IC 1459

IC 1459 (also catalogued as IC 5265) 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.[3]

IC 1459
IC 1459 by Hubble Space Telescope
Credit: ESA/NASA
Observation data (J2000 epoch)
ConstellationGrus
Right ascension22h 57m 10.6s[1]
Declination−36° 27′ 44″[1]
Redshift0.006011 ± 0.000039 [1]
Helio radial velocity1,802 ± 12 km/s[1]
Distance85 ± 27 Mly (26.2 ± 8.5 Mpc)[1]
Apparent magnitude (V)10.0 [2]
Characteristics
TypeE3 [1]
Apparent size (V)5′.2 × 3′.8 [1]
Notable featuresRadio galaxy
Other designations
IC 5265, ESO 406- G030, AM 2254-364, MCG -06-50-016, PKS 2254-367, PGC 070090[1]

Characteristics

IC 1459 is a giant elliptical galaxy. In its core has been observed a fast counter-rotating stellar component,[4] with an estimated total mass of 3×109 M☉. The stars of this component have circular orbits on a flat disk with a radius of less than two arcseconds. It has been suggested that the stars of the counterrotating disk are of external origin, either by the accretion of a stellar satellite or of a dense molecular cloud from which the stars were created.[5] The galaxy also features multiple shells and disturbed isophotes, which indicate that it has accreted material, probably by the merger of smaller galaxies with the elliptical galaxy.[6] Enhanced photography revealed the presence of a diffuse spiral pattern at the outer regions of IC 1459.[7]

It has been suggested that a merger started a starburst event in IC 1459. The total duration of this event has not been well constrained, but it is estimated it lasted less than 80 million years. Young stars make up approximately 3% of the total stellar population of the galaxy. They have an average age of 400 million years.[8] Metallicity has been found to decrease as the radial distance from the center increases.[8]

The nucleus of IC 1459 is active and has been characterised as a LINER based on its optical spectrum.[9] The most accepted theory for the power source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole. In the centre of IC 1459 lies a supermassive black hole with an estimated mass (2.6±1.0)×109 M☉ based on stellar velocities.[5] Estimates of the mass of the black hole based on gas kinematics are lower, from (1-4) × 108[10] to 109 M☉, although the presence of non-gravitational forces acting on the circumnuclear gas renders them less accurate.[5] The disturbed kinematics of the circumnuclear gas may be caused by an outflow.[11] In the circumnuclear region there is also dust with irregular distribution, indicating nonequilibrium motions.[12]

The galaxy is characterised as low-power radio loud, with gigahertz-peaked spectrum, and has two symmetrical radio jets.[13] In a 3.5 year observation period, the galaxy showed little variability.[14] The galaxy also has weak X-ray emission. The nucleus appears unabsorbed in lower energy X-ray, with X-ray luminosity 7.9×1040 ergs s-1, while the Fe-Kα fluorescence line, is not strong. The infrared emission of the nucleus is also less than the one expected by an AGN hidden by a dust torus. This indicates that the AGN is seen unobstructed.[15] The galaxy possess an X-ray halo, whose modelling indicated the presence of dark matter at a distance larger than 3 effective radii.[16]

In images by the Hubble Space Telescope, 199 globular clusters were recognised, with an indication of a decrease of their number near the core and statistically non-significant evidence of dimodial color distribution.[17]

Nearby galaxies

IC 1459 is the brightest galaxy in a galaxy group known as the IC 1459 group. It is a loose group centred at IC 1459 with a large number of spiral galaxies.[18] Other members include NGC 7418, NGC 7418A, NGC 7421, IC 5264, IC 5269, IC 5269B, IC 5270, and IC 5273.[19] IC 5264 lies 6.5 arcminutes south of IC 1459. This group, along with the NGC 7582 group form the Grus cloud, a region of elevated galaxy density.[18] The Grus cloud, along with the nearby Pavo-Indus cloud, lies between the Local Supercluster and Pavo-Indus Supercluster.[20]

The group features both diffuse X-ray emission from the intergalactic medium and HI emission. Based on the presence of both it has been suggested that the group is in its early stages of assembling from different subgroups. Three HI clouds have been found to be associated with the group, two located near IC 5270 and one near NGC 7418. These HI clouds are believed to have formed from gas stripped from the galaxies as a result of interactions.[18]

See also

References
  1. "NASA/IPAC Extragalactic Database". Results for IC 1459. Retrieved 2019-01-18.
  2. "Revised IC Data for IC 1459". spider.seds.org. Archived from the original on 24 January 2019. Retrieved 25 November 2018.
  3. Seligman, Courtney. "IC 1459 (= IC 5265 = PGC 70090)". Celestial Atlas. Retrieved 19 November 2018.
  4. Franx, Marijn; Illingworth, Garth D. (April 1988). "A counterrotating core in IC 1459". The Astrophysical Journal. 327: L55. Bibcode:1988ApJ...327L..55F. doi:10.1086/185139.
  5. Cappellari, M.; Verolme, E. K.; van der Marel, R. P.; Kleijn, G. A. Verdoes; Illingworth, G. D.; Franx, M.; Carollo, C. M.; de Zeeuw, P. T. (20 October 2002). "The Counterrotating Core and the Black Hole Mass of IC 1459". The Astrophysical Journal. 578 (2): 787–805. arXiv:astro-ph/0202155. Bibcode:2002ApJ...578..787C. doi:10.1086/342653. S2CID 16983116.
  6. Tal, Tomer; van Dokkum, Pieter G.; Nelan, Jenica; Bezanson, Rachel (1 November 2009). "The Frequency of Tidal Features Associated with Nearby Luminous Elliptical Galaxies From a Statistically Complete Sample". The Astronomical Journal. 138 (5): 1417–1427. arXiv:0908.1382. Bibcode:2009AJ....138.1417T. doi:10.1088/0004-6256/138/5/1417. S2CID 19104100.
  7. Malin, D.F. (1985). "Food for the photometrists — faint galaxies revealed". New aspects of galaxy photometry : proceedings of the specialized meeting of the Eighth IAU European Regional Astronomy Meeting, Toulouse, September 17-21, 1984. Lecture Notes in Physics. 232. Springer-Verlag. p. 28. doi:10.1007/BFb0030917. ISBN 978-3-540-39566-9.
  8. Amblard, A.; Temi, P.; Gaspari, M.; Brighenti, F. (27 December 2016). "Spectral Energy Distribution Mapping of Two Elliptical Galaxies on sub-kpc scales". The Astrophysical Journal. 834 (1): 20. arXiv:1611.00857. doi:10.3847/1538-4357/834/1/20. S2CID 118591820.
  9. Phillips, M. M.; Jenkins, C. R.; Dopita, M. A.; Sadler, E. M.; Binette, L. (May 1986). "Ionized gas in elliptical and S0 galaxies. I - A survey for H-alpha and forbidden N II emission". The Astronomical Journal. 91: 1062. doi:10.1086/114083.
  10. Verdoes Kleijn, Gijs A.; van der Marel, Roeland P.; Carollo, C. Marcella; de Zeeuw, P. Tim (September 2000). "The Black Hole in IC 1459 from Hubble Space Telescope Observations of the Ionized Gas Disk". The Astronomical Journal. 120 (3): 1221–1237. arXiv:astro-ph/0003433. Bibcode:2000AJ....120.1221V. doi:10.1086/301524.
  11. Ricci, T. V.; Steiner, J. E.; Menezes, R. B. (29 June 2015). "IFU spectroscopy of 10 early-type galactic nuclei – III. Properties of the circumnuclear gas emission". Monthly Notices of the Royal Astronomical Society. 451 (4): 3728–3758. arXiv:1506.03459. Bibcode:2015MNRAS.451.3728R. doi:10.1093/mnras/stv1156. S2CID 118568205.
  12. Forbes, Duncan A.; Franx, Marijn; Illingworth, Garth D. (June 1994). "Ellipticals with kinematically distinct cores : HST imaging of the nuclear structure of IC 1459". The Astrophysical Journal. 428: L49. Bibcode:1994ApJ...428L..49F. doi:10.1086/187390.
  13. Tingay, S. J.; Edwards, P. G. (21 March 2015). "The multifrequency parsec-scale structure of PKS 2254−367 (IC 1459): a luminosity-dependent break in morphology for the precursors of radio galaxies?". Monthly Notices of the Royal Astronomical Society. 448 (1): 252–257. arXiv:1501.04393. Bibcode:2015MNRAS.448..252T. doi:10.1093/mnras/stu2756. S2CID 119237931.
  14. Tingay, S. J.; Edwards, P. G.; Tzioumis, A. K. (21 November 2003). "Identification of a new low-redshift GHz-peaked spectrum radio source and implications for the GHz-peaked spectrum class". Monthly Notices of the Royal Astronomical Society. 346 (1): 327–331. Bibcode:2003MNRAS.346..327T. doi:10.1046/j.1365-2966.2003.07098.x.
  15. Fabbiano, G.; Elvis, M.; Markoff, S.; Siemiginowska, A.; Pellegrini, S.; Zezas, A.; Nicastro, F.; Trinchieri, G.; McDowell, J. (May 2003). "The X‐Ray–faint Emission of the Supermassive Nuclear Black Hole of IC 1459". The Astrophysical Journal. 588 (1): 175–185. arXiv:astro-ph/0301297. Bibcode:2003ApJ...588..175F. doi:10.1086/374040. S2CID 17741397.
  16. Samurović, S.; Danziger, I. J. (November 2005). "Dark matter in early-type galaxies: dynamical modelling of IC 1459, IC 3370, NGC 3379 and NGC 4105". Monthly Notices of the Royal Astronomical Society. 363 (3): 769–800. arXiv:astro-ph/0508263. Bibcode:2005MNRAS.363..769S. doi:10.1111/j.1365-2966.2005.09479.x. S2CID 15706248.
  17. Forbes, Duncan A.; Franx, Marijn; Illingworth, Garth D.; Carollo, C. M. (August 1996). "Ellipticals with Kinematically Distinct Cores: WFPC2 Imaging of Globular Clusters". The Astrophysical Journal. 467: 126. arXiv:astro-ph/9604146. Bibcode:1996ApJ...467..126F. doi:10.1086/177589. S2CID 197355.
  18. Serra, P.; et al. (25 July 2015). "ASKAP H i imaging of the galaxy group IC 1459". Monthly Notices of the Royal Astronomical Society. 452 (3): 2680–2691. arXiv:1506.04399. Bibcode:2015MNRAS.452.2680S. doi:10.1093/mnras/stv1326. S2CID 56107758.
  19. 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.
  20. Fouque, P.; Proust, D.; Quintana, H.; Ramirez, A. (September 1993). "Dynamics of the Pavo-Indus and Grus clouds of galaxies". Astronomy and Astrophysics Supplement Series. 100: 493–500. Bibcode:1993A&AS..100..493F. ISSN 0365-0138.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.