Langbahn Team – Weltmeisterschaft

PKS 0454-234

PKS 0454-234
The blazar PKS 0454-234.
Observation data (J2000.0 epoch)
ConstellationLepus
Right ascension04h 57m 03.179s
Declination−23° 24′ 52.020″
Redshift1.003000
Heliocentric radial velocity300,692 km/s
Distance7.531 Gly
Apparent magnitude (V)18.5
Apparent magnitude (B)18.85
Characteristics
TypeHPQ, Blazar, BL Lac
Other designations
OHIO F -292, 4FGL J0457.0-2324, WMAP 128, QSO B0454-234, PKS J0457-2324, NVSS J045703-232452

PKS 0454-234 is a blazar[1] located in the constellation of Lepus. It is classified as a highly polarized quasar[2][3] with a redshift of (z) 1.003.[4] This object was first discovered in 1970 during a 1415 MHz continuum survey conducted by Ohio State University where it was given the designation, OF -292.[5] The radio spectrum of this source is flat, making it a flat-spectrum radio quasar.[4][6][7]

Description

PKS 0454-234 is found variable on the electromagnetic spectrum. It is known to show powerful outbursts with a spectrum showing as inverted right up to 20 GHz, but becomes steeper upon reaching its quiescence state after 8 GHz.[2] In additional, PKS 0454-234 exhibits extreme gamma ray activity observed by Large Area Telescope in January 2009[8] and by the AGILE satellite, where the activity reached above 100 MeV in August 2019.[9] Flares were detected in near-infrared wavelengths in 2011 and 2013.[10][11] An observation conducted by Japanese scientists in 2013, also found PKS 0454-234 has a soft spectrum with an estimated integral flux of 2.82 x 10-7 ± 1.10 x 10-9 in the ranges of 0.1-300 GeV.[12]

Very Long Baseline Interferometry radio imaging taken at 5 GHz showed PKS 0454-234 having an asymmetric morphology, consisting of a strong radio core and compact jetlike component that is located in a northwest direction with a position angle of -62°. This core has a brightness temperature of around 6 x 1011 Kelvin.[13] When imaged at 2.3 and 8.5 GHz, it shows the object mainly having a core-dominated structure and a weak jet extending out by 5 mas along the position angle of -130°.[14] There is also a presence of a secondary structure located at a distance of 1 mas southeast with its secondary components having 90° position angle differences according to multiepoch monitoring done by United States Naval Observatory (USNO).[15]

In 2022, PKS 0454-234 was found to show two quasi-periodic oscillation signals with duration periods of 3.51 ± 0.33 and 6.10 ± 0.82 years. This might be explained by a binary black hole model with estimated mass of 4.69 x 108 Mʘ and a gravitational wave emission having a decay time period of 9.56 x 104 years.[16]

References

  1. ^ Gaylard, Michael; West, Marion; Edwards, Philip; Stevens, Jamie; Ojha, Roopesh; Hungwe, Faith (2011-10-01). "Elevated fluxes at multiple radio frequencies seen in flaring blazar PKS 0454-234". The Astronomer's Telegram. 3713: 1. Bibcode:2011ATel.3713....1G.
  2. ^ a b Tornikoski, M.; Jussila, I.; Johansson, P.; Lainela, M.; Valtaoja, E. (March 2001). "Radio Spectra and Variability of Gigahertz-Peaked Spectrum Radio Sources and Candidates". The Astronomical Journal. 121 (3): 1306–1318. Bibcode:2001AJ....121.1306T. doi:10.1086/319417. ISSN 0004-6256.
  3. ^ Thompson, D. J.; Bertsch, D. L.; Dingus, B. L.; Fichtel, C. E.; Hartman, R. C.; Hunter, S. D.; Kanbach, G.; Kniffen, D. A.; Lin, Y. C.; Mattox, J. R.; Mayer-Hasselwander, H. A.; Michelson, P. F.; von Montigny, C.; Nolan, P. L.; Schneid, E. J. (1993-09-01). "EGRET Observations of Active Galactic Nuclei: 0836+710, 0454-234, 0804+499, 0906+430, 1510-089, and 2356+196". The Astrophysical Journal. 415: L13. Bibcode:1993ApJ...415L..13T. doi:10.1086/187021. ISSN 0004-637X.
  4. ^ a b Armstrong, Thomas; Brown, Anthony M.; Chadwick, Paula M. (2017-05-29). "Fermi-LAT high-z active galactic nuclei and the extragalactic background light". Monthly Notices of the Royal Astronomical Society. 470 (4): 4089–4098. arXiv:1705.11185. doi:10.1093/mnras/stx1309. ISSN 0035-8711.
  5. ^ Fitch, L. T.; Dixon, R. S.; Kraus, J. D. (June 1969). "A High-Sensivity 1415-MHz Survey between Declinations 0 and +20 degrees (OHIO part III)". The Astronomical Journal. 74: 612. doi:10.1086/110844. ISSN 0004-6256.
  6. ^ Torniainen, I.; Tornikoski, M.; Teräsranta, H.; Aller, M. F.; Aller, H. D. (2005-05-13). "Long term variability of gigahertz-peaked spectrum sources and candidates" (PDF). Astronomy & Astrophysics. 435 (3): 839–856. Bibcode:2005A&A...435..839T. doi:10.1051/0004-6361:20041886. ISSN 0004-6361.
  7. ^ Hungwe, F.; Dutka, M.; Ojha, R.; Escande, L.; Schinzel, F. K. (2011-10-01). "Sustained and increasing gamma-ray activity of the blazar PKS 0454-234". The Astronomer's Telegram. 3703: 1. Bibcode:2011ATel.3703....1H.
  8. ^ Cavazzuti, E.; Hays, E. (2009-01-01). "Fermi LAT detection of increasing gamma-ray activity of blazar PKS 0454-234". The Astronomer's Telegram. 1898: 1. Bibcode:2009ATel.1898....1C.
  9. ^ Cardillo, M.; Verrecchia, F.; Bulgarelli, A.; Parmiggiani, N.; Fioretti, V.; Tavani, M.; Casentini, C.; Piano, G.; Ursi, A.; Lucarelli, F.; Donnarumma, C. Pittori I.; Vercellone, S.; Gianotti, F.; Trifoglio, M.; Giuliani, A. (2019-08-01). "AGILE detection of gamma-ray flaring activity from the FSRQ PKS 0454-234". The Astronomer's Telegram. 13011: 1. Bibcode:2019ATel13011....1C.
  10. ^ Nesci, R. (2011-10-01). "NIR follow-up of PKS 0454-234". The Astronomer's Telegram. 3722: 1. Bibcode:2011ATel.3722....1N.
  11. ^ Carrasco, L.; Recillas, E.; Porras, A.; Chabushyan, V.; Carraminana, A. (2013-11-01). "Another NIR Flare of PKS0454-234". The Astronomer's Telegram. 5583: 1. Bibcode:2013ATel.5583....1C.
  12. ^ Tsujimoto, Shimpei; Kushida, Junko; Nishijima, Kyoshi; Kodani, Kazuhito (2014-03-19). "The Possibility for the Detection of the Sub-TeV Gamma-Ray Emission from Fermi Blazars". Proceedings of the 12th Asia Pacific Physics Conference (APPC12). Journal of the Physical Society of Japan. doi:10.7566/jpscp.1.013106. ISBN 978-4-89027-101-6.
  13. ^ Shen, Z.-Q.; Wan, T.-S.; Moran, J. M.; Jauncey, D. L.; Reynolds, J. E.; Tzioumis, A. K.; Gough, R. G.; Ferris, R. H.; Sinclair, M. W.; Jiang, D.-R.; Hong, X.-Y.; Liang, S.-G.; Edwards, P. G.; Costa, M. E.; Tingay, S. J. (1998-04-01). "A 5 GHz Southern Hemisphere VLBI Survey of CompactRadio Sources. II". The Astronomical Journal. 115 (4): 1357. arXiv:astro-ph/9803104. Bibcode:1998AJ....115.1357S. doi:10.1086/300284. ISSN 1538-3881.
  14. ^ Jorstad, Svetlana G.; Marscher, Alan P.; Mattox, John R.; Wehrle, Ann E.; Bloom, Steven D.; Yurchenko, Alexei V. (June 2001). "Multiepoch Very Long Baseline Array Observations of EGRET-detected Quasars and BL Lacertae Objects: Superluminal Motion of Gamma-Ray Bright Blazars". The Astrophysical Journal Supplement Series. 134 (2): 181–240. arXiv:astro-ph/0101570. Bibcode:2001ApJS..134..181J. doi:10.1086/320858. ISSN 0067-0049.
  15. ^ Fomalont, E. B.; Frey, S.; Paragi, Z.; Gurvits, L. I.; Scott, W. K.; Taylor, A. R.; Edwards, P. G.; Hirabayashi, H. (November 2000). "The VSOP 5 GHz Continuum Survey: The Prelaunch VLBA Observations". The Astrophysical Journal Supplement Series. 131 (1): 95–183. Bibcode:2000ApJS..131...95F. doi:10.1086/317368. ISSN 0067-0049.
  16. ^ Abdou, Yasser; Hashad, Mohamed; Boundok, Ibrahim; El-Zant, Amr (2022-11-21). "Possible Quasi-periodic Oscillation in the Distant γ-Ray Blazar PKS 0454–234". Arab Journal of Nuclear Sciences and Applications: 0. doi:10.21608/ajnsa.2022.158331.1629. ISSN 2090-4258.
Quelle: https://en.wikipedia.org/wiki/PKS_0454-234