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PKS 1127-145

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PKS 1127-145
The quasar, PKS 1127-145.
Observation data (J2000.0 epoch)
ConstellationCrater
Right ascension11h 30m 07.0526s
Declination−14° 49′ 27.388″
Redshift1.180000
Heliocentric radial velocity353,755 km/s
Distance8.170 Gly
Apparent magnitude (V)17.17
Apparent magnitude (B)16.90
Characteristics
TypeBlazar, LPQ, FSRQ
Notable featuresLongest X-ray jet detected in a high redshift quasar
Other designations
INTREF 453, 2E 2471, LEDA 2826758, 4FGL J1129.8-1447, WMAP 157, QSO B1127-1432, PKS 1127-14, OHIO M -146, PMN J1130-1449

PKS 1127-145 is a radio-loud quasar[1] located in the constellation of Crater. This is a Gigahertz Peaked Spectrum object[2][3] with a redshift of (z) 1.187,[4] first discovered by astronomers in 1966.[5] Its radio spectrum appears to be flat making it a flat-spectrum radio quasar, or an FRSQ in short.[6][7]

Description

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PKS 1127-145 displays blazar-like behavior. It is known to undergo a period of gamma ray activity,[8] especially in December 2020 where its daily gamma ray flux reached a peak of (E > 100 MeV) of (1.6 ± 0.3) x 10-6 photons cm-2 s-1.[9] Two flares were detected by Fermi-LAT in May and October 2022.[10][11]

The radio structure of PKS 1127-145 is found complex. A radio image made by the Very Long Baseline Interferometry (VLBI) shows the object has two components, mainly a bright component and a much weaker component with same brightness temperatures of 1.3 x 1011 Kelvin. No extension is found in northwest direction.[12] There is a presence of a compact core displaying strong increase of flux density[13] with the outermost component being separated into several smaller regions enveloped completely by emission.[9] A stationary feature is also seen located 4 mas from the core via a 22 GHz image taken by VLBI.[14] Circular polarization has also been found in the quasar as well.[15]

X-ray jet

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Chandra image of the X-ray jet in PKS 1127-145.

An X-ray jet has been discovered in PKS 1127-145 by Chandra X-ray Observatory.[16] With an estimated length of 300 kiloparsecs, this makes the longest one detected so far in any of the high redshift quasars.[17] Advanced CCD Imaging Spectrometer also revealed a complex structure in the X-ray jet from the core with bright knots of different morphologies. Two of the knots showed changes in their profiles while the other knot is found fainter with presence of X-ray emission scattered over a large area.[18]

A more in-depth analysis of the X-ray jet in PKS 1127-145 showed the inner jet of PKS 1127-145 located from the core is found to be extremely polarized and a parallel magnetic field towards the jet's axis. Upon reaching 18 arcseconds from the core, the jet suddenly bends slightly causing the re-brightening of radio emission. In additional, there is a 90° rotation of the magnetic field suggesting it might be compressed to the plane that is found perpendicular to the axis.[9]

References

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  1. ^ Duffy, Ryan T.; Siemiginowska, A.; Kashyap, V.; Stein, N.; Migliori, G. (January 2014). Investigating the emission mechanisms of the jet in the quasar PKS 1127-145. American Astronomical Society Meeting #223. Vol. 223. p. 251.15. Bibcode:2014AAS...22325115D.
  2. ^ Siemiginowska, A.; Aldcroft, T. L.; Elvis, M.; Bechtold, J.; Brunetti, G.; Stanghellini, C. (2003-01-01). "First Chandra Images of GPS quasars". Astronomical Society of the Pacific, Conference Series. 290: 361.
  3. ^ 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. doi:10.1086/319417. ISSN 0004-6256.
  4. ^ Blazejowski, Michal; Siemiginowska, Aneta; Sikora, Marek; Moderski, Rafal; Bechtold, Jill (2003-11-17), X-Ray Emission from the Quasar PKS 1127-145: Comptonized IR Photons on Parsec Scales, doi:10.48550/arXiv.astro-ph/0311411, retrieved 2024-12-14
  5. ^ Bolton, J. G.; Kinman, T. D. (September 1966). "Radio and Optical Data on Twelve Quasi-Stellar Objects". The Astrophysical Journal. 145: 951. doi:10.1086/148842. ISSN 0004-637X.
  6. ^ D'Ammando, Filippo (2020-12-01). "Continued Swift observations of the flat spectrum radio quasar PKS 1127-14". The Astronomer's Telegram. 14280: 1.
  7. ^ D'Ammando, Filippo (2022-05-01). "Continued Swift observations of the FSRQ PKS 1127-14 during a high activity period". The Astronomer's Telegram. 15397: 1.
  8. ^ Rani, B.; Valverde, J.; La Mura, G. (2022-05-01). "Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ PKS 1127-14". The Astronomer's Telegram. 15379: 1.
  9. ^ a b c Orienti, M.; Siemiginowska, A.; D’Ammando, F.; Migliori, G. (July 2024). "A high-resolution radio morphology and polarization of the kiloparsec-scale X-ray jet of PKS 1127−145". Astronomy & Astrophysics. 687: A287. doi:10.1051/0004-6361/202449286. ISSN 0004-6361.
  10. ^ D'Ammando, Filippo (2022-05-01). "Swift follow-up of the flaring FSRQ PKS 1127-14". The Astronomer's Telegram. 15385: 1.
  11. ^ Britto, R. J.; Valverde, J.; La Mura, G. (2022-10-01). "Fermi-LAT detection of second record flare of FSRQ PKS 1127-14". The Astronomer's Telegram. 15731: 1.
  12. ^ 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. (April 1998). "A 5 GHz SOUTHERN HEMISPHERE VLBI SURVEY OF COMPACT RADIO SOURCES. II". The Astronomical Journal. 115: 1357–1370.
  13. ^ Bondi, M.; Padrielli, L.; Fanti, R.; Ficarra, A.; Gregorini, L.; Mantovani, F. (1996). "Three epoch VLBI observations at 18cm of low frequency variable sources". Astronomy & Astrophysics. 308: 415–427.
  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. doi:10.1086/320858. ISSN 0067-0049.
  15. ^ Seaquist, E. R. (May 1971). "Circular Polarization of the Radio Source PKS 1127—14 at 3,240 MHz". Nature Physical Science. 231 (22): 93–97. doi:10.1038/physci231093a0. ISSN 2058-1106.
  16. ^ "Chandra :: Photo Album :: PKS 1127-145 :: 06 Feb 02". chandra.harvard.edu. Retrieved 2024-12-14.
  17. ^ Siemiginowska, Aneta; Bechtold, Jill; Aldcroft, Thomas L.; Elvis, Martin; Harris, D. E.; Dobrzycki, Adam (2002-05-10). "Chandra Discovery of a 300 Kiloparsec X‐Ray Jet in the Gigahertz‐peaked Spectrum Quasar PKS 1127−145". The Astrophysical Journal. 570 (2): 543–556. doi:10.1086/339629. ISSN 0004-637X.
  18. ^ Siemiginowska, Aneta; Stawarz, Łukasz; Cheung, C. C.; Harris, D. E.; Sikora, Marek; Aldcroft, Thomas L.; Bechtold, Jill (March 2007). "The 300 kpc Long X‐Ray Jet in PKS 1127−145,z= 1.18 Quasar: Constraining X‐Ray Emission Models". The Astrophysical Journal. 657 (1): 145–158. doi:10.1086/510898. ISSN 0004-637X.
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