NGC 1947

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NGC 1947
Faint remnant threads (50742627743).jpg
NGC 1947 by Hubble Space Telescope
Observation data (J2000 epoch)
Constellation Dorado
Right ascension 05h 26m 47.6s [1]
Declination −63° 45′ 36″ [1]
Redshift 0.003669 ± 0.000080 [1]
Heliocentric radial velocity 1,100 ± 24 km/s [1]
Distance 47.8 ± 11.7 Mly (14.65 ± 3.6 Mpc) [1]
Apparent magnitude  (V)10.8 [2]
Characteristics
Type S0- pec [1]
Apparent size  (V)3.0′ × 2.6′ [1]
Notable featuresPolar-ring
Other designations
ESO 085-G87, AM 0526-634, IRAS 05264-6347, PGC 17296 [1]

NGC 1947 is a peculiar lenticular galaxy in the constellation Dorado. The galaxy lies about 50 million light years away from Earth, which means, given its apparent dimensions, that NGC 1947 is approximately 75,000 light years across. [1] It was discovered by James Dunlop on November 5, 1826. [3]

Contents

Characteristics

The galaxy is characterised by the presence of dust lanes across the minor axis of the galaxy, indicating it is a polar-ring galaxy. [4] The galaxy has one central dust lane while three more less pronounced lanes are visible which look like concentric rings. Although it is categorised as a lenticular galaxy, it lacks a disk, having thus more in common with elliptical galaxies. [5]

Molecular gas has been detected around the nucleus of the galaxy with an estimated hydrogren mass of 4.2×108  M☉ . [6] The gas rotates in an axis perpendicular to that of the stars of the galaxy, but in its inner region it is warped. The kinematics suggest that the dust and gas have an external origin, probably accreted from a gas-rich galaxy, as there is a lack of tidal tails that would indicate it ts as a result of an unequal mass merger with a disk galaxy. [4]

The nucleus of the galaxy has been found to be active and it is categorised as a LINER. [7] The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole.

Nearby galaxies

NGC 1947 is the brightest galaxy in the NGC 1947 group, which also includes the galaxies ESO 085–065, ESO 085–088, and ESO 086–010. This group lies close to the Dorado Group. [8]

Related Research Articles

<span class="mw-page-title-main">Elliptical galaxy</span> Spherical or ovoid mass of stars

An elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth, nearly featureless image. They are one of the four main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work The Realm of the Nebulae, along with spiral and lenticular galaxies. Elliptical (E) galaxies are, together with lenticular galaxies (S0) with their large-scale disks, and ES galaxies with their intermediate scale disks, a subset of the "early-type" galaxy population.

<span class="mw-page-title-main">Lenticular galaxy</span> Class of galaxy between an elliptical galaxy and a spiral galaxy

A lenticular galaxy is a type of galaxy intermediate between an elliptical and a spiral galaxy in galaxy morphological classification schemes. It contains a large-scale disc but does not have large-scale spiral arms. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. They may, however, retain significant dust in their disks. As a result, they consist mainly of aging stars. Despite the morphological differences, lenticular and elliptical galaxies share common properties like spectral features and scaling relations. Both can be considered early-type galaxies that are passively evolving, at least in the local part of the Universe. Connecting the E galaxies with the S0 galaxies are the ES galaxies with intermediate-scale discs.

<span class="mw-page-title-main">Polar-ring galaxy</span> Type of galaxy in which an outer ring of gas and stars rotates over the poles of the galaxy

A polar-ring galaxy is a type of galaxy with an outer ring of gas and stars that rotates over the poles of the galaxy. These polar rings are thought to form when two galaxies gravitationally interact with each other. One possibility is that a material is tidally stripped from a passing galaxy to produce the polar ring. The other possibility is that a smaller galaxy collides orthogonally with the plane of rotation of the larger galaxy, with the smaller galaxy effectively forming the polar-ring structure.

<span class="mw-page-title-main">NGC 1553</span> Galaxy in the constellation Dorado

NGC 1553 is a prototypical lenticular galaxy in the constellation Dorado. It is the second brightest member of the Dorado Group of galaxies. British astronomer John Herschel discovered NGC 1553 on December 5, 1834 using an 18.7 inch reflector.

<span class="mw-page-title-main">NGC 5643</span> Galaxy in the constellation Lupus

NGC 5643 is an intermediate spiral galaxy in the constellation Lupus. Based on the tip of the red-giant branch distance indicator, it is located at a distance of about 40 million light-years. NGC 5643 has an active galactic nucleus and is a type II Seyfert galaxy.

<span class="mw-page-title-main">NGC 5084</span> Galaxy in the constellation Virgo

NGC 5084 is a lenticular galaxy in the constellation of Virgo. It is located at a distance of about 80 million light years from Earth, which, given its apparent dimensions, means that NGC 5084 is at least 200,000 light years across. It is one of the largest and most massive galaxies in the Virgo Supercluster. William Herschel discovered it on March 10, 1785. It is a member of the NGC 5084 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. The galaxy is seen nearly edge-on, with inclination 86°, and features a warped disk and large quantities of HI gas extending along the disk, probably accumulated after multiple accretions of smaller galaxies.

<span class="mw-page-title-main">NGC 612</span> Galaxy in the constellation Sculptor

NGC 612 is a lenticular galaxy in the constellation of Sculptor located approximately 388 million light-years from Earth. It is a type II Seyfert galaxy and thus has an active galactic nucleus. NGC 612 has been identified as an extremely rare example of a non-elliptical radio galaxy, hosting one of the nearest powerful FR-II radio sources.

<span class="mw-page-title-main">NGC 5322</span> Galaxy in the constellation Ursa Major

NGC 5322 is an elliptical galaxy located in the constellation Ursa Major. It is located at a distance of circa 80 million light years from Earth, which, given its apparent dimensions, means that NGC 5322 is about 140,000 light years across. It was discovered by William Herschel on March 19, 1790.

<span class="mw-page-title-main">NGC 5982</span> Galaxy in the constellation Draco

NGC 5982 is an elliptical 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 5982 is about 100,000 light years across. It was discovered by William Herschel on May 25, 1788.

<span class="mw-page-title-main">NGC 6907</span> Galaxy in the constellation Capricornus

NGC 6907 is a spiral galaxy located in the constellation Capricornus. It is located at a distance of about 120 million light-years from Earth, which, given its apparent dimensions, means that NGC 6907 is about 115,000 light-years across. It was discovered by William Herschel on July 12, 1784. The total infrared luminosity of the galaxy is 1011.03 L☉, and thus it is categorised as a luminous infrared galaxy.

<span class="mw-page-title-main">NGC 3489</span> Galaxy in the constellation Leo

NGC 3489 is a lenticular galaxy located in the constellation Leo. It is located at a distance of about 30 million light years from Earth, which, given its apparent dimensions, means that NGC 3489 is about 30,000 light years across. It was discovered by William Herschel on April 8, 1784. NGC 3489 is a member of the Leo Group.

<span class="mw-page-title-main">NGC 3665</span> Galaxy in the constellation Ursa Major

NGC 3665 is a lenticular galaxy located in the constellation Ursa Major. It is located at a distance of circa 85 million light-years from Earth, which, given its apparent dimensions, means that NGC 3665 is about 85,000 light years across. It was discovered by William Herschel on March 23, 1789.

<span class="mw-page-title-main">IC 1459</span> Elliptical galaxy in the constellation of Grus

IC 1459 is an elliptical galaxy located in the constellation Grus. It is located at a distance of circa 85 million light-years from Earth, which, given its apparent dimensions, means that IC 1459 is about 130,000 light-years across. It was discovered by Edward Emerson Barnard in 1892.

<span class="mw-page-title-main">NGC 4278</span> Galaxy in the constellation Coma Berenices

NGC 4278 is an elliptical galaxy located in the constellation Coma Berenices. It is located at a distance of circa 55 million light years from Earth, which, given its apparent dimensions, means that NGC 4278 is about 65,000 light years across. It was discovered by William Herschel on March 13, 1785. NGC 4278 is part of the Herschel 400 Catalogue and can be found about one and 3/4 of a degree northwest of Gamma Comae Berenices even with a small telescope.

<span class="mw-page-title-main">NGC 5363</span> Galaxy in the constellation Virgo

NGC 5363 is a lenticular galaxy located in the constellation Virgo. It is located at a distance of circa 65 million light years from Earth, which, given its apparent dimensions, means that NGC 5363 is about 100,000 light years across. It was discovered by William Herschel on January 19, 1784. It is a member of the NGC 5364 Group of galaxies, itself one of the Virgo III Groups strung out to the east of the Virgo Supercluster of galaxies.

<span class="mw-page-title-main">NGC 2974</span> Galaxy in the constellation Sextans

NGC 2974 is a lenticular galaxy located in the constellation Sextans. It is located at a distance of circa 90 million light years from Earth, which, given its apparent dimensions, means that NGC 2974 is about 90,000 light years across. It was discovered by William Herschel on January 6, 1785. NGC 2974 is located in the sky about 2 and a half degrees south-south east of Iota Hydrae and more than 6 degrees northeast of Alphard. A 10th magnitude star lies next to the galaxy, thus making it a challenging object at low magnifications. NGC 2974 is part of the Herschel 400 Catalogue.

<span class="mw-page-title-main">NGC 3656</span> Peculiar galaxy in the constellation Ursa Major

NGC 3656 is a peculiar galaxy formed by the collision of two galaxies in the constellation of Ursa Major. It is located about 135 million light years away from Earth, which means, given its apparent dimensions, that NGC 3656 is approximately 70,000 light years across. It was discovered by William Herschel on April 14, 1789.

<span class="mw-page-title-main">NGC 7172</span> Galaxy in the constellation of Piscis Austrinus

NGC 7172 is a spiral galaxy located in the constellation Piscis Austrinus. It is located at a distance of about 110 million light years from Earth, which, given its apparent dimensions, means that NGC 7172 is about 100,000 light years across. It was discovered by John Herschel on September 23, 1834.

<span class="mw-page-title-main">NGC 5506</span> Galaxy in the constellation of Virgo

NGC 5506 is a spiral galaxy located in the constellation Virgo. It is located at a distance of about 75 million light years from Earth, which, given its apparent dimensions, means that NGC 5506 is about 80,000 light years across. It was discovered by William Herschel on April 15, 1787. It is a Seyfert galaxy.

<span class="mw-page-title-main">NGC 2911</span>

NGC 2911 is a peculiar lenticular galaxy in the constellation Leo. The galaxy lies about 145 million light years away from Earth, which means, given its apparent dimensions, that NGC 2911 is approximately 165,000 light years across. It was discovered by William Herschel on March 11, 1784.

References

  1. 1 2 3 4 5 6 7 8 9 "NASA/IPAC Extragalactic Database". Results for NGC 1947. Retrieved 2024-03-26.
  2. ↑ "Revised NGC Data for NGC 1947". spider.seds.org. Retrieved 30 March 2024.
  3. ↑ Seligman, Courtney. "NGC 1947 (= PGC 17296 = ESO 085-087)". Celestial Atlas. Retrieved 19 November 2018.
  4. 1 2 Spavone, M.; Iodice, E.; Calvi, R.; Bettoni, D.; Galletta, G.; Longo, G.; Mazzei, P.; Minervini, G. (11 February 2009). "Revisiting the formation history of the minor-axis dust lane galaxy NGC 1947". Monthly Notices of the Royal Astronomical Society. 393 (1): 317–328. doi:10.1111/j.1365-2966.2008.14231.x.
  5. ↑ Bertola, F.; Galetta, G.; Zeilinger, W. W. (1 February 1992). "The minor-axis dust-lane elliptical NGC 1947". Astronomy and Astrophysics. 254: 89–92. ISSN   0004-6361.
  6. ↑ Sage, Leslie J.; Galletta, Giuseppe (December 1993). "Evolution in Dust Lane Ellipticals: Detection of Accreted Molecular Gas". The Astrophysical Journal. 419: 544. doi:10.1086/173507.
  7. ↑ Ricci, T V; Steiner, J E; Menezes, R B; Slodkowski Clerici, K; da Silva, M D (21 April 2023). "The DIVING3D Survey – Deep IFS View of Nuclei of Galaxies – III. Analysis of the nuclear region of the early-type galaxies of the sample". Monthly Notices of the Royal Astronomical Society. 522 (2): 2207–2222. doi:10.1093/mnras/stad1130.
  8. ↑ 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. Archived from the original on 31 January 2016. Retrieved 20 March 2017.
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