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PKS 1127-145
The quasar, PKS 1127-145.
Observation data (J2000.0 epoch)
Constellation	Crater
Right ascension	11 30 07.0526
Declination	−14° 49′ 27.388″
Redshift	1.180000
Heliocentric radial velocity	353,755 km/s
Distance	8.170 Gly
Apparent magnitude (V)	17.17
Apparent magnitude (B)	16.90
Characteristics
Type	Blazar, LPQ, FSRQ
Notable features	Longest 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 located in the constellation of Crater. This is a Gigahertz Peaked Spectrum object with a redshift of (z) 1.187, first discovered by astronomers in 1966. Its radio spectrum appears to be flat making it a flat-spectrum radio quasar, or an FRSQ in short.

Description

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

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 10 Kelvin. No extension is found in northwest direction. There is a presence of a compact core displaying strong increase of flux density with the outermost component being separated into several smaller regions enveloped completely by emission. A stationary feature is also seen located 4 mas from the core via a 22 GHz image taken by VLBI. Circular polarization has also been found in the quasar as well.

X-ray jet

An X-ray jet has been discovered in PKS 1127-145 by Chandra X-ray Observatory. With an estimated length of 300 kiloparsecs, this makes the longest one detected so far in any of the high redshift quasars. 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.

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.

References

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. Bibcode:2003ASPC..290..361S.
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. Bibcode:2001AJ....121.1306T. 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 Infrared Photons on Parsec Scales", The Astrophysical Journal, 600: L27 – L30, arXiv:astro-ph/0311411, doi:10.1086/381497
5. Bolton, J. G.; Kinman, T. D. (September 1966). "Radio and Optical Data on Twelve Quasi-Stellar Objects". The Astrophysical Journal. 145: 951. Bibcode:1966ApJ...145..951B. 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. Bibcode:2020ATel14280....1D.
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. Bibcode:2022ATel15397....1D.
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. Bibcode:2022ATel15379....1R.
9. ^ 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. arXiv:2405.04935. Bibcode:2024A&A...687A.287O. 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. Bibcode:2022ATel15385....1D.
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. Bibcode:2022ATel15731....1B.
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 (4): 1357–1370. arXiv:astro-ph/9803104. Bibcode:1998AJ....115.1357S. doi:10.1086/300284.
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. Bibcode:1996A&A...308..415B.
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. 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. Bibcode:1971NPhS..231...93S. 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. arXiv:astro-ph/0201116. Bibcode:2002ApJ...570..543S. 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. arXiv:astro-ph/0611406. Bibcode:2007ApJ...657..145S. doi:10.1086/510898. ISSN 0004-637X.

External links

• PKS 1127-145
• PKS 1127-145 on NASA/IPAC Database

v t e Constellation of Crater
List of stars in Crater Crater in Chinese astronomy
Stars	Bayer α (Alkes) β γ δ ε ζ η θ ι κ λ ψ Variable R SZ TV HR 4305 4428 HD 96167 98219 (Hunahpú) 98649 Other BD−10°3166 DENIS-P J1058.7−1548 LP 791-18 WASP-34 (Amansinaya) WD 1054–226
Exoplanets BD-10°3166 b HD 96167 b WASP-31b
Galaxies	NGC 3511 3597 3974 3981 Other Crater 2 1ES 1101-232 LEDA 1000714 PKS 1127-145 RX J1131-1231
Galaxy clusters Abell 1146 NGC 4038 Group
Astronomical events GRB 011211
Category

• Quasars
• Crater (constellation)
• LEDA objects
• Active galaxies
• Blazars
• Astronomical objects discovered in 1966