| PKS 0208-512 | |
|---|---|
 The blazar PKS 0208-512 | |
| Observation data (J2000.0 epoch) | |
| Constellation | Eridanus |
| Right ascension | 02 10 46.200 |
| Declination | −51° 01′ 01.892″ |
| Redshift | 0.999000 |
| Heliocentric radial velocity | 299,493 km/s |
| Distance | 7.926 Gly |
| Apparent magnitude (V) | 16.93 |
| Apparent magnitude (B) | 17.1 |
| Characteristics | |
| Type | HPQ, BL LAC |
| Other designations | |
| LEDA 2822981, HE 0208-5115, PMN J0210-5101, WMAP 158, 3FGL J0210.7-5101 | |
PKS 0208-512 is a blazar located in the southern constellation of Eridanus. It has a redshift of 1.003 and was first discovered in 1975 by astronomers conducting the Parkes 2700 MHz survey in Australia as a bright astronomical radio source. This object is also classified highly polarized with the radio spectrum appearing to be flat, thus making it a flat-spectrum radio quasar.
Description
PKS 0208-512 is found to be strongly variable on the electromagnetic spectrum. It shows a significant correlation between its intensity and spectral index, and is a source of gamma ray activity. It is known to have three powerful outbursts when observed at optical to near-infrared wavelengths. Between September 11 and 30 in 2008, the quasar brightened upon showing a flare, with increased magnitudes in both B-band and R-band. In the gamma ray lightcurve, it showed a variable flux reaching a factor of 6 on timescales of weeks.
A major gamma ray flare was detected in PKS 0208-512 between November 2019 and May 2020. Fermi-LAT observations proposed that its daily average gamma ray flux at > 100 MeV amplified to 1.1 ± 0.2 x 10 ph cm s on November 29, 2019, and subsequently to 2.0 ± 0.3 x 10 ph cm s by March 15, 2020. During the activity, the gamma ray lightcurve exhibited multiple peaks indicating the presence of subflares.
PKS 0208-512 has a complex radio structure. It is made up of a compact radio core with a projected spectral flux density of 2.8 Jansky and a jet component located at a position angle of 234° from the core with an angular separation of 1.7 mas. Using 2.3 and 5.0 GHz results, the core has a spectral index of 0.15, as well as having an obtained brightness temperature of 1.9 x 10 K. There is also a long jet present at a position angle of -129°. This jet is found similar to the milliarcsecond-scale radio jet's position angle, suggesting it is straight from parsec to kiloparsec scales. When seen through the jet's structure, there are four knot regions which increases orderly from the nucleus.
The supermassive black hole in PKS 0208-512 is estimated to be 6 x 10 Mʘ based on an assumption of its isotopic Eddington-limited emission. A luminosity of Ld ≈ 8 x 10 erg s was estimated for its accretion disk.
References
- Chatterjee, Ritaban; Bailyn, C. D.; Bonning, E. W.; Buxton, M.; Coppi, P.; Isler, J.; Urry, C. M.; Fossati, G.; Maraschi, L. (2011-08-01). "Optical-IR Re-Brightening of the Blazar PKS 0208-512". The Astronomer's Telegram. 3591: 1. Bibcode:2011ATel.3591....1C.
- ^ Stacy, J. Gregory; Vestrand, W. Thomas; Sreekumar, P. (2003-11-20). "The Gamma-Ray Blazar PKS 0208−512 from MeV to GeV Energies". The Astrophysical Journal. 598 (1): 216–231. doi:10.1086/377632. ISSN 0004-637X.
- Wall, J. V.; Shimmins, A. J.; Bolton, J. G. (1975-01-01). "The Parkes 2700 MHz Survey (Ninth Part): Supplementary Catalogue for the Declination zone -45o to -65o". Australian Journal of Physics Astrophysical Supplement. 34: 55.
- ^ Zhen, Z.Q.; Wan, T.S.; Moran, J.M.; Jauncey, D.L.; Jiang, D.R.; Edwards, P.G.; Costa, M.E. (April 1998). "A 5 GHz Southern Hemisphere VLBI Survey of Compact Radio Sources. II". The Astronomical Journal. doi:10.1086/300284. Retrieved 2024-10-26.
- Szostek, A. (2011-05-01). "Fermi LAT detection of gamma ray activity from blazar PKS 0208-512". The Astronomer's Telegram. 3338: 1. Bibcode:2011ATel.3338....1S.
- Lucarelli, F.; Tavani, M.; Pittori, C.; Verrecchia, F.; Bulgarelli, A.; Parmiggiani, N.; Fioretti, V.; Cardillo, M.; Casentini, C.; Piano, G.; Ursi, A.; Donnarumma, I.; Vercellone, S.; Gianotti, F.; Trifoglio, M. (2019-12-01). "AGILE detection of enhanced gamma-ray activity from the FSRQ PKS 0208-512". The Astronomer's Telegram. 13352: 1. Bibcode:2019ATel13352....1L.
- Nesci, R.; Kadler, M.; Ojha, R.; Pursimo, T.; Tosti, G.; Blanchard, J.; Lovell, J. (2011-06-01). "NIR follow-up of PKS 0208-512". The Astronomer's Telegram. 3421: 1. Bibcode:2011ATel.3421....1N.
- 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. (1993-03-01). "Detection of gamma-ray emission from the quasar PKS 0208-512". Astrophysical Journal, Part 2 - Letters. 405 (1): L21. doi:10.1086/186756. ISSN 0004-637X.
- ^ Chatterjee, Ritaban; Nalewajko, Krzysztof; Myers, Adam D. (2013-06-21). "Implications of the Anomalous Outburst in the Blazar PKS 0208–512". The Astrophysical Journal. 771 (2): L25. arXiv:1306.1531. doi:10.1088/2041-8205/771/2/l25. ISSN 2041-8205.
- Buxton, M.; Bailyn, C.; Coppi, P.; Kaptur, A.; Isler, J.; Urry, M.; Maraschi, L.; Fossati, G. (2008-10-01). "Increase in optical brightness of blazar PKS 0208-512". The Astronomer's Telegram. 1751: 1. Bibcode:2008ATel.1751....1B.
- Zhang, S.; Collmar, W.; Torres, D. F.; Wang, J.-M.; Lang, M.; Zhang, S.-N. (May 2010). "INTEGRAL and Swift/XRT observations of the source PKS 0208-512" (PDF). Astronomy and Astrophysics. 514: A69. doi:10.1051/0004-6361/200913655. ISSN 0004-6361.
- Ammenadka, Krishna Mohana; Bhattacharya, Debbijoy; Bhattacharyya, Subir; Bhatt, Nilay; Stalin, Chelliah Subramonian (2022-10-01). "Long-Term Monitoring of Blazar PKS 0208-512: A Change of γ-Ray Baseline Activity from EGRET to Fermi Era". Universe. 8 (10): 534. Bibcode:2022Univ....8..534A. doi:10.3390/universe8100534.
- ^ Khatoon, Rukaiya; Prince, Raj; Shah, Zahir; Sahayanathan, Sunder; Gogoi, Rupjyoti (2022-04-25). "Temporal and spectral study of PKS 0208−512 during the 2019–2020 flare". Monthly Notices of the Royal Astronomical Society. 513 (1): 611–623. arXiv:2104.12130. doi:10.1093/mnras/stac892. ISSN 0035-8711.
- ^ Perlman, Eric S.; Georganopoulos, Markos; Marshall, Herman L.; Schwartz, Daniel A.; Padgett, C. A.; Gelbord, Jonathan; Lovell, J. E. J.; Worrall, Diana M.; Birkinshaw, Mark; Murphy, David W.; Jauncey, David L. (2011-09-07). "Deep Multiwaveband Observations of the Jets of 0208-512 and 1202-262". The Astrophysical Journal. 739 (2): 65. arXiv:1107.2058. doi:10.1088/0004-637x/739/2/65. ISSN 0004-637X.
- 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. doi:10.1086/425578. ISSN 0067-0049.
