B2 1420+32

B2 1420+32
SDSS image of B2 1420+32 (located center)
Observation data (J2000.0 epoch)
ConstellationBoötes
Right ascension14h 22m 30.380s
Declination+32° 23′ 10.440″
Redshift0.682
Heliocentric radial velocity143,130 km/s
Distance6.3 billion light years
Apparent magnitude (V)19.16
Characteristics
TypeFSRQ
Other designations
FBQS J1422+3223, 6C 142016+323628, OHIO Q 334, QSO B1420+326, 7C 142021.30+323647.00, RX J1422.5+3223, NVSS J142230+322309, PGC 4066234

B2 1420+32 also known as OQ 334 and QSO B1420+326, is a flat-spectrum radio quasar[1] in the constellation of Boötes. Its redshift is estimated as (z) 0.682 corresponding to a light travel time of 6.3 billion light years[2] and was first detected in March 1973 as a blue stellar object.[3] This object gained significant attention because of its renewed flaring activity, categorized as changing looking blazar and is the fourth known distant object displaying very high energy radio emission.

Description

B2 1420+32 is extremely variable on an electromagnetic spectrum. A known blazar, it is shown to undergo extreme gamma-ray activity in 2018 after a ten-year quiescent period, displaying a three day flux of 4.79 ± 0.59 averaging a photon index of 1.96 ± 0.10.[4] The same year in December, it reached a daily average gamma-ray flux of 1.3 ± 0.2 x 10-6 photons cm-2 s-1, making it 180 times greater than its observed flux in the four year observation period.[5] On December 30 and 31 in 2019, the fluxes were estimated to be 0.9 ± 0.1 x 10-6 photons cm-2 s-1 and 1.7 ± 0.2 x 10-6 photons cm-2 s-1.[6] Two near-infrared flares were observed from the object displaying a K-band flux of 14.28 ± 0.05 on June 27, 2019, and H-band flux of 12.14 ± 0.03 on March 31, 2023.[7][8]

During the first month of 2020, B2 1420+32 underwent a high energy powerful gamma-ray flare,[9][10][11] with its radio emission noted as increasing by February.[12] In July 2021, it again underwent a flaring period, detected by astronomers at 14 and 7 milliammeter bands, who happened to observe it as part of the TELAMON program.[13] Raj Prince noted one of the peaks during its flaring state display the highest known gamma-ray photon level at 77 GeV, indicating the emitting region is either situated on the broad-line region outer boundary or at the torus inner edge.[4] DCF analysis, would find the time lags of its light curve is 1.69 days.[14]

Additionally to its extreme gamma-ray activity, B2 1420+32 has optical variability.[15] As detected on July 30 2021, astronomers from the Crimean Astrophysical Observatory noted its increasing activity with an R-band magnitude of 15.156; it previously had an R-band magnitude of 15.50 the previous night.[16] A year later on July 31, 2022, it reached 16.13.[17] The linear polarization levels also increased from 27.5% to 33.5% in 2021 but decreased to 22.5% in 2022.[16][17]

The nucleus of B2 1420+32 is constantly active due to a presence of its accretion disk around its supermassive black hole. The black hole in the center of the object, is estimated to be 4 × 108 Mʘ based on a virial-based scaling relationship with an accretion disk luminosity of 2 × 1018 erg s-1.[18][11]

The active galactic nucleus (AGN) of B2 1420+32 can be described as change looking, marked by a series of changes in spectral variability and broad emission lines. The object is categorized as a flat-spectrum (FSRQ) radio quasar, but flaring activity occurring in January 2018 lead the observers to reclassify it as a BL Lacertae object (BL Lac).[19][20] However 96 days later, it has since reverted to back to its original classification of an FSRQ, but since changed again to its BL Lac state after 416 days in July 2019 and so on.[21][22][23] This is suggested by changes in its accretion mode but was later revealed the jet of B2 1420+32 actually influenced the change in its continuum flux, thus the change of classification between FSRQ and BL Lac.[21][20]

Polarized intensity radio mapping by Very Long Baseline Array, have showed the source of B2 1420+32 is made up of a bright single radio core situated at the jet's northwestern end, with a weaker extended jet feature located at a position angle of 130°. There is a polarized feature interpreted as a jet knot shown separating from the core. Linear approximation has found the knot is moving at superluminal motion at speeds of 12.0 ± 1.7c and happens to be ejecting. The polarization direction close to the direction of the jet also suggested the knot might be interpreted as a moving shock.[11]

References

  1. ^ "Multi-band optical observations of the flaring blazar OQ 334 (B2 1420+326) with the new 50cm robotic telescope at IAO". The Astronomer's Telegram. Retrieved 2025-07-14.
  2. ^ Marchini, Alessandro; Bonnoli, Giacomo; Bellizzi, Lorenzo; Millucci, Vincenzo; Paoletti, Riccardo; Stiaccini, Leonardo; Truzzi, Stefano; Ventura, Sofia; Conti, Massimo; Vallerani, Claudio (July 2019). "The flaring blazar B2 1420+32 below R=14". The Astronomer's Telegram. 12914: 1. Bibcode:2019ATel12914....1M.
  3. ^ Bergamini, R.; Bracessi, A.; Colla, G.; Fanti, C.; Ficarra, A.; Formiggini, L.; Gandolfi, E.; Gioia, I.; Lari, C.; Marano, B.; Padrielli, L.; Tomasi, P.; Vigotti, M. (March 1973). "Optical Identifications of Ra- diosources from the B 2 Catalogue. Quasi Stellar Sources". Astronomy and Astrophysics. 23: 195. Bibcode:1973A&A....23..195B. ISSN 0004-6361.
  4. ^ a b Prince, Raj; Khatoon, Rukaiya; Stalin, C. S. (April 2021). "Broad-band study of OQ 334 during its flaring state". Monthly Notices of the Royal Astronomical Society. 502 (4): 5245–5258. arXiv:2102.03516. doi:10.1093/mnras/stab369. ISSN 0035-8711.
  5. ^ Ciprini, Stefano (December 2018). "Fermi LAT detection of a GeV gamma-ray flare from blazar OQ 334 (B2 1420+32)". The Astronomer's Telegram. 12277: 1. Bibcode:2018ATel12277....1C.
  6. ^ Malik, Zahoor; Akbar, Sikandar; Shah, Zahir; Misra, Ranjeev; Dar, Athar A; Manzoor, Aaqib; Ahanger, Sajad; Nazir, Zeeshan; Iqbal, Naseer; Rubab, Seemin; Tantry, Javaid (2025-04-15). "Statistical Insights into flux and photon index distributions of VHE FSRQs from Fermi-LAT observations". Monthly Notices of the Royal Astronomical Society. 539 (3): 2185–2201. doi:10.1093/mnras/staf620. ISSN 0035-8711.
  7. ^ "A New Large NIR Flare of the blazar HB891420+326". The Astronomer's Telegram. Retrieved 2025-07-14.
  8. ^ Carrasco, L.; Escobedo, G.; Porras, A.; Recillas, E.; Felix, L. (April 2023). "New Giant NIR flare of the FSRQ HB891420+326". The Astronomer's Telegram. 16021: 1. Bibcode:2023ATel16021....1C.
  9. ^ "Detection of very-high-energy gamma-ray emission from B2 1420+32 with the MAGIC telescopes". The Astronomer's Telegram. Retrieved 2025-07-14.
  10. ^ "A strong optical flaring from the Seyfert 1 Galaxy OQ 334 (B2 1420+326)". The Astronomer's Telegram. Retrieved 2025-07-14.
  11. ^ a b c Acciari, V. A.; Ansoldi, S.; Antonelli, L. A.; Engels, A. Arbet; Artero, M.; Asano, K.; Baack, D.; Babić, A.; Baquero, A.; Almeida, U. Barres de; Barrio, J. A.; González, J. Becerra; Bednarek, W.; Bellizzi, L.; Bernardini, E. (2021-03-01). "VHE gamma-ray detection of FSRQ QSO B1420+326 and modeling of its enhanced broadband state in 2020". Astronomy & Astrophysics. 647: A163. arXiv:2012.11380. Bibcode:2021A&A...647A.163M. doi:10.1051/0004-6361/202039687. ISSN 0004-6361.
  12. ^ "Continuing flux density increase in OQ 334 revealed by Sardinia Radio Telescope dual-frequency observations". The Astronomer's Telegram. Retrieved 2025-07-14.
  13. ^ "Radio Flaring of the Quasar B2 1420+32". The Astronomer's Telegram. Retrieved 2025-07-14.
  14. ^ Xiao, Hu-Bing; Cao, Hai-Tao; Xue, Rui; Cai, Jin-Ting; Wang, Ge-Ge; Manganaro, Marina; Zhang, Shao-Hua; Ouyang, Zhi-Hao; Fu, Li-Ping; Fan, Jun-Hui (2024-05-28). "Probing the Gamma-Ray Emission Region of Five TeV Flat Spectrum Radio Quasars". Research in Astronomy and Astrophysics. 24 (6): 065013. Bibcode:2024RAA....24f5013X. doi:10.1088/1674-4527/ad420e. ISSN 1674-4527.
  15. ^ "ASAS-SN Discovery of an Unprecedented >2 Magnitude Optical Flare from QSO B2 1420+32". The Astronomer's Telegram. Retrieved 2025-07-14.
  16. ^ a b "B2 1420+32 is in high optical and polarization state". The Astronomer's Telegram. Retrieved 2025-07-14.
  17. ^ a b "B2 1420+32 is brightening in optical". The Astronomer's Telegram. Retrieved 2025-07-14.
  18. ^ Brotherton, Michael S.; Singh, Vikram; Runnoe, Jessie (2015-12-21). "Orientation and quasar black hole mass estimation". Monthly Notices of the Royal Astronomical Society. 454 (4): 3864–3871. arXiv:1509.06468. doi:10.1093/mnras/stv2186. ISSN 0035-8711.
  19. ^ Mishra, Hora D.; Dai, Xinyu; Chen, Ping; Cheng, Jigui; Jayasinghe, T.; Tucker, Michael A.; Vallely, Patrick J.; Bersier, David; Bose, Subhash; Do, Aaron; Dong, Subo; Holoien, Thomas W.-S.; Huber, Mark E.; Kochanek, Christopher S.; Liang, Enwei (2021-06-01). "The Changing-look Blazar B2 1420+32". The Astrophysical Journal. 913 (2): 146. arXiv:2103.08707. Bibcode:2021ApJ...913..146M. doi:10.3847/1538-4357/abf63d. ISSN 0004-637X.
  20. ^ a b Nowakowski, Tomasz; Phys.org. "B2 1420+32 is a changing-look blazar, study finds". phys.org. Retrieved 2025-07-14.
  21. ^ a b Ren, S. S.; Zhou, R. X.; Zheng, Y. G.; Kang, S. J.; Wu, Q. (2024-05-01). "The Fermi-LAT view of the changing-look blazar OQ 334". Astronomy & Astrophysics. 685: A140. arXiv:2402.17099. Bibcode:2024A&A...685A.140R. doi:10.1051/0004-6361/202347312. ISSN 0004-6361.
  22. ^ Chand, Krishan; Gopal-Krishna (2025-05-15). "The alternating 'changing-look' blazar OQ 334 (B2 1420+32): new observational clues to the blazar state transitions". Monthly Notices of the Royal Astronomical Society: Letters. 541 (1): L52 – L57. doi:10.1093/mnrasl/slaf053. ISSN 1745-3925.
  23. ^ Ren, S. S.; Zhou, R. X.; Zheng, Y. G.; Kang, S. J. (2024-11-01). "The Oscillation in Evolution of Changing-look Blazar OQ 334". The Astrophysical Journal. 976 (1): 124. arXiv:2411.08313. Bibcode:2024ApJ...976..124R. doi:10.3847/1538-4357/ad83ce. ISSN 0004-637X.
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