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PKS 2052-474

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PKS 2052-474
DSS image of PKS 2052-474.
Observation data (J2000.0 epoch)
ConstellationIndus
Right ascension20h 56m 16.35s
Declination−47° 14′ 47.62″
Redshift1.491500
Heliocentric radial velocity447,140 km/s
Distance9.335 Gly
Apparent magnitude (V)19.1
Apparent magnitude (B)18.29
Characteristics
TypeFSRQ; LPQ blazar
Other designations
PKS 2052-47, 2MASS J20561636-4714475, PMN J2056-4714, SUMSS J205616-471448, LEDA 2830665, Cul 2052-474, WMAP 208, G4Jy 1665, RX J2056.2-4714

PKS 2052-474 is a blazar[1] located in the southern constellation of Indus. The redshift of the object is (z) 1.491[2] and was discovered as a radio source during observations conducted at Parkes Observatory located in New South Wales, on September 1964.[3] It was later identified as a galaxy by Keith Tritton,[4] with its radio spectrum described as flat, thus making it a flat-spectrum source.[5][6]

Description

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PKS 2052-474 is very variable on the electromagnetic spectrum. It is noted for its increasing gamma-ray activity as indicated on 9 August 2009, where it reach a high state with a gamma-ray flux measurement of 8.7 ± 1.6 x 10-7 photons cm-2 s-1, detected by Fermi Gamma-ray space Telescope, which was more than a factor of 4.[1] It also underwent two minor flares between June and July 2009, with its flux increasing upwards to 15.6 magnitude in R-bands by 21 July, followed by an outburst in August.[7][8] On 2 March 2020, it was found in an elevated gamma-ray emission state with its flux measured as 1.2 ± -0.2 x 10-6 photons cm-2 s-1 making this the highest daily flux detected in this source.[9] Data from a light curve, have showed PKS 2052-474 has two flaring periods, occurring in February and June 2009, but absence of significant emission line variability.[10][11][12]

The source of PKS 2052-474 is compact. Very Long Baseline Interferometry imaging at 8.4 GHz, have shown the object has a prominent radio core measuring 0.38 Jansky and a jet component located at a distance of 0.7 milliarcseconds with a position angle of -66°.[13][14] At 4.8 GHz, imaging showed the source has the same core with the weakest feature interpreted as a secondary component appearing 8 milliarcseconds to the east, likely interpreted as an imaging artifact.[14] A two-sided jet is seen emerging from the core region on arcsecond scales while first-epoch imaging results showed there is a weak jet towards west direction.[15][16]

PKS 2052-474 has been used as a Molonglo calibrator. When observed by the Molonglo Observatory Synthesis Telescope, the source is found to have a steep radio spectrum at a low frequency. However, it then flattens when reaching high frequencies prompting astronomers to classify it as variable on a time scale amongst 17 other sources. This is suggested by scintillation in interstellar medium rather caused by intrinsic effects on the source.[17] A lower limit has also been calculated for the object with a brightness temperature of 2 x 1011 K, based on an upper limit of the source's angular size.[11] There is evidence PKS 2052-474 has quasi-periodic periodicity of 637 days, making it a candidate quasar with a binary supermassive black hole.[18][19] An accretion disk temperature of 1.23 (± 0.33) x 104 K and disk luminosity of 1.29 (± 1.68) x 1046 erg s-1 has been calculated for PKS 2052-474.[20]

References

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  1. ^ a b "Fermi LAT detection of increasing gamma-ray activity of blazar PKS 2052-474". The Astronomer's Telegram. Retrieved 2025-07-06.
  2. ^ "NED search results for PKS 2052-474". NASA/IPAC Extragalactic Database. Retrieved 2025-07-06.
  3. ^ 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.
  4. ^ Tritton, K. P.; Whitworth, D. P. D. (1973-12-01). "Identifications of Southern Parkes Radio sources". Monthly Notices of the Royal Astronomical Society. 165 (3): 253–257. Bibcode:1973MNRAS.165..253T. doi:10.1093/mnras/165.3.253. ISSN 0035-8711.
  5. ^ Chang, C. S.; Ros, E.; Kadler, M.; Ojha, R.; Collaboration, the Fermi Lat; Team, the Tanami; Team, the F.-Gamma (2010-01-10), Multiwavelength campaign of the gamma-ray flaring source PKS 2052-47, arXiv:1001.1563
  6. ^ Chang, Chin-Shin (October 2010). "Active Galactic Nuclei throughout the Spectrum: M 87, PKS 2052-47, and the MOJAVE sample". Ph.D. Thesis. Bibcode:2010PhDT........66C.
  7. ^ Hauser, M.; Behera, B.; Hagen, H.; Wagner, S. (August 2009). "Detection of an optical flare from PKS 2052-474". The Astronomer's Telegram. 2158: 1. Bibcode:2009ATel.2158....1H.
  8. ^ Bailyn, C.; Muir, G. (August 2009). "Continued Optical Activity in PKS 2052-474". The Astronomer's Telegram. 2162: 1. Bibcode:2009ATel.2162....1B.
  9. ^ Buson, S.; Angioni, R. (March 2020). "Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ PKS 2052-47". The Astronomer's Telegram. 13541: 1. Bibcode:2020ATel13541....1B.
  10. ^ Abdo, A. A.; Ackermann, M.; Ajello, M. (October 2010). "Gamma-ray Light Curves and Variability of Bright Fermi-detected Blazars". The Astrophysical Journal. 722 (1): 520–542. arXiv:1004.0348. Bibcode:2010ApJ...722..520A. doi:10.1088/0004-637X/722/1/520.
  11. ^ a b Blanchard, J. M.; Lovell, J. E. J.; Ojha, R.; Kadler, M.; Dickey, J. M.; Edwards, P. G. (2012-02-01). "High resolution rapid response observations of compact radio sources with the Ceduna Hobart Interferometer (CHI)" (PDF). Astronomy & Astrophysics. 538: A150. arXiv:1201.5159. Bibcode:2012A&A...538A.150B. doi:10.1051/0004-6361/201117593. ISSN 0004-6361.
  12. ^ Isler, Jedidah C.; Urry, C. M.; Bailyn, C.; Smith, P. S.; Coppi, P.; Brady, M.; MacPherson, E.; Hasan, I.; Buxton, M. (2015-04-23). "THE SMARTS MULTI-EPOCH OPTICAL SPECTROSCOPY ATLAS (SaMOSA): AN ANALYSIS OF EMISSION LINE VARIABILITY IN SOUTHERN HEMISPHERE FERMI BLAZARS". The Astrophysical Journal. 804 (1): 7. arXiv:1502.01018. Bibcode:2015ApJ...804....7I. doi:10.1088/0004-637x/804/1/7. ISSN 1538-4357.
  13. ^ Ojha, Roopesh; Fey, Alan L.; Johnston, Kenneth J.; Jauncey, David L.; Reynolds, John E.; Tzioumis, Anastasios K.; Quick, Jonathan F. H.; Nicolson, George D.; Ellingsen, Simon P.; Dodson, Richard G.; McCulloch, Peter M. (June 2004). "VLBI Observations of Southern Hemisphere ICRF Sources. I." The Astronomical Journal. 127 (6): 3609–3621. Bibcode:2004AJ....127.3609O. doi:10.1086/421001. ISSN 0004-6256.
  14. ^ a b Edwards, P. G.; Ojha, R.; Dodson, R.; Lovell, J. E. J.; Reynolds, J. E.; Tzioumis, A. K.; Quick, J.; Nicolson, G.; Tingay, S. J. (January 2018). "VLBI Observations of Southern Gamma-Ray Sources. III". Publications of the Astronomical Society of Australia. 35 e009. Bibcode:2018PASA...35....9E. doi:10.1017/pasa.2018.4. hdl:20.500.11937/67158. ISSN 1323-3580.
  15. ^ Marshall, H. L.; Schwartz, D. A.; Lovell, J. E. J.; Murphy, D. W.; Worrall, D. M.; Birkinshaw, M.; Gelbord, J. M.; Perlman, E. S.; Jauncey, D. L. (January 2005). "A Chandra Survey of Quasar Jets: First Results". The Astrophysical Journal Supplement Series. 156 (1): 13–33. arXiv:astro-ph/0409566. Bibcode:2005ApJS..156...13M. doi:10.1086/425578. ISSN 0067-0049.
  16. ^ Ojha, R.; Kadler, M.; Böck, M.; Booth, R.; Dutka, M. S.; Edwards, P. G.; Fey, A. L.; Fuhrmann, L.; Gaume, R. A.; Hase, H.; Horiuchi, S.; Jauncey, D. L.; Johnston, K. J.; Katz, U.; Lister, M. (2010-09-01). "TANAMI: tracking active galactic nuclei with austral milliarcsecond interferometry - I. First-epoch 8.4 GHz images" (PDF). Astronomy & Astrophysics. 519: A45. arXiv:1005.4432. Bibcode:2010A&A...519A..45O. doi:10.1051/0004-6361/200912724. ISSN 0004-6361.
  17. ^ Gaensler, B. M.; Hunstead, R. W. (April 2000). "Long-term Monitoring of Molonglo Calibrators". Publications of the Astronomical Society of Australia. 17 (1): 72–82. arXiv:astro-ph/9911194. Bibcode:2000PASA...17...72G. doi:10.1071/AS00072. ISSN 1323-3580.
  18. ^ Covino, S; Sandrinelli, A; Treves, A (2019-01-01). "Gamma-ray quasi-periodicities of blazars. A cautious approach". Monthly Notices of the Royal Astronomical Society. 482 (1): 1270–1274. arXiv:1810.02409. doi:10.1093/mnras/sty2720. ISSN 0035-8711.
  19. ^ A., Prokhorov, D.; A., Moraghan (November 2017). "A search for cyclical sources of γ-ray emission on the period range from days to years in the Fermi-LAT sky" (PDF). Monthly Notices of the Royal Astronomical Society. 471 (3). doi:10.1093/mnra (inactive 6 July 2025). ISSN 0035-8711. Archived from the original on 2022-08-09. Retrieved 2025-07-06.{{cite journal}}: CS1 maint: DOI inactive as of July 2025 (link) CS1 maint: multiple names: authors list (link)
  20. ^ Rajguru, Garima; Chatterjee, Ritaban (2024-11-22). "Accretion disc–jet decomposition from the optical-near infrared monitoring of Fermi blazars". Monthly Notices of the Royal Astronomical Society. 535 (4): 3595–3610. arXiv:2412.10343. doi:10.1093/mnras/stae2608. ISSN 0035-8711.
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