PKS 2131-021

PKS 2131-021
PKS 2131-021 as seen with DESI Legacy Surveys
Observation data (J2000.0 epoch)
Constellation	Aquarius
Right ascension	21^h 34^m 10.31^s
Declination	−01° 53′ 17.24″
Redshift	1.285[1]
Heliocentric radial velocity	385,233 km/s[1]
Apparent magnitude (V)	18.67[1]
Characteristics
Type	FRSQ;BLLAC, HPQ[1]
Other designations
4C -02.81, MRC 2131-021, PGC 2818139, OX -053, IRCF J213410.3-015317, 2FGL J2133.8-0154

PKS 2131-021 is a quasar and a BL Lacerate object,[2] producing an astrophysical jet.[3] lt is located in the constellation Aquarius and classified as a blazar, a type of active galactic nucleus whose relativistic jet points in the direction towards Earth.

Redshift estimation for PKS 2131-021

The redshift of PKS 2131-021 is 1.285, estimating the quasar to be located about 8.5 billion light-years away.[1] For more consistency according to researchers, they applied a cosmological parameters of H0 = 71 km s−1 Mpc−1, Ωm = 0.27, ΩΛ = 0.73.[4] On this model, the comoving coordinate distance of PKS 2131−021 is 3.97 Gpc, with an angular diameter distance of 1.74 Gpc, and luminosity distance of 9.08 Gpc.[5]

Black hole observation

Observations of its radio emission spanning a 45-year duration show epochs of periodic brightness variations. These nearly sinusoidal brightness changes have been interpreted as evidence of orbital motion of a binary black hole.[5] The orbital separation of the two black holes is inferred to be 200 to 2000 AU.[6][7] The periodic variability in the light curve indicates that the pair orbit each other about every two years, at a distance so close that they will merge in about 10,000 years (as viewed from the Earth).[8]

See also

• Supermassive black hole
• NGC 7727
• OJ 287

References

1. "Your NED Search Results". ned.ipac.caltech.edu. Retrieved 2024-05-24.
2. Sbarufatti, B.; Treves, A.; Falomo, R.; Heidt, J.; Kotilainen, J.; Scarpa, R. (2006-07-01). "ESO Very Large Telescope Optical Spectroscopy of BL Lacertae Objects. II. New Redshifts, Featureless Objects, and Classification Assessments". The Astronomical Journal. 132 (1): 1–19. arXiv:astro-ph/0601506. Bibcode:2006AJ....132....1S. doi:10.1086/503031. ISSN 0004-6256.
3. Liu, F. K.; Zhang, Y. H. (2002-01-01). "A new list of extra-galactic radio jets". Astronomy and Astrophysics. 381 (3): 757–760. arXiv:astro-ph/0212477. Bibcode:2002A&A...381..757L. doi:10.1051/0004-6361:20011572. ISSN 0004-6361.
4. Komatsu, E.; Dunkley, J.; Nolta, M. R.; Bennett, C. L.; Gold, B.; Hinshaw, G.; Jarosik, N.; Larson, D.; Limon, M.; Page, L.; Spergel, D. N.; Halpern, M.; Hill, R. S.; Kogut, A.; Meyer, S. S. (2009-02-01). "Five-Year Wilkinson Microwave Anisotropy Probe Observations: Cosmological Interpretation". The Astrophysical Journal Supplement Series. 180 (2): 330–376. arXiv:0803.0547. Bibcode:2009ApJS..180..330K. doi:10.1088/0067-0049/180/2/330. ISSN 0067-0049.
5. O'Neill, S.; et al. (2022). "The Unanticipated Phenomenology of the Blazar PKS 2131–021: A Unique Supermassive Black Hole Binary Candidate". The Astrophysical Journal Letters. 926 (2): 2. arXiv:2111.02436. Bibcode:2022ApJ...926L..35O. doi:10.3847/2041-8213/ac504b. S2CID 242757503.
6. DiCenza, Shawn (2022-03-24). "Astronomers Discover two Supermassive Black Holes Orbiting Each Other, Doomed to Collide in the Future". Universe Today. Retrieved 2022-03-29.
7. "These Two Black Hole Behemoths Will Merge in 10,000 Years". Sky & Telescope. 2022-02-28. Retrieved 2022-03-29.
8. "Colossal Black Holes Locked in Dance at Heart of Galaxy". California Institute of Technology. 2022-02-23. Retrieved 2022-03-29.