkpatrick, J. Davy; Gizis, John E.; Howard, Elizabeth V.; Evans, Tracey E.; Fowler, John W.; Fullmer, Linda; Hurt, Robert L.; Light, Robert M.; Kopan, Eugene L.; Marsh, Kenneth A.; McCallon, Howard L.; Tam, Robert; Van Dyk, Schuyler D.; Wheelock, Sherry L. (1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal. 131 (2): 1163–1183. Bibcode:2006AJ....131.1163S. doi:10.1086/498708. ISSN 0004-6256. S2CID 18913331.
  2. ^ a b c "NASA/IPAC Extragalactic Database". Results for NGC 1705. Retrieved 2006-11-29.
  3. ^ a b c d e f Cignoni, M.; et al. (March 2018). "Star Formation Histories of the LEGUS Dwarf Galaxies. I. Recent History of NGC 1705, NGC 4449, and Holmberg II". The Astrophysical Journal. 856 (1): 17. arXiv:1802.06792. Bibcode:2018ApJ...856...62C. doi:10.3847/1538-4357/aab041. S2CID 119485664. 62.
  4. ^ a b Cook, David O.; et al. (2014). "Spitzer Local Volume Legacy (LVL) SEDs and physical properties". Monthly Notices of the Royal Astronomical Society. 445 (1): 899–912. arXiv:1409.0847. Bibcode:2014MNRAS.445..899C. doi:10.1093/mnras/stu1787.
  5. ^ Paturel, G.; et al. (December 2003). "HYPERLEDA. I. Identification and designation of galaxies". Astronomy and Astrophysics. 412: 45–55. Bibcode:2003A&A...412...45P. doi:10.1051/0004-6361:20031411.
  6. ^ Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. Vol. 1. Sky Publishing Corporation and the European Space Agency. p. 458. ISBN 0-933346-84-0.
  7. ^ a b Annibali, F.; et al. (November 2015). "Chemical Abundances and Properties of the Ionized Gas in NGC 1705". The Astronomical Journal. 150 (5): 23. arXiv:1505.05545. Bibcode:2015AJ....150..143A. doi:10.1088/0004-6256/150/5/143. S2CID 119249162. 143.
  8. ^ Nemiroff, R. & Bonnell, J., eds. (April 23, 2003). "The Stars of NGC 1705". Astronomy Picture of the Day. NASA.
  9. ^ Huchra, J. P.; Geller, M. J. (June 15, 1982). "Groups of galaxies. I - Nearby groups". Astrophysical Journal. 257 (Part 1): 423–437. Bibcode:1982ApJ...257..423H. doi:10.1086/160000.
  10. ^ a b c Elson, E. C.; et al. (March 2013). "H I synthesis observations of the blue compact dwarf NGC 1705". Monthly Notices of the Royal Astronomical Society. 429 (3): 2550–2561. arXiv:1301.2889. Bibcode:2013MNRAS.429.2550E. doi:10.1093/mnras/sts526.
  11. ^ Martins, F.; et al. (November 2012). "Near-infrared spectroscopy of the super star cluster in NGC 1705". Astronomy & Astrophysics. 547: 4. arXiv:1209.3910. Bibcode:2012A&A...547A..17M. doi:10.1051/0004-6361/201220144. S2CID 56159879. A17.
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source: https://en.wikipedia.org/wiki/NGC_1705

One thought on “Cannabaceae”

  1. Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
    View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction

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