Astronomy:IERS B1946+708

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IERS B1946+708
The radio galaxy IERS B1946+708.
Observation data (J2000.0 epoch)
ConstellationDraco
Right ascension 19h 45m 53.520s[1]
Declination+70° 55′ 48.727″[1]
Redshift0.100830[1]
Helio radial velocity30,228 km/s[1]
Distance1.256 Gly
Apparent magnitude (V)16.70
Apparent magnitude (B)18.72
Characteristics
TypeE Blazar[1]
Size~249,400 ly (76.48 kpc) (estimated)[1]
Other designations
S5 1946+70, WN B1946+7048, LEDA 2739486, 87GB 194612.4+704824, NVSS J194553+705548, 1946+708[1]

IERS B1946+708 is a radio galaxy located in the constellation of Draco. It has a redshift of (z) 0.101, identified by emission lines in its optical spectrum,[2] estimating it to be 1.25 billion light-years away.[1] and was first discovered as an extragalactic radio source by astronomers in 1983.[3] This object is classified as a compact symmetric object (CSO) in literature, but also has a gigahertz peaked spectrum.[4][5][6]

Description

IERS B1946+708 is described as an elliptical galaxy. It is known to have a disk described as inclined with a measurement of 600 parsecs in radius based on three-band imaging by Hubble Space Telescope. The nuclear regions of the galaxy are depicted to be much redder compared to its outer regions with B and R band magnitudes of 2-3. A companion galaxy can be seen 67 kiloparsecs away from it.[7]

The source of IERS B1946+708 is known to be compact. It is described as having an S-symmetry[8] with its radio core located halfway in the middle of two hotspots located in north and south directions.[9] The hotspots are estimated to have an expansion velocity of 0.024c which corresponds to the age of 4000 ± 1000 years[10] while the core has an inverted spectrum.[8] Two narrow jets are found emerging from the core, subsequently bending and ending in the hotspot regions.[8][11] These jets are known to contain four components which are found to move at speeds of between 0.6 and 0.9c with the fastest component having a velocity of 1.09 h-1 c.[11][12]

Low polarization have also been observed in the jet components of IERS B1946+708 indicating Faraday depolarization by ionized gas and a tangled magnetic field.[11] Neural hydrogen have also been detected in all of the components, with narrow lines evidently present towards the north hotspot likely caused by H I clouds associating with a warm region of gas.[13][14]

X-ray observations by BeppoSAX found IERS B1946+708 has a strong presence of iron K-alpha emission lines in its spectrum.[15][16] H I observations conducted by A.B. Peck and G.B. Taylor, found the source has multi-peaked absorption throughout its radio continuum with the maximum column density located towards the core, displaying velocity dispersion of 350 kilometers per seconds. This suggests IERS B1946+708 has a circumnuclear disk.[17][18]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 "Results for IERS B1946+708". https://ned.ipac.caltech.edu/byname?objname=LEDA+2739486&hconst=67.8&omegam=0.308&omegav=0.692&wmap=4&corr_z=1. 
  2. ↑ Stickel, M.; Kuehr, H. (August 1993). "Spectroscopic observations of radio source identifications from the 1 Jy, S4 and S5 surveys. III." (in en). Astronomy and Astrophysics Supplement Series 100: 395–411. ISSN 0365-0138. https://articles.adsabs.harvard.edu/pdf/1993A%26AS..100..395S. 
  3. ↑ Morabito, D. D.; Preston, R. A.; Slade, M. A.; Jauncey, D. L.; Nicolson, G. D. (August 1983). "Arcsecond positions for milliarcsecond VLBI nuclei of extragalactic radio sources. II. 207 sources." (in en). The Astronomical Journal 88: 1138–1145. doi:10.1086/113403. ISSN 0004-6256. Bibcode: 1983AJ.....88.1138M. https://articles.adsabs.harvard.edu/pdf/1983AJ.....88.1138M. 
  4. ↑ Taylor, G. B (2003-10-01). "Observed properties of jets in young radio galaxies". New Astronomy Reviews. The physics of relativistic jets in the CHANDRA and XMM era 47 (6): 585–588. doi:10.1016/S1387-6473(03)00099-X. ISSN 1387-6473. Bibcode: 2003NewAR..47..585T. https://www.sciencedirect.com/science/article/abs/pii/S138764730300099X#:~:text=Compact%20Symmetric%20Objects%20(CSOs)%20are%20a%20recently,to%20be%20quite%20young%20(age%20%E2%88%BC1000%20years).. 
  5. ↑ Britzen, S.; Vermeulen, R. C.; Taylor, G. B.; Campbell, R. M.; Pearson, T. J.; Readhead, A. C. S.; Xu, W.; Browne, I. W. A. et al. (2007-09-01). "A multi-epoch VLBI survey of the kinematics of CJF sources - I. Model-fit parameters and maps" (in en). Astronomy & Astrophysics 472 (3): 763–771. doi:10.1051/0004-6361:20052677. ISSN 0004-6361. Bibcode: 2007A&A...472..763B. https://www.aanda.org/articles/aa/pdf/2007/36/aa2677-05.pdf. 
  6. ↑ Fanti, C.; Pozzi, F.; Fanti, R.; Baum, S. A.; O'Dea, C. P.; Bremer, M.; Dallacasa, D.; Falcke, H. et al. (June 2000). "ISO observations of a sample of Compact Steep Spectrum and GHz Peaked Spectrum radio galaxies" (in en). Astronomy and Astrophysics 358: 499–513. ISSN 0004-6361. Bibcode: 2000A&A...358..499F. 
  7. ↑ Perlman, Eric S.; Stocke, John T.; Conway, John; Reynolds, Chris (August 2001). "Host Galaxies, Obscuration, and Nuclear Structure of Three Nearby Compact Symmetric Objects" (in en). The Astronomical Journal 122 (2): 536–548. doi:10.1086/321149. ISSN 0004-6256. Bibcode: 2001AJ....122..536P. 
  8. ↑ 8.0 8.1 8.2 Taylor, G. B.; Vermeulen, R. C. (1997-08-10). "Bidirectional Relativistic Jets of the Radio Galaxy 1946+708: Constraints on the Hubble Constant". The Astrophysical Journal 485 (1): L9–L12. doi:10.1086/310800. ISSN 0004-637X. Bibcode: 1997ApJ...485L...9T. https://iopscience.iop.org/article/10.1086/310800/fulltext/. 
  9. ↑ Peck, A. B.; Taylor, G. B.; Conway, J. E. (1999-08-10). "Obscuration of the Parsec-Scale Jets in the Compact Symmetric Object 1946+708". The Astrophysical Journal 521 (1): 103–111. doi:10.1086/307535. ISSN 0004-637X. Bibcode: 1999ApJ...521..103P. https://iopscience.iop.org/article/10.1086/307535/fulltext/. 
  10. ↑ Willett, Kyle W.; Stocke, John T.; Darling, Jeremy; Perlman, Eric S. (2010-04-05). "SPITZER MID-INFRARED SPECTROSCOPY OF COMPACT SYMMETRIC OBJECTS: WHAT POWERS RADIO-LOUD ACTIVE GALACTIC NUCLEI?". The Astrophysical Journal 713 (2): 1393–1412. doi:10.1088/0004-637x/713/2/1393. ISSN 0004-637X. Bibcode: 2010ApJ...713.1393W. https://doi.org/10.1088/0004-637x/713/2/1393. 
  11. ↑ 11.0 11.1 11.2 Taylor, G. B.; Charlot, P.; Vermeulen, R. C.; Pradel, N. (2009-05-28). "Monitoring the Bidirectional Relativistic Jets of the Radio Galaxy 1946+708". The Astrophysical Journal 698 (2): 1282–1291. doi:10.1088/0004-637x/698/2/1282. ISSN 0004-637X. Bibcode: 2009ApJ...698.1282T. https://doi.org/10.1088/0004-637x/698/2/1282. 
  12. ↑ Taylor, G B; Vermeulen, R C; Pearson, T J (1995-12-05). "Bidirectional motion observed in the compact symmetric object 1946+708.". Proceedings of the National Academy of Sciences 92 (25): 11381–11384. doi:10.1073/pnas.92.25.11381. ISSN 0027-8424. PMID 11607603. Bibcode: 1995PNAS...9211381T. 
  13. ↑ Peck, A. B.; Taylor, G. B.; Menten, K. M. (2000-09-22), Parsec-Scale Imaging of HI Absorption in 1946+708, arXiv:astro-ph/0009371 
  14. ↑ Peck, A.B.; Taylor, G.B. (May 2002). "Imaging HI absorption toward symmetric radio galaxies—evidence for a circumnuclear torus". New Astronomy Reviews 46 (2–7): 273–277. doi:10.1016/s1387-6473(01)00192-0. ISSN 1387-6473. Bibcode: 2002NewAR..46..273P. 
  15. ↑ Woltjer, L.; Risaliti, G.; Salvati, M. (2003). "Beppo SAX X-Ray Observations of PKS 1934-63 and S5 1946+708". Publications of the Astronomical Society of Australia 20 (1): 155–156. doi:10.1071/ASv20n1_ABS. Bibcode: 2003PASA...20..156W. https://ui.adsabs.harvard.edu/abs/2003PASA...20..156W/abstract. 
  16. ↑ Risaliti, G.; Woltjer, L.; Salvati, M. (2003-04-01). "The nature of the absorbing torus in compact radio galaxies" (in en). Astronomy & Astrophysics 401 (3): 895–901. doi:10.1051/0004-6361:20030124. ISSN 0004-6361. Bibcode: 2003A&A...401..895R. https://www.aanda.org/articles/aa/pdf/2003/15/aah4021.pdf. 
  17. ↑ Peck, A. B.; Taylor, G. B. (2001-06-20). "Evidence for a Circumnuclear Disk in 1946+708". The Astrophysical Journal 554 (2): L147–L150. doi:10.1086/321699. ISSN 0004-637X. Bibcode: 2001ApJ...554L.147P. https://iopscience.iop.org/article/10.1086/321699/fulltext/. 
  18. ↑ Araya, E. D.; Rodríguez, C.; Pihlström, Y.; Taylor, G. B.; Tremblay, S.; Vermeulen, R. C. (2009-11-18). "Vlba Observations of H I in the Archetype Compact Symmetric Object B2352+495". The Astronomical Journal 139 (1): 17–26. doi:10.1088/0004-6256/139/1/17. ISSN 0004-6256. https://doi.org/10.1088/0004-6256/139/1/17. 




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