NGC 7720

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NGC 7720
NGC7720 - SDSS DR14.jpg
NGC 7720 by PanSTARRS
Observation data (J2000 epoch)
Constellation Pegasus
Right ascension 23h 38m 29.4s [1]
Declination +27° 01′ 53″ [1]
Redshift 0.030221 ± 0.000047 [1]
Helio radial velocity 9,060 ± 14 km/s [1]
Distance 385 ± 63 Mly (118 ± 19.3 Mpc) [1]
Apparent magnitude  (V)12.6 [2]
Characteristics
Type cD;E+ pec [1]
Apparent size  (V)1.6′ × 1.3′ [1]
Notable featuresRadio galaxy
Other designations
UGC 12716, CGCG 476-091, MCG +04-55-036, 3C 465, 4C +26.64, PGC 71985 [1]

NGC 7720 is an elliptical galaxy located in the constellation Pegasus. It is located at a distance of about 380 million light years from Earth, which, given its apparent dimensions, means that NGC 7720 is about 180,000 light years across. [1] NGC 7720 is the main galaxy of Abell 2634 galaxy cluster and is a radio galaxy. It was discovered by William Herschel on September 10, 1784. [3]

Contents

Characteristics

The central region of NGC 7720, with the two dust disks, by the Hubble Space Telescope. NGC 7720 cutout hst 06967 4w wfpc2 total pc sci.jpg
The central region of NGC 7720, with the two dust disks, by the Hubble Space Telescope.

NGC 7720 is made of a galaxy pair that is separated by 12 arcseconds. The south galaxy is the one associated with the radio source. In the centre of the galaxy lies a dust disk is visible nearly face on. The dust mass of NGC 7720 is estimated to be between 106 to 107  M☉ . There is also ionized Hα+[N II] gas emission from the disk. [4] NGC 7720A features too a dusty disk. [4]

Radio jet

The radio jets of NGC 7720 by the Very Large Array. NGC 7720 NVAS 4.93I3.53 AE0061 1989OCT01 1 631.U4.52M.jpg
The radio jets of NGC 7720 by the Very Large Array.

NGC 7720 is a Fanaroff-Riley type I radio galaxy, and is also categorised as a wide angle tail (WAT) radio galaxy. It has two asymmetrical radio jets that emerge from the bright radio core. The core didn't exhibit variability when observed by the Very Large Array (VLA). [5] In parsec scales, the jet is one sided features relativistic motion, about 0.6 times the speed of light, and has a northwest direction. [6]

The northwest jet is the main one and forms a distorted plume about 5 arcminutes long, with a hotspot about 30 arcseconds from the core. The southeastern jet has a bright spot about 30 arcseconds from the core and then fans to a distorted plume that extends for 5 arcminutes. [6] [5] In large scales the jets appear bend, maybe due to ram pressure as the galaxy moves through the intracluster medium. [7]

X-ray emission has been detected by the radio jet, indicating the contribution of synchroton mechanism to the creation of the jet. The radio plumes are regions with decreased X-ray emission. [8]

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 7720 is estimated to be 109.28 (1.9 billion) M☉ based on stellar velocity dispersion or 109.26 (1.81 billion) M☉ based on mass of the bulge. [9]

Nearby galaxies

NGC 7720 is the dominant galaxy in Abell 2634 galaxy cluster. It is classified as a poor galaxy cluster and has a total X-ray luminosity of (1.4±0.3)×1044 erg/s, which is considered low in relation to other similar clusters. X-ray bolometric luminosity has a central peak which corresponds to NGC 7720, while excess emission is to the southwest, perpendicularly to the radio jets. [10]

About 118 galaxies lie within half degree from the centre of the cluster and are considered to be members of the cluster. Abell 2634 forms a pair with galaxy cluster Abell 2666, which is located 3 degrees to the east, but has lower redshift. Both clusters lie behind the Perseus–Pisces Supercluster. Abell 2622 lies behind Abell 2634, at about double the redshift. [11]

See also

Related Research Articles

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<span class="mw-page-title-main">Radio galaxy</span> Type of active galaxy that is very luminous at radio wavelengths

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<span class="mw-page-title-main">Antlia Cluster</span> Galaxy cluster in the constellation Antlia

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<span class="mw-page-title-main">NGC 4698</span> Galaxy in the constellation Virgo

NGC 4698 is a barred spiral galaxy located around 55 million light years away from Earth in the constellation of Virgo. It belongs to the Virgo Cluster of galaxies and is positioned near the northeastern edge of this assemblage. The morphological classification of NGC 4698 in the De Vaucouleurs system is SA(s)ab, which indicates a purely spiral structure with moderate to tightly wound arms. It is inclined to the line of sight from the Earth by an angle of 53° along a position angle of 170°.

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

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<span class="mw-page-title-main">NGC 708</span> Galaxy in the constellation Andromeda

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<span class="mw-page-title-main">NGC 7469</span> Galaxy located in the constellation Pegasus

NGC 7469 is an intermediate spiral galaxy in the constellation of Pegasus. NGC 7469 is located about 200 million light-years away from Earth, which means, given its apparent dimensions, that NGC 7469 is approximately 90,000 light-years across. It was discovered by William Herschel on November 12, 1784.

<span class="mw-page-title-main">NGC 3367</span> Spiral galaxy in the constellation Leo

NGC 3367 is a barred spiral galaxy located in the constellation Leo. It is located at a distance of about 120 million light years from Earth, which, given its apparent dimensions, means that NGC 3367 is about 85,000 light years across. It was discovered by William Herschel on March 19, 1784.

<span class="mw-page-title-main">NGC 541</span> Galaxy in the constellation Cetus

NGC 541 is a lenticular galaxy located in the constellation Cetus. It is located at a distance of circa 230 million light years from Earth, which, given its apparent dimensions, means that NGC 541 is about 130,000 light years across. It was discovered by Heinrich d'Arrest on October 30, 1864. It is a member of the Abell 194 galaxy cluster and is included in the Atlas of Peculiar Galaxies in the category galaxies with nearby fragments. NGC 541 is a radio galaxy of Fanaroff-Riley class I, also known as 3C 40A.

<span class="mw-page-title-main">NGC 7130</span> Galaxy in the constellation Piscis Austrinus

NGC 7130 is a spiral galaxy located in the constellation Piscis Austrinus. It is located at a distance of about 220 million light years from Earth, which, given its apparent dimensions, means that NGC 7130 is about 100,000 light years across. It was discovered by John Herschel on September 25, 1834, and discovered independently by Lewis Swift on September 17, 1897. The location of the galaxy given in the New General Catalogue was off by 30 arcminutes in declination from the location of the galaxy.

<span class="mw-page-title-main">NGC 1380</span> Galaxy in the constellation Fornax

NGC 1380 is a lenticular galaxy located in the constellation Fornax. It is located at a distance of circa 60 million light years from Earth, which, given its apparent dimensions, means that NGC 1380 is about 85,000 light years across. It was discovered by James Dunlop on September 2, 1826. It is a member of the Fornax Cluster.

<span class="mw-page-title-main">NGC 1386</span> Galaxy in the constellation Eridanus

NGC 1386 is a spiral galaxy located in the constellation Eridanus. It is located at a distance of circa 53 million light years from Earth, which, given its apparent dimensions, means that NGC 1386 is about 50,000 light years across. It is a Seyfert galaxy, the only one in Fornax Cluster.

<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 545</span> Galaxy in the constellation Cetus

NGC 545 is a lenticular galaxy located in the constellation Cetus. It is located at a distance of circa 250 million light years from Earth, which, given its apparent dimensions, means that NGC 545 is about 180,000 light years across. It was discovered by William Herschel on October 1, 1785. It is a member of the Abell 194 galaxy cluster and is included along with NGC 547 in the Atlas of Peculiar Galaxies.

<span class="mw-page-title-main">NGC 547</span> Galaxy in the constellation Cetus

NGC 547 is an elliptical galaxy and radio galaxy located in the constellation Cetus. It is located at a distance of circa 220 million light years from Earth, which, given its apparent dimensions, means that NGC 547 is about 120,000 light years across. It was discovered by William Herschel on October 1, 1785. It is a member of the Abell 194 galaxy cluster and is included along with NGC 547 in the Atlas of Peculiar Galaxies.

<span class="mw-page-title-main">NGC 2273</span> Galaxy in the constellation Lynx

NGC 2273 is a barred spiral galaxy located in the constellation Lynx. It is located at a distance of circa 95 million light years from Earth, which, given its apparent dimensions, means that NGC 2273 is about 100,000 light years across. It was discovered by Nils Dunér on September 15, 1867.

References

  1. 1 2 3 4 5 6 7 8 9 "NASA/IPAC Extragalactic Database". Results for NGC 7720. Retrieved 2023-07-07.
  2. ↑ "Revised NGC Data for NGC 7720". spider.seds.org. Retrieved 25 November 2018.
  3. ↑ Seligman, Courtney. "NGC 7720 (= PGC 71985)". Celestial Atlas. Retrieved 19 November 2018.
  4. 1 2 Martel, A. R.; Ford, H. C.; Bradley, L. D.; Tran, H. D.; Menanteau, F.; Tsvetanov, Z. I.; Illingworth, G. D.; Hartig, G. F.; Clampin, M. (December 2004). "Dust and Ionized Gas in Nine Nearby Early-Type Galaxies Imaged with the Hubble Space Telescope Advanced Camera for Surveys". The Astronomical Journal. 128 (6): 2758–2771. arXiv: astro-ph/0411148 . Bibcode:2004AJ....128.2758M. doi:10.1086/425628. S2CID   204934231.
  5. 1 2 Bempong-Manful, E; Hardcastle, M J; Birkinshaw, M; Laing, R A; Leahy, J P; Worrall, D M (21 July 2020). "A high-resolution view of the jets in 3C 465". Monthly Notices of the Royal Astronomical Society. 496 (1): 676–688. doi:10.1093/mnras/staa1471.
  6. 1 2 Venturi, T.; Castaldini, C.; Cotton, W. D.; Feretti, L.; Giovannini, G.; Lara, L.; Marcaide, J. M.; Wehrle, A. E. (December 1995). "VLBI Observations of a Complete Sample of Radio Galaxies. VI. The Two FR I Radio Galaxies B2 0836+29 and 3C 465". The Astrophysical Journal. 454: 735. arXiv: astro-ph/9506115 . Bibcode:1995ApJ...454..735V. doi:10.1086/176525. S2CID   10260930.
  7. ↑ Sakelliou, Irini; Merrifield, Michael R. (May 1999). "The distorted jets and gaseous environment of 3C 465". Monthly Notices of the Royal Astronomical Society. 305 (2): 417–424. Bibcode:1999MNRAS.305..417S. doi:10.1046/j.1365-8711.1999.02427.x.
  8. ↑ Hardcastle, M. J.; Sakelliou, I.; Worrall, D. M. (May 2005). "A Chandra and XMM-Newton study of the wide-angle tail radio galaxy 3C 465". Monthly Notices of the Royal Astronomical Society. 359 (3): 1007–1021. arXiv: astro-ph/0502575 . Bibcode:2005MNRAS.359.1007H. doi:10.1111/j.1365-2966.2005.08966.x. S2CID   119342523.
  9. ↑ Bettoni, D.; Falomo, R.; Fasano, G.; Govoni, F. (March 2003). "The black hole mass of low redshift radiogalaxies". Astronomy & Astrophysics. 399 (3): 869–878. arXiv: astro-ph/0212162 . Bibcode:2003A&A...399..869B. doi:10.1051/0004-6361:20021869. S2CID   16412006.
  10. ↑ Schindler, S.; Prieto, M. A. (1 November 1997). "X-ray analysis of Abell 2634 and its central galaxy 3C 465". Astronomy and Astrophysics. 327: 37–46. arXiv: astro-ph/9706239 . Bibcode:1997A&A...327...37S. ISSN   0004-6361.
  11. ↑ Scodeggio, Marco; Solanes, Jose M.; Giovanelli, Ricardo; Haynes, Martha P. (May 1995). "The spatial distribution, kinematics, and dynamics of the galaxies in the region of Abell 2634 and 2666". The Astrophysical Journal. 444: 41. arXiv: astro-ph/9409006 . Bibcode:1995ApJ...444...41S. doi:10.1086/175581. S2CID   18035115.
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