PKS 0634-20
| PKS 0634-20 | |
|---|---|
 The radio galaxy PKS 0634-20. | |
| Observation data (J2000 epoch) | |
| Constellation | Canis Major |
| Right ascension | 06h 36m 32.25s[1] |
| Declination | −20° 34′ 53.14″[1] |
| Redshift | 0.056456[1] |
| Heliocentric radial velocity | 16,925 km/s[1] |
| Distance | 753 Mly |
| Apparent magnitude (V) | 17.58 |
| Apparent magnitude (B) | 18.27 |
| Characteristics | |
| Type | E NLRG[1] |
| Size | ~184,400 ly (56.53 kpc) (estimated)[1] |
| Other designations | |
| 2MASX J06363227-2034532, IRAS 06343-2032, 6dF J0636323-203453, PGC 19313, PKS B0634-205, PKS J0636-2036, Cul 0634-205, 0634-20[1] | |
PKS 0634-20 is a powerful Fanaroff-Riley class Type II radio galaxy[2] located in the constellation of Canis Major. It has a redshift of (z) 0.056[1] and was first discovered by astronomers who were conducting the Parkes catalogue survey at Parkes Observatory in 1964.[3] This object is also classified as a Type 2 Seyfert galaxy.[4]
Description
[edit]PKS 0634-20 is classified as a giant radio galaxy with a complex radio structure. When imaged with a 21 centimeter radio map, the structure is best described as a double-triple made up of seven components with an unresolved southern bright component.[5] Observations made by the Westerbork Synthesis Radio Telescope found the outer edges of two components have a separation gap of 14 arcseconds. In addition, the components are narrow and configured, similar to 3C 236.[6]
Observations made with the Effelsberg 100-m Radio Telescope and Very Large Array, discovered there is a long radio emission bridge in PKS 0634-20. When imaged, the bridge is found extending to the outer collinear hotspots with its polarization degree varying from 8% to 30%. When travelling a far distance in terms of projection, there is a change in which the bridge becomes narrower and the polarization degree increases. Results also showed the hotspots located at north and south directions have polarization percentages of 5% and 20%. As mapping at 4".5 resolution also showed the same thing, this suggests either beam cancellation of the northern sub-parts of the hotspot or differential Faraday rotation.[7] Imaging at high resolutions by the Australia Telescope Compact Array also showed the south hotspot has a significant sub-structure.[8]
The host of PKS 0634-20 is a normal elliptical galaxy lying in the poor cluster environment.[2][9] According to imaging by the Anglo-Australian Telescope, the appearance of the galaxy is described as peculiar with a sign of a filamentary structure showing an extension into a northwest quadrant.[10] There is an emission line nebula extending by 20 kiloparsecs from its central nucleus with molecular gas estimated to be 3 x 109 Mʘ. As its mass is greater than the warm gas in the galaxy, this indicates the nebula is radiation-bound. The large quantity of gas is believed to be acquired from either a spiral or a gas-rich galaxy.[11]
Strong doubly ionized oxygen narrow emission lines has been identified in the spectra of PKS 0634-20 with an extent of 70 kiloparsecs along its radio axis.[10] Astronomers also suggested the galaxy might have a hidden quasar based on the discovery of a reddened source coinciding with its nucleus.[12]
References
[edit]- ^ a b c d e f g h "NED search results for PKS 0634-20". NASA/IPAC Extragalactic Database. Retrieved 2025-06-07.
- ^ a b Drake, Catherine L.; McGregor, Peter J.; Dopita, Michael A.; van Breugel, W. J. M. (November 2003). "Radio-Excess IRAS Galaxies: PMN/FSC Sample Selection". The Astronomical Journal. 126 (5): 2237–2267. arXiv:astro-ph/0306573. Bibcode:2003AJ....126.2237D. doi:10.1086/378714. ISSN 0004-6256.
- ^ Bolton, J. G.; Gardner, F. F.; Mackey, M. B. (September 1964). "The Parkes catalogue of radio sources, declination zone -20° to -60°". Australian Journal of Physics. 17 (3): 340. Bibcode:1964AuJPh..17..340B. doi:10.1071/PH640340. ISSN 0004-9506.
- ^ Bassani, L; Ursini, F; Malizia, A; Bruni, G; Panessa, F; Masetti, N; Saviane, I; Monaco, L; Venturi, T; Dallacasa, D; Bazzano, A; Ubertini, P (2021-01-21). "Soft gamma-ray selected giant radio galaxies: an update". Monthly Notices of the Royal Astronomical Society. 500 (3): 3111–3122. arXiv:2010.06427. doi:10.1093/mnras/staa3212. ISSN 0035-8711.
- ^ Danziger, I. J.; Goss, W. M.; Frater, R. H. (August 1978). "The giant radio galaxies PKS 0211-47 and PKS 0634-20". Monthly Notices of the Royal Astronomical Society. 184 (2): 341–349. Bibcode:1978MNRAS.184..341D. doi:10.1093/mnras/184.2.341. ISSN 0035-8711.
- ^ Strom, R. G.; Hamaker, J. P.; Willis, A. G. (1975), "Westerbork Observations of Large Radio Galaxies", Stars and Galaxies from Observational Points of View / Звезды И Галактики В Наблюдательном Аспекте, Dordrecht: Springer Netherlands, pp. 300–305, Bibcode:1976sgov.meet..300S, ISBN 978-94-017-5308-1, retrieved 2025-06-07
- ^ Kronberg, P. P.; Wielebinski, R.; Graham, D. A. (November 1986). "VLA and 100-m telescope observations of two giant galaxies : 0634-20 and 3C 445 (2221-02)". Astronomy and Astrophysics. 169: 63–70. Bibcode:1986A&A...169...63K. ISSN 0004-6361.
- ^ O'Sullivan, S P; Lenc, E; Anderson, C S; Gaensler, B M; Murphy, T (2018-01-20). "Faraday rotation at low frequencies: magnetoionic material of the large FRII radio galaxy PKS J0636−2036". Monthly Notices of the Royal Astronomical Society. 475 (3): 4263–4277. arXiv:1801.02452. doi:10.1093/mnras/sty171. ISSN 0035-8711.
- ^ Govoni, F.; Falomo, R.; Fasano, G.; Scarpa, R. (May 2000). "Optical surface photometry of radio galaxies. II. Observations and data analysis". Astronomy and Astrophysics Supplement Series. 143 (3): 369–390. arXiv:astro-ph/0001449. Bibcode:2000A&AS..143..369G. doi:10.1051/aas:2000338. ISSN 0365-0138.
- ^ a b Fosbury, R. a. E.; Tadhunter, C. N.; Bland, J.; Danziger, I. J. (June 1984). "Very extended ionized gas in radio galaxies - III. emission along the radio axis of PKS 0634-20". Monthly Notices of the Royal Astronomical Society. 208: 955–959. doi:10.1093/mnras/208.4.955. ISSN 0035-8711.
- ^ O'Dea, Christopher P.; Baum, Stefi A.; Maloney, Philip R.; Tacconi, Linda J.; Sparks, William B. (February 1994). "Constraints on Molecular Gas in Cooling Flows and Powerful Radio Galaxies". The Astrophysical Journal. 422: 467. Bibcode:1994ApJ...422..467O. doi:10.1086/173742. ISSN 0004-637X.
- ^ Simpson, Chris; Ward, M. J.; Wilson, A. S. (December 1995). "Evidence for an Obscured Quasar in the Giant Radio Galaxy PKS 0634-205". The Astrophysical Journal. 454: 683. Bibcode:1995ApJ...454..683S. doi:10.1086/176521. ISSN 0004-637X.
External links
[edit]- PKS 0634-20 on SIMBAD
- PKS 0634-20 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
