NGC 5701 is a barred lenticular galaxy with a ring located in the constellation Virgo. It lies at a distance of about 50 million light years from Earth based on redshift-independent methods, which, given its apparent dimensions, means that NGC 5701 is about 65,000 light years across.[1] Based on redshift the galaxy lies at a distance of 85 million light years.[1] It was discovered by William Herschel on April 29, 1786.[3]

Characteristics

Central region

The galaxy is categorised as a barred lenticular galaxy. The bar is faint and diffuse,[4] and almost completely dust-free.[5] At its ends it has elevated brightness, forming ansae.[6] It surrounds a large, bright and slightly elliptical bulge with a bright nucleus. The bar lies inside a disk which mostly lacks features, with the exception of some knots or possible companion galaxies.[4] The bar is strong and dominates the disk, while the bulge component could overlap with the disk, making the galaxy appear to lack a disk.[7] The lack of disk however could be the result of a model that lacks the bar as different models indicate the presence of the disk.[8] An inner ring is detectable at the end of the bar.[7]

The stellar population in the barlens is mostly old, as 70–85% of the stellar mass is older than 10 billion years.[9] The intermediate age stars are more common at the outer edges of the barlens.[10] The bar doesn't show to induse star formation. At the centre the metallicity is solar and becomes subsolar towards the edges, and is higher than that of the bulge of the Milky Way.[9] Gas and stellar velocity fields are slightly offset with each other as indicated by the position angles of their major axes.[11] The isophotes indicate that the bar is also misaligned with the stellar velocity field.[10]

The nucleus of the galaxy has been found to be active and based on its emission lines has been identified as a transitional object between an HII region and a LINER.[12] The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole. The mass of the black hole in the centre of NGC 5701 is estimated to be 107.9 (80 million) M☉ based on the absolute bulge magnitude.[13]

A faint nuclear spiral is visible in images by the Hubble Space Telescope extending to about 10 arcseconds. As the galaxy is seen nearly face-on it is difficult to detect if an inner disk is present.[5] The nuclear spiral is associated with young stars, whose presence however is negligible as far as the total stellar mass of the bulge is concerned.[10]

Outer ring

The galaxy in ultraviolet as observed by GALEX, with the ring glowing blue.

The galaxy has an outer pseudo-ring which is more visible in blue light.[14] The ring is created by two arms which emerge from the end of the disk, but they start to branch into smaller arms, creating a ring of multiple fragmented arms.[6] Many HII regions emitting H-alpha are visible in it, indicating it is a location of active star formation.[15] The ring is detached from the disk and gives the galaxy an appearance similar to Hoag's Object. It is possible that the bar prevents the gas infalling to the central region of the galaxy.[16] The ring is elongated perpendicularly to the bar.[5]

Hydrogen disk

The optical disk is surrounded by a hydrogen envelope which extends to over 10 arcminutes from the nucleus, about two and half times more than the optical edge of the galaxy. The HI emission is about twice as strong at the west of the galaxy than the east but its western edge is sharper. The asymmetry could be the result of a past interaction with another galaxy.[17] Observations by the Arecibo Observatory revealed an HI cloud about 15 arcminutes northwest of the centre[18] but it wasn't detected in observations by the Very Large Array.[17]

Nearby galaxies

NGC 5701 is according to A. M. Garcia a member of the NGC 5746 Group, also known as LGG 386.[19] No companion galaxies are visible in hydrogen line or optical observations. UGC 9385, another member of the group, lies about 56 arcminutes to the west.[17] The group is a member of the Virgo III Groups, a long chain of galaxies extending for about 40 million light years from the Virgo Cluster.[20]

References

  1. ^ a b c d e f g h i j k "NASA/IPAC Extragalactic Database". Results for NGC 5701. Retrieved 2025-03-18.
  2. ^ "Revised NGC Data for NGC 5701". spider.seds.org. Retrieved 30 March 2024.
  3. ^ Seligman, Courtney. "NGC 5701". Celestial Atlas. Retrieved 19 November 2018.
  4. ^ a b Eskridge, Paul B.; Frogel, Jay A.; Pogge, Richard W.; Quillen, Alice C.; Berlind, Andreas A.; Davies, Roger L.; DePoy, D. L.; Gilbert, Karoline M.; Houdashelt, Mark L.; Kuchinski, Leslie E.; Ramirez, Solange V.; Sellgren, K.; Stutz, Amelia; Terndrup, Donald M.; Tiede, Glenn P. (November 2002). "Near-Infrared and Optical Morphology of Spiral Galaxies". The Astrophysical Journal Supplement Series. 143 (1): 73–111. arXiv:astro-ph/0206320. Bibcode:2002ApJS..143...73E. doi:10.1086/342340.
  5. ^ a b c Erwin, Peter; Sparke, Linda S. (June 2003). "An Imaging Survey of Early-Type Barred Galaxies". The Astrophysical Journal Supplement Series. 146 (2): 299–352. arXiv:astro-ph/0212092. Bibcode:2003ApJS..146..299E. doi:10.1086/367885.
  6. ^ a b Sandage, A., Bedke, J. (1994), The Carnegie Atlas of Galaxies. Volume I, Carnegie Institution of Washington
  7. ^ a b Gadotti, D. A.; de Souza, R. E. (1 February 2003). "NGC 4608 and NGC 5701: Barred Galaxies without Disks?". The Astrophysical Journal. 583 (2): L75 – L78. arXiv:astro-ph/0301072. Bibcode:2003ApJ...583L..75G. doi:10.1086/368159.
  8. ^ Alexei Gadotti, Dimitri (February 2008). "Image decomposition of barred galaxies and AGN hosts". Monthly Notices of the Royal Astronomical Society. 384 (1): 420–439. arXiv:0708.3870. Bibcode:2008MNRAS.384..420G. doi:10.1111/j.1365-2966.2007.12723.x.
  9. ^ a b Laurikainen, E.; Salo, H. (February 2017). "Barlenses and X-shaped features compared: two manifestations of boxy/peanut bulges". Astronomy & Astrophysics. 598: A10. arXiv:1609.01936. Bibcode:2017A&A...598A..10L. doi:10.1051/0004-6361/201628936.
  10. ^ a b c Seidel, M. K.; Cacho, R.; Ruiz-Lara, T.; Falcón-Barroso, J.; Pérez, I.; Sánchez-Blázquez, P.; Vogt, F. P. A.; Ness, M.; Freeman, K.; Aniyan, S. (21 January 2015). "Dissecting galactic bulges in space and time – I. The importance of early formation scenarios versus secular evolution". Monthly Notices of the Royal Astronomical Society. 446 (3): 2837–2860. doi:10.1093/mnras/stu2295.
  11. ^ Seidel, M. K.; Falcón-Barroso, J.; Martínez-Valpuesta, I.; Díaz-García, S.; Laurikainen, E.; Salo, H.; Knapen, J. H. (21 July 2015). "The BaLROG project – I. Quantifying the influence of bars on the kinematics of nearby galaxies". Monthly Notices of the Royal Astronomical Society. 451 (1): 936–973. doi:10.1093/mnras/stv969.
  12. ^ Ho, Luis C.; Filippenko, Alexei V.; Sargent, Wallace L. W. (October 1997). "A Search for Dwarf Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies". The Astrophysical Journal Supplement Series. 112 (2): 315–390. arXiv:astro-ph/9704107. Bibcode:1997ApJS..112..315H. doi:10.1086/313041.
  13. ^ Dong, X. Y.; De Robertis, M. M. (March 2006). "Low-Luminosity Active Galaxies and Their Central Black Holes". The Astronomical Journal. 131 (3): 1236–1252. arXiv:astro-ph/0510694. Bibcode:2006AJ....131.1236D. doi:10.1086/499334.
  14. ^ Laurikainen, Eija; Salo, Heikki; Buta, Ronald; Vasylyev, Sergiy (December 2004). "Bar-induced perturbation strengths of the galaxies in the Ohio State University Bright Galaxy Survey - I". Monthly Notices of the Royal Astronomical Society. 355 (4): 1251–1271. arXiv:astro-ph/0409503. Bibcode:2004MNRAS.355.1251L. doi:10.1111/j.1365-2966.2004.08410.x.
  15. ^ Pogge, Richard W.; Eskridge, Paul B. (October 1993). "Star formation in the disks of H I-rich S0 galaxies". The Astronomical Journal. 106: 1405. Bibcode:1993AJ....106.1405P. doi:10.1086/116735.
  16. ^ Cortese, L.; Hughes, T. M. (11 December 2009). "Evolutionary paths to and from the red sequence: star formation and H i properties of transition galaxies at z ∼ 0". Monthly Notices of the Royal Astronomical Society. 400 (3): 1225–1240. arXiv:0908.3564. Bibcode:2009MNRAS.400.1225C. doi:10.1111/j.1365-2966.2009.15548.x.
  17. ^ a b c Kornreich, David A.; Haynes, Martha P.; Lovelace, R. V. E.; van Zee, Liese (July 2000). "Departures From Axisymmetric Morphology and Dynamics in Spiral Galaxies". The Astronomical Journal. 120 (1): 139–164. arXiv:astro-ph/0004113. Bibcode:2000AJ....120..139K. doi:10.1086/301422.
  18. ^ Duprie, Kimberly; Schneider, Stephen E. (September 1996). "Neutral Hydrogen Around Early-Type Galaxies". The Astronomical Journal. 112: 937. Bibcode:1996AJ....112..937D. doi:10.1086/118067.
  19. ^ 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.
  20. ^ "The Virgo III Groups". www.atlasoftheuniverse.com. Retrieved 18 March 2025.
Allikas: https://en.wikipedia.org/wiki/NGC_5701
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