NGC 1705

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]
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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]

  1. ^ a b Cite error: The named reference Skrutskie2006 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference ned was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference Cignoni2018 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Cook2014 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Paturel2003 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Sinnott1997 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Annibali2015 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference apod2003 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Huchraetal1982 was invoked but never defined (see the help page).
  10. ^ a b c Cite error: The named reference Elson2013 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Martins2012 was invoked but never defined (see the help page).